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• Why is syslog so much slower than file IO?

  - by ceving

  I wrote a simple test program to measure the performance of the syslog function. This are the results of my test system: (Debian 6.0.2 with Linux 2.6.32-5-amd64) Test Case Calls Payload Duration Thoughput [] [MB] [s] [MB/s] -------------------- ---------- ---------- ---------- ---------- syslog 200000 10.00 7.81 1.28 syslog %s 200000 10.00 9.94 1.01 write /dev/null 200000 10.00 0.03 343.93 printf %s 200000 10.00 0.13 76.29 The test program did 200000 system calls writing 50 Bytes of data during each call. Why is Syslog more than ten times slower than file IO? This is the program I used to perform the test: #include <fcntl.h> #include <stdio.h> #include <string.h> #include <sys/stat.h> #include <sys/time.h> #include <sys/types.h> #include <syslog.h> #include <unistd.h> const int iter = 200000; const char msg[] = "123456789 123456789 123456789 123456789 123456789"; struct timeval t0; struct timeval t1; void start () { gettimeofday (&t0, (void*)0); } void stop () { gettimeofday (&t1, (void*)0); } void report (char *action) { double dt = (double)t1.tv_sec - (double)t0.tv_sec + 1e-6 * ((double)t1.tv_usec - (double)t0.tv_usec); double mb = 1e-6 * sizeof (msg) * iter; if (action == NULL) printf ("Test Case Calls Payload Duration Thoughput \n" " [] [MB] [s] [MB/s] \n" "-------------------- ---------- ---------- ---------- ----------\n"); else { if (strlen (action) > 20) action[20] = 0; printf ("%-20s %-10d %-10.2f %-10.2f %-10.2f\n", action, iter, mb, dt, mb / dt); } } void test_syslog () { int i; openlog ("test_syslog", LOG_PID | LOG_NDELAY, LOG_LOCAL0); start (); for (i = 0; i < iter; i++) syslog (LOG_DEBUG, msg); stop (); closelog (); report ("syslog"); } void test_syslog_format () { int i; openlog ("test_syslog", LOG_PID | LOG_NDELAY, LOG_LOCAL0); start (); for (i = 0; i < iter; i++) syslog (LOG_DEBUG, "%s", msg); stop (); closelog (); report ("syslog %s"); } void test_write_devnull () { int i, fd; fd = open ("/dev/null", O_WRONLY); start (); for (i = 0; i < iter; i++) write (fd, msg, sizeof(msg)); stop (); close (fd); report ("write /dev/null"); } void test_printf () { int i; FILE *fp; fp = fopen ("/tmp/test_printf", "w"); start (); for (i = 0; i < iter; i++) fprintf (fp, "%s", msg); stop (); fclose (fp); report ("printf %s"); } int main (int argc, char **argv) { report (NULL); test_syslog (); test_syslog_format (); test_write_devnull (); test_printf (); }

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• ls -l freezes terminal locally and remotely

  - by Jakobud

  I've been reading other SF threads regarding ls not returning results or freezing and stalling terminal sessions and it appears they usually the fault of network problems. My problem however, occurs both over remote SSH sessions but also if I am physically at the server itself... I just installed CentOS 5.4 on one of our servers. I'm setting up some rdiff-backup scripts and when I downloaded librsync and untared it, thats when I started seeing some weird behavior with ls -l. wget http://sourceforge.net/projects/librsync/files/librsync/0.9.7/librsync-0.9.7.tar.gz/download /tmp cd /tmp tar -xzf librsync-0.9.7.tar.gz Simple enough. To view the files in this directory I did this: ls results: librsync-0.9.7 librsync-0.9.7.tar.gz Now, if I ls -l, my terminal freezes. I have to re-ssh in to keep going. After reading SF threads, I thought it was network related. So I was extremely surprised to go sit down at the server itself and see the exact same thing happen... So its obviously not a network issues. Even if I ls /tmp/librsync-0.9.7, my terminal freezes just the same... Next I did an strace and got this (warning: wall of text coming....): strace ls -l /tmp execve("/bin/ls", ["ls", "-l", "/tmp"], [/* 21 vars */]) = 0 brk(0) = 0x1c521000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2b8582cc0000 uname({sys="Linux", node="massive.answeron.com", ...}) = 0 access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory) open("/etc/ld.so.cache", O_RDONLY) = 3 fstat(3, {st_mode=S_IFREG|0644, st_size=71746, ...}) = 0 mmap(NULL, 71746, PROT_READ, MAP_PRIVATE, 3, 0) = 0x2b8582cc1000 close(3) = 0 open("/lib64/librt.so.1", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0 \"\200\2730\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0755, st_size=53448, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2b8582cd3000 mmap(0x30bb800000, 2132936, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x30bb800000 mprotect(0x30bb807000, 2097152, PROT_NONE) = 0 mmap(0x30bba07000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x7000) = 0x30bba07000 close(3) = 0 open("/lib64/libacl.so.1", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\0\31@\2740\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0755, st_size=28008, ...}) = 0 mmap(0x30bc400000, 2120992, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x30bc400000 mprotect(0x30bc406000, 2093056, PROT_NONE) = 0 mmap(0x30bc605000, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x5000) = 0x30bc605000 close(3) = 0 open("/lib64/libselinux.so.1", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0`E\300\2730\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0755, st_size=95464, ...}) = 0 mmap(0x30bbc00000, 2192784, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x30bbc00000 mprotect(0x30bbc15000, 2097152, PROT_NONE) = 0 mmap(0x30bbe15000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x15000) = 0x30bbe15000 mmap(0x30bbe17000, 1424, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x30bbe17000 close(3) = 0 open("/lib64/libc.so.6", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\220\332\201\2720\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0755, st_size=1717800, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2b8582cd4000 mmap(0x30ba800000, 3498328, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x30ba800000 mprotect(0x30ba94d000, 2097152, PROT_NONE) = 0 mmap(0x30bab4d000, 20480, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x14d000) = 0x30bab4d000 mmap(0x30bab52000, 16728, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x30bab52000 close(3) = 0 open("/lib64/libpthread.so.0", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\220W\0\2730\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0755, st_size=145824, ...}) = 0 mmap(0x30bb000000, 2204528, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x30bb000000 mprotect(0x30bb016000, 2093056, PROT_NONE) = 0 mmap(0x30bb215000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x15000) = 0x30bb215000 mmap(0x30bb217000, 13168, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x30bb217000 close(3) = 0 open("/lib64/libattr.so.1", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\320\17\300\2750\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0755, st_size=17888, ...}) = 0 mmap(0x30bdc00000, 2110728, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x30bdc00000 mprotect(0x30bdc04000, 2093056, PROT_NONE) = 0 mmap(0x30bde03000, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x3000) = 0x30bde03000 close(3) = 0 open("/lib64/libdl.so.2", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\20\16\300\2720\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0755, st_size=23360, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2b8582cd5000 mmap(0x30bac00000, 2109696, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x30bac00000 mprotect(0x30bac02000, 2097152, PROT_NONE) = 0 mmap(0x30bae02000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x2000) = 0x30bae02000 close(3) = 0 open("/lib64/libsepol.so.1", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\0=\0\2740\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0755, st_size=247496, ...}) = 0 mmap(0x30bc000000, 2383136, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x30bc000000 mprotect(0x30bc03b000, 2097152, PROT_NONE) = 0 mmap(0x30bc23b000, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x3b000) = 0x30bc23b000 mmap(0x30bc23c000, 40224, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x30bc23c000 close(3) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2b8582cd6000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2b8582cd7000 arch_prctl(ARCH_SET_FS, 0x2b8582cd6c50) = 0 mprotect(0x30bba07000, 4096, PROT_READ) = 0 mprotect(0x30bab4d000, 16384, PROT_READ) = 0 mprotect(0x30bb215000, 4096, PROT_READ) = 0 mprotect(0x30ba61b000, 4096, PROT_READ) = 0 mprotect(0x30bae02000, 4096, PROT_READ) = 0 munmap(0x2b8582cc1000, 71746) = 0 set_tid_address(0x2b8582cd6ce0) = 24102 set_robust_list(0x2b8582cd6cf0, 0x18) = 0 futex(0x7fff72d02d6c, FUTEX_WAKE_PRIVATE, 1) = 0 rt_sigaction(SIGRTMIN, {0x30bb005370, [], SA_RESTORER|SA_SIGINFO, 0x30bb00e7c0}, NULL, 8) = 0 rt_sigaction(SIGRT_1, {0x30bb0052b0, [], SA_RESTORER|SA_RESTART|SA_SIGINFO, 0x30bb00e7c0}, NULL, 8) = 0 rt_sigprocmask(SIG_UNBLOCK, [RTMIN RT_1], NULL, 8) = 0 getrlimit(RLIMIT_STACK, {rlim_cur=10240*1024, rlim_max=RLIM_INFINITY}) = 0 access("/etc/selinux/", F_OK) = 0 brk(0) = 0x1c521000 brk(0x1c542000) = 0x1c542000 open("/etc/selinux/config", O_RDONLY) = 3 fstat(3, {st_mode=S_IFREG|0644, st_size=448, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2b8582cc1000 read(3, "# This file controls the state o"..., 4096) = 448 read(3, "", 4096) = 0 close(3) = 0 munmap(0x2b8582cc1000, 4096) = 0 open("/proc/mounts", O_RDONLY) = 3 fstat(3, {st_mode=S_IFREG|0444, st_size=0, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2b8582cc1000 read(3, "rootfs / rootfs rw 0 0\n/dev/root"..., 4096) = 577 close(3) = 0 munmap(0x2b8582cc1000, 4096) = 0 open("/selinux/mls", O_RDONLY) = 3 read(3, "1", 19) = 1 close(3) = 0 socket(PF_FILE, SOCK_STREAM, 0) = 3 connect(3, {sa_family=AF_FILE, path="/var/run/setrans/.setrans-unix"...}, 110) = 0 sendmsg(3, {msg_name(0)=NULL, msg_iov(5)=[{"\1\0\0\0", 4}, {"\1\0\0\0", 4}, {"\1\0\0\0", 4}, {"\0", 1}, {"\0", 1}], msg_controllen=0, msg_flags=0}, MSG_NOSIGNAL) = 14 readv(3, [{"\1\0\0\0", 4}, {"\1\0\0\0", 4}, {"\0\0\0\0", 4}], 3) = 12 readv(3, [{"\0", 1}], 1) = 1 close(3) = 0 open("/usr/lib/locale/locale-archive", O_RDONLY) = 3 fstat(3, {st_mode=S_IFREG|0644, st_size=56413824, ...}) = 0 mmap(NULL, 56413824, PROT_READ, MAP_PRIVATE, 3, 0) = 0x2b8582cd8000 close(3) = 0 ioctl(1, SNDCTL_TMR_TIMEBASE or TCGETS, {B38400 opost isig icanon echo ...}) = 0 ioctl(1, TIOCGWINSZ, {ws_row=65, ws_col=137, ws_xpixel=0, ws_ypixel=0}) = 0 open("/usr/share/locale/locale.alias", O_RDONLY) = 3 fstat(3, {st_mode=S_IFREG|0644, st_size=2528, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2b85862a5000 read(3, "# Locale name alias data base.\n#"..., 4096) = 2528 read(3, "", 4096) = 0 close(3) = 0 munmap(0x2b85862a5000, 4096) = 0 open("/usr/share/locale/en_US.UTF-8/LC_TIME/coreutils.mo", O_RDONLY) = -1 ENOENT (No such file or directory) open("/usr/share/locale/en_US.utf8/LC_TIME/coreutils.mo", O_RDONLY) = -1 ENOENT (No such file or directory) open("/usr/share/locale/en_US/LC_TIME/coreutils.mo", O_RDONLY) = -1 ENOENT (No such file or directory) open("/usr/share/locale/en.UTF-8/LC_TIME/coreutils.mo", O_RDONLY) = -1 ENOENT (No such file or directory) open("/usr/share/locale/en.utf8/LC_TIME/coreutils.mo", O_RDONLY) = -1 ENOENT (No such file or directory) open("/usr/share/locale/en/LC_TIME/coreutils.mo", O_RDONLY) = -1 ENOENT (No such file or directory) lstat("/tmp", {st_mode=S_IFDIR|S_ISVTX|0777, st_size=4096, ...}) = 0 getxattr("/tmp", "system.posix_acl_access", 0x0, 0) = -1 ENODATA (No data available) getxattr("/tmp", "system.posix_acl_default", 0x0, 0) = -1 ENODATA (No data available) socket(PF_FILE, SOCK_STREAM, 0) = 3 fcntl(3, F_SETFL, O_RDWR|O_NONBLOCK) = 0 connect(3, {sa_family=AF_FILE, path="/var/run/nscd/socket"...}, 110) = -1 ENOENT (No such file or directory) close(3) = 0 socket(PF_FILE, SOCK_STREAM, 0) = 3 fcntl(3, F_SETFL, O_RDWR|O_NONBLOCK) = 0 connect(3, {sa_family=AF_FILE, path="/var/run/nscd/socket"...}, 110) = -1 ENOENT (No such file or directory) close(3) = 0 open("/etc/nsswitch.conf", O_RDONLY) = 3 fstat(3, {st_mode=S_IFREG|0644, st_size=1711, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2b85862a5000 read(3, "#\n# /etc/nsswitch.conf\n#\n# An ex"..., 4096) = 1711 read(3, "", 4096) = 0 close(3) = 0 munmap(0x2b85862a5000, 4096) = 0 open("/etc/ld.so.cache", O_RDONLY) = 3 fstat(3, {st_mode=S_IFREG|0644, st_size=71746, ...}) = 0 mmap(NULL, 71746, PROT_READ, MAP_PRIVATE, 3, 0) = 0x2b85862a5000 close(3) = 0 open("/lib64/libnss_files.so.2", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\340\37\0\0\0\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0755, st_size=53880, ...}) = 0 mmap(NULL, 2139432, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x2b85862b7000 mprotect(0x2b85862c1000, 2093056, PROT_NONE) = 0 mmap(0x2b85864c0000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x9000) = 0x2b85864c0000 close(3) = 0 mprotect(0x2b85864c0000, 4096, PROT_READ) = 0 munmap(0x2b85862a5000, 71746) = 0 open("/etc/passwd", O_RDONLY) = 3 fcntl(3, F_GETFD) = 0 fcntl(3, F_SETFD, FD_CLOEXEC) = 0 fstat(3, {st_mode=S_IFREG|0644, st_size=1823, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2b85862a5000 read(3, "root:x:0:0:root:/root:/bin/bash\n"..., 4096) = 1823 close(3) = 0 munmap(0x2b85862a5000, 4096) = 0 socket(PF_FILE, SOCK_STREAM, 0) = 3 fcntl(3, F_SETFL, O_RDWR|O_NONBLOCK) = 0 connect(3, {sa_family=AF_FILE, path="/var/run/nscd/socket"...}, 110) = -1 ENOENT (No such file or directory) close(3) = 0 socket(PF_FILE, SOCK_STREAM, 0) = 3 fcntl(3, F_SETFL, O_RDWR|O_NONBLOCK) = 0 connect(3, {sa_family=AF_FILE, path="/var/run/nscd/socket"...}, 110) = -1 ENOENT (No such file or directory) close(3) = 0 open("/etc/group", O_RDONLY) = 3 fcntl(3, F_GETFD) = 0 fcntl(3, F_SETFD, FD_CLOEXEC) = 0 fstat(3, {st_mode=S_IFREG|0644, st_size=743, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2b85862a5000 read(3, "root:x:0:root\nbin:x:1:root,bin,d"..., 4096) = 743 close(3) = 0 munmap(0x2b85862a5000, 4096) = 0 open("/tmp", O_RDONLY|O_NONBLOCK|O_DIRECTORY) = 3 fcntl(3, F_SETFD, FD_CLOEXEC) = 0 getdents(3, /* 8 entries */, 32768) = 264 lstat("/tmp/librsync-0.9.7.tar.gz", {st_mode=S_IFREG|0644, st_size=453802, ...}) = 0 getxattr("/tmp/librsync-0.9.7.tar.gz", "system.posix_acl_access", 0x0, 0) = -1 ENODATA (No data available) getxattr("/tmp/librsync-0.9.7.tar.gz", "system.posix_acl_default", 0x0, 0) = -1 ENODATA (No data available) lstat("/tmp/librsync-0.9.7", {st_mode=S_IFDIR|0777, st_size=4096, ...}) = 0 getxattr("/tmp/librsync-0.9.7", "system.posix_acl_access", 0x0, 0) = -1 ENODATA (No data available) getxattr("/tmp/librsync-0.9.7", "system.posix_acl_default", 0x0, 0) = -1 ENODATA (No data available) open("/etc/passwd", O_RDONLY) = 4 fcntl(4, F_GETFD) = 0 fcntl(4, F_SETFD, FD_CLOEXEC) = 0 fstat(4, {st_mode=S_IFREG|0644, st_size=1823, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2b85862a5000 read(4, "root:x:0:0:root:/root:/bin/bash\n"..., 4096) = 1823 read(4, "", 4096) = 0 close(4) = 0 munmap(0x2b85862a5000, 4096) = 0 open("/etc/ld.so.cache", O_RDONLY) = 4 fstat(4, {st_mode=S_IFREG|0644, st_size=71746, ...}) = 0 mmap(NULL, 71746, PROT_READ, MAP_PRIVATE, 4, 0) = 0x2b85862a5000 close(4) = 0 open("/lib64/libnss_ldap.so.2", O_RDONLY) = 4 read(4, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\300r\4\0\0\0\0\0"..., 832) = 832 fstat(4, {st_mode=S_IFREG|0755, st_size=3169960, ...}) = 0 mmap(NULL, 5329912, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 4, 0) = 0x2b85864c2000 mprotect(0x2b858679e000, 2093056, PROT_NONE) = 0 mmap(0x2b858699d000, 176128, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 4, 0x2db000) = 0x2b858699d000 mmap(0x2b85869c8000, 62456, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x2b85869c8000 close(4) = 0 open("/lib64/libcom_err.so.2", O_RDONLY) = 4 read(4, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\320\n\300\2770\0\0\0"..., 832) = 832 fstat(4, {st_mode=S_IFREG|0755, st_size=10000, ...}) = 0 mmap(0x30bfc00000, 2103048, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 4, 0) = 0x30bfc00000 mprotect(0x30bfc02000, 2093056, PROT_NONE) = 0 mmap(0x30bfe01000, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 4, 0x1000) = 0x30bfe01000 close(4) = 0 open("/lib64/libkeyutils.so.1", O_RDONLY) = 4 read(4, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0`\n@\2760\0\0\0"..., 832) = 832 fstat(4, {st_mode=S_IFREG|0755, st_size=9472, ...}) = 0 mmap(0x30be400000, 2102416, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 4, 0) = 0x30be400000 mprotect(0x30be402000, 2093056, PROT_NONE) = 0 mmap(0x30be601000, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 4, 0x1000) = 0x30be601000 close(4) = 0 open("/lib64/libresolv.so.2", O_RDONLY) = 4 read(4, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\2402\0\2760\0\0\0"..., 832) = 832 fstat(4, {st_mode=S_IFREG|0755, st_size=92736, ...}) = 0 mmap(0x30be000000, 2181864, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 4, 0) = 0x30be000000 mprotect(0x30be011000, 2097152, PROT_NONE) = 0 mmap(0x30be211000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 4, 0x11000) = 0x30be211000 mmap(0x30be213000, 6888, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x30be213000 close(4) = 0 mprotect(0x30be211000, 4096, PROT_READ) = 0 munmap(0x2b85862a5000, 71746) = 0 rt_sigaction(SIGPIPE, {0x1, [], SA_RESTORER, 0x30ba8302d0}, {SIG_DFL, [], 0}, 8) = 0 geteuid() = 0 futex(0x2b85869c7708, FUTEX_WAKE_PRIVATE, 2147483647) = 0 open("/etc/ldap.conf", O_RDONLY) = 4 fstat(4, {st_mode=S_IFREG|0644, st_size=9119, ...}) = 0 fstat(4, {st_mode=S_IFREG|0644, st_size=9119, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2b85862a5000 read(4, "# @(#)$Id: ldap.conf,v 1.38 2006"..., 4096) = 4096 read(4, "Use the OpenLDAP password change"..., 4096) = 4096 read(4, " OpenLDAP 2.0 and earlier is \"no"..., 4096) = 927 read(4, "", 4096) = 0 close(4) = 0 munmap(0x2b85862a5000, 4096) = 0 uname({sys="Linux", node="massive.answeron.com", ...}) = 0 open("/etc/resolv.conf", O_RDONLY) = 4 fstat(4, {st_mode=S_IFREG|0644, st_size=107, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2b85862a5000 read(4, "; generated by /sbin/dhclient-sc"..., 4096) = 107 read(4, "", 4096) = 0 close(4) = 0 munmap(0x2b85862a5000, 4096) = 0 socket(PF_FILE, SOCK_STREAM, 0) = 4 fcntl(4, F_SETFL, O_RDWR|O_NONBLOCK) = 0 connect(4, {sa_family=AF_FILE, path="/var/run/nscd/socket"...}, 110) = -1 ENOENT (No such file or directory) close(4) = 0 socket(PF_FILE, SOCK_STREAM, 0) = 4 fcntl(4, F_SETFL, O_RDWR|O_NONBLOCK) = 0 connect(4, {sa_family=AF_FILE, path="/var/run/nscd/socket"...}, 110) = -1 ENOENT (No such file or directory) close(4) = 0 open("/etc/host.conf", O_RDONLY) = 4 fstat(4, {st_mode=S_IFREG|0644, st_size=17, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2b85862a5000 read(4, "order hosts,bind\n", 4096) = 17 read(4, "", 4096) = 0 close(4) = 0 munmap(0x2b85862a5000, 4096) = 0 futex(0x30bab54d44, FUTEX_WAKE_PRIVATE, 2147483647) = 0 open("/etc/hosts", O_RDONLY) = 4 fcntl(4, F_GETFD) = 0 fcntl(4, F_SETFD, FD_CLOEXEC) = 0 fstat(4, {st_mode=S_IFREG|0644, st_size=187, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2b85862a5000 read(4, "# Do not remove the following li"..., 4096) = 187 read(4, "", 4096) = 0 close(4) = 0 munmap(0x2b85862a5000, 4096) = 0 open("/etc/ld.so.cache", O_RDONLY) = 4 fstat(4, {st_mode=S_IFREG|0644, st_size=71746, ...}) = 0 mmap(NULL, 71746, PROT_READ, MAP_PRIVATE, 4, 0) = 0x2b85862a5000 close(4) = 0 open("/lib64/libnss_dns.so.2", O_RDONLY) = 4 read(4, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\340\17\0\0\0\0\0\0"..., 832) = 832 fstat(4, {st_mode=S_IFREG|0755, st_size=23736, ...}) = 0 mmap(NULL, 2113792, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 4, 0) = 0x2b85869d8000 mprotect(0x2b85869dc000, 2093056, PROT_NONE) = 0 mmap(0x2b8586bdb000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 4, 0x3000) = 0x2b8586bdb000 close(4) = 0 mprotect(0x2b8586bdb000, 4096, PROT_READ) = 0 munmap(0x2b85862a5000, 71746) = 0 socket(PF_INET, SOCK_DGRAM, IPPROTO_IP) = 4 connect(4, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("192.168.10.20")}, 28) = 0 fcntl(4, F_GETFL) = 0x2 (flags O_RDWR) fcntl(4, F_SETFL, O_RDWR|O_NONBLOCK) = 0 gettimeofday({1276265920, 823870}, NULL) = 0 poll([{fd=4, events=POLLOUT}], 1, 0) = 1 ([{fd=4, revents=POLLOUT}]) sendto(4, "C\v\1\0\0\1\0\0\0\0\0\0\7massive\10answeron\3co"..., 38, MSG_NOSIGNAL, NULL, 0) = 38 poll([{fd=4, events=POLLIN}], 1, 5000) = 1 ([{fd=4, revents=POLLIN}]) ioctl(4, FIONREAD, [122]) = 0 recvfrom(4, "C\v\205\200\0\1\0\1\0\2\0\2\7massive\10answeron\3co"..., 1024, 0, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("192.168.10.20")}, [16]) = 122 close(4) = 0 open("/etc/openldap/ldap.conf", O_RDONLY) = 4 fstat(4, {st_mode=S_IFREG|0644, st_size=335, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2b85862a5000 read(4, "#\n# LDAP Defaults\n#\n\n# See ldap."..., 4096) = 335 read(4, "", 4096) = 0 close(4) = 0 munmap(0x2b85862a5000, 4096) = 0 getuid() = 0 geteuid() = 0 getgid() = 0 getegid() = 0 open("/root/ldaprc", O_RDONLY) = -1 ENOENT (No such file or directory) open("/root/.ldaprc", O_RDONLY) = -1 ENOENT (No such file or directory) stat("/etc/ldap.conf", {st_mode=S_IFREG|0644, st_size=9119, ...}) = 0 geteuid() = 0 brk(0x1c566000) = 0x1c566000 open("/etc/hosts", O_RDONLY) = 4 fcntl(4, F_GETFD) = 0 fcntl(4, F_SETFD, FD_CLOEXEC) = 0 fstat(4, {st_mode=S_IFREG|0644, st_size=187, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2b85862a5000 read(4, "# Do not remove the following li"..., 4096) = 187 read(4, "", 4096) = 0 close(4) = 0 munmap(0x2b85862a5000, 4096) = 0 open("/etc/hosts", O_RDONLY) = 4 fcntl(4, F_GETFD) = 0 fcntl(4, F_SETFD, FD_CLOEXEC) = 0 fstat(4, {st_mode=S_IFREG|0644, st_size=187, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2b85862a5000 read(4, "# Do not remove the following li"..., 4096) = 187 read(4, "", 4096) = 0 close(4) = 0 munmap(0x2b85862a5000, 4096) = 0 socket(PF_INET, SOCK_DGRAM, IPPROTO_IP) = 4 connect(4, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("192.168.10.20")}, 28) = 0 fcntl(4, F_GETFL) = 0x2 (flags O_RDWR) fcntl(4, F_SETFL, O_RDWR|O_NONBLOCK) = 0 gettimeofday({1276265920, 855948}, NULL) = 0 poll([{fd=4, events=POLLOUT}], 1, 0) = 1 ([{fd=4, revents=POLLOUT}]) sendto(4, "\32 \1\0\0\1\0\0\0\0\0\0\4ldap\10answeron\3com\0\0"..., 35, MSG_NOSIGNAL, NULL, 0) = 35 poll([{fd=4, events=POLLIN}], 1, 5000) = 1 ([{fd=4, revents=POLLIN}]) ioctl(4, FIONREAD, [104]) = 0 recvfrom(4, "\32 \205\200\0\1\0\1\0\1\0\0\4ldap\10answeron\3com\0\0"..., 1024, 0, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("192.168.10.20")}, [16]) = 104 close(4) = 0 socket(PF_INET, SOCK_DGRAM, IPPROTO_IP) = 4 connect(4, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("192.168.10.20")}, 28) = 0 fcntl(4, F_GETFL) = 0x2 (flags O_RDWR) fcntl(4, F_SETFL, O_RDWR|O_NONBLOCK) = 0 gettimeofday({1276265920, 858536}, NULL) = 0 poll([{fd=4, events=POLLOUT}], 1, 0) = 1 ([{fd=4, revents=POLLOUT}]) sendto(4, "I\375\1\0\0\1\0\0\0\0\0\0\4ldap\10answeron\3com\0\0"..., 35, MSG_NOSIGNAL, NULL, 0) = 35 poll([{fd=4, events=POLLIN}], 1, 5000) = 1 ([{fd=4, revents=POLLIN}]) ioctl(4, FIONREAD, [139]) = 0 recvfrom(4, "I\375\205\200\0\1\0\2\0\2\0\2\4ldap\10answeron\3com\0\0"..., 1024, 0, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("192.168.10.20")}, [16]) = 139 close(4) = 0 socket(PF_INET, SOCK_STREAM, IPPROTO_IP) = 4 fcntl(4, F_SETFD, FD_CLOEXEC) = 0 setsockopt(4, SOL_SOCKET, SO_KEEPALIVE, [1], 4) = 0 setsockopt(4, SOL_TCP, TCP_NODELAY, [1], 4) = 0 fcntl(4, F_GETFL) = 0x2 (flags O_RDWR) fcntl(4, F_SETFL, O_RDWR|O_NONBLOCK) = 0 connect(4, {sa_family=AF_INET, sin_port=htons(389), sin_addr=inet_addr("10.20.0.30")}, 16) = -1 EINPROGRESS (Operation now in progress) poll([{fd=4, events=POLLOUT|POLLERR|POLLHUP}], 1, 120000 And thats where it stops, right there after that last 120000.... Using strace, I can obviously CTRL+C to keep going. But like I said, normally the terminal completely freezes. Anyone have any clues?

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• SVN do unnecessary chmod on .svn/tempfiles

  - by ???

  My working dir is on an TrueCrypt NTFS volume, with umask 000. So I can read/write on any files with no problem. But I can't do svn command on it, for example `svn update' shows error: svn: Can't set permissions on '.svn/tempfile.8.tmp': strace svn up gives: ... chmod("sbin/.svn/tempfile.2.tmp", 0770) = -1 EPERM (Operation not permitted) fcntl64(3, F_GETFL) = 0x2 (flags O_RDWR) fcntl64(3, F_SETFL, O_RDWR|O_NONBLOCK) = 0 write(3, "( failure ( ( 1 76:Can't set per"..., 172) = 172 fcntl64(3, F_GETFL) = 0x802 (flags O_RDWR|O_NONBLOCK) fcntl64(3, F_SETFL, O_RDWR) = 0 read(3, "( abort-edit ( ) ) ( failure ( ("..., 4096) = 191 gettimeofday({1276661368, 382789}, NULL) = 0 lstat64("sbin", {st_mode=S_IFDIR|0770, st_size=0, ...}) = 0 select(0, NULL, NULL, NULL, {0, 1000}) = 0 (Timeout) write(2, "svn: Can't set permissions on 's"..., 82svn: Can't set permissions on 'sbin/.svn/tempfile.2.tmp': Operation not permitted) = 82 close(3) = 0 So, the error occurred when svn chmod on some tmp files. But this is disallowed in the TrueCrypt volumes, and it's just unnecessary. Can I bypass the chmod lib calls when launch svn on TrueCrypt volumes?

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• localtime_r supposed to be thread safe, but causing errors in Valgrind DRD

  - by Nik

  I searched google as much as I could but I couldn't find any good answers to this. localtime_r is supposed to be a thread-safe function for getting the system time. However, when checking my application with Valgrind --tool=drd, it consistantly tells me that there is a data race condition on this function. Are the common search results lying to me, or am I just missing something? It doesn't seem efficient to surround each localtime_r call with a mutex, especially if it is supposed to by thread safe in the first place. here is how i'm using it: timeval handlerTime; gettimeofday(&handlerTime,NULL); tm handlerTm; localtime_r(&handlerTime.tv_sec,&handlerTm); Any ideas?

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• What time function do I need to use with pthread_cond_timedwait?

  - by Vincent

  The pthread_cond_timedwait function needs an absolute time in a time timespec structure. What time function I'm suppose to use to obtain the absolute time. I saw a lot of example on the web and I found almost all time function used. (ftime, clock, gettimeofday, clock_gettime (with all possible CLOCK_...). The pthread_cond_timedwait uses an absolute time. Will this waiting time affected by changing the time of the machine? Also if I get the absolute time with one of the time function, if the time of the machine change between the get and the addition of the delta time this will affect the affect the wait time? Is there a possibility to wait for an event with a relative time instead?

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• Apache HTTPD - Segmentation fault when loading mod_jk module

  - by hansengel

  I just set up mod_jk with my Apache httpd 2.0.52 installation, but now when I try to start Apache, it has a segmentation fault. I've checked that I am using the mod_jk compiled for 2.0.x.. built against the same version I have, in fact. I've also verified that the path I'm giving to LoadModule is correct, and the permissions and the ownership of the file are the same as the rest of the modules'. When I remove the "LoadModule" command for mod_jk from my httpd.conf, there is no segmentation fault. Nothing shows in Apache's error logs. I have tried restarting the server with this module using both service httpd restart and httpd. These are the last few lines returned of strace httpd -X: gettimeofday({1292100295, 434487}, NULL) = 0 socket(PF_INET6, SOCK_STREAM, IPPROTO_IP) = -1 EAFNOSUPPORT (Address family not supported by protocol) socket(PF_NETLINK, SOCK_RAW, 0) = 3 bind(3, {sa_family=AF_NETLINK, pid=0, groups=00000000}, 12) = 0 getsockname(3, {sa_family=AF_NETLINK, pid=22378, groups=00000000}, [12]) = 0 time(NULL) = 1292100295 sendto(3, "\24\0\0\0\26\0\1\3\307\342\3M\0\0\0\0\0\305\333\267", 20, 0, {sa_family=AF_NETLINK, pid=0, groups=00000000}, 12) = 20 recvmsg(3, {msg_name(12)={sa_family=AF_NETLINK, pid=0, groups=00000000}, msg_iov(1)=[{"<\0\0\0\24\0\2\0\307\342\3MjW\0\0\2\10\200\376\1\0\0\0"..., 4096}], msg_controllen=0, msg_flags=0}, 0) = 664 recvmsg(3, {msg_name(12)={sa_family=AF_NETLINK, pid=0, groups=00000000}, msg_iov(1)=[{"\24\0\0\0\3\0\2\0\307\342\3MjW\0\0\0\0\0\0\1\0\0\0\10\0"..., 4096}], msg_controllen=0, msg_flags=0}, 0) = 20 close(3) = 0 socket(PF_INET, SOCK_STREAM, IPPROTO_IP) = 3 --- SIGSEGV (Segmentation fault) @ 0 (0) --- +++ killed by SIGSEGV +++ Process 22378 detached Has anyone had a similar problem using Apache 2.0.52 with mod_jk? I might try downloading and building the source for the Apache server and mod_jk myself if there isn't a discovered fix for this.

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• Apache HTTPD - Segmentation fault when loading mod_jk module

  - by Hans Engel

  I just set up mod_jk with my Apache httpd 2.0.52 installation, but now when I try to start Apache, it has a segmentation fault. I've checked that I am using the mod_jk compiled for 2.0.x.. built against the same version I have, in fact. I've also verified that the path I'm giving to LoadModule is correct, and the permissions and the ownership of the file are the same as the rest of the modules'. When I remove the "LoadModule" command for mod_jk from my httpd.conf, there is no segmentation fault. Nothing shows in Apache's error logs. I have tried restarting the server with this module using both service httpd restart and httpd. These are the last few lines returned of strace httpd -X: gettimeofday({1292100295, 434487}, NULL) = 0 socket(PF_INET6, SOCK_STREAM, IPPROTO_IP) = -1 EAFNOSUPPORT (Address family not supported by protocol) socket(PF_NETLINK, SOCK_RAW, 0) = 3 bind(3, {sa_family=AF_NETLINK, pid=0, groups=00000000}, 12) = 0 getsockname(3, {sa_family=AF_NETLINK, pid=22378, groups=00000000}, [12]) = 0 time(NULL) = 1292100295 sendto(3, "\24\0\0\0\26\0\1\3\307\342\3M\0\0\0\0\0\305\333\267", 20, 0, {sa_family=AF_NETLINK, pid=0, groups=00000000}, 12) = 20 recvmsg(3, {msg_name(12)={sa_family=AF_NETLINK, pid=0, groups=00000000}, msg_iov(1)=[{"<\0\0\0\24\0\2\0\307\342\3MjW\0\0\2\10\200\376\1\0\0\0"..., 4096}], msg_controllen=0, msg_flags=0}, 0) = 664 recvmsg(3, {msg_name(12)={sa_family=AF_NETLINK, pid=0, groups=00000000}, msg_iov(1)=[{"\24\0\0\0\3\0\2\0\307\342\3MjW\0\0\0\0\0\0\1\0\0\0\10\0"..., 4096}], msg_controllen=0, msg_flags=0}, 0) = 20 close(3) = 0 socket(PF_INET, SOCK_STREAM, IPPROTO_IP) = 3 --- SIGSEGV (Segmentation fault) @ 0 (0) --- +++ killed by SIGSEGV +++ Process 22378 detached Has anyone had a similar problem using Apache 2.0.52 with mod_jk? I might try downloading and building the source for the Apache server and mod_jk myself if there isn't a discovered fix for this.

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• Shell command slow when using pipe, fast with intermediate file

  - by plang

  Does anyone understand this huge difference in processing time, when using an intermediate file, or when using a pipe? I'm converting tiff to pdf using standard tools on a fresh debian squeeze server. A standard way of doing this is to convert to ps first. Without pipe: root@web5:~# time tiff2ps test.tif > test.ps real 0m0.860s user 0m0.744s sys 0m0.112s root@web5:~# time ps2pdf13 -sPAPERSIZE=a4 test.ps > test.pdf real 0m0.667s user 0m0.612s sys 0m0.060s With pipe: root@web5:~# time tiff2ps test.tif | ps2pdf13 -sPAPERSIZE=a4 - > test.pdf real 1m6.098s user 0m15.861s sys 0m50.9 During the last command, gs process is at 100% all the time. Update: Here is an strace output for the ps generation: root@web5:~# strace tiff2ps test.tif > test.ps execve("/usr/bin/tiff2ps", ["tiff2ps", "test.tif"], [/* 28 vars */]) = 0 brk(0) = 0x1395000 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory) mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fb5a1937000 access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory) open("/etc/ld.so.cache", O_RDONLY) = 3 fstat(3, {st_mode=S_IFREG|0644, st_size=21735, ...}) = 0 mmap(NULL, 21735, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7fb5a1931000 close(3) = 0 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory) open("/usr/lib/libtiff.so.4", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\200\0\0\0\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0644, st_size=405128, ...}) = 0 mmap(NULL, 2501416, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7fb5a14b9000 mprotect(0x7fb5a151a000, 2093056, PROT_NONE) = 0 mmap(0x7fb5a1719000, 12288, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x60000) = 0x7fb5a1719000 close(3) = 0 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory) open("/usr/lib/libjpeg.so.62", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\3408\0\0\0\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0644, st_size=145048, ...}) = 0 mmap(NULL, 2240080, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7fb5a1296000 mprotect(0x7fb5a12b9000, 2093056, PROT_NONE) = 0 mmap(0x7fb5a14b8000, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x22000) = 0x7fb5a14b8000 close(3) = 0 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory) open("/usr/lib/libz.so.1", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\260\"\0\0\0\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0644, st_size=93936, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fb5a1930000 mmap(NULL, 2188976, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7fb5a107f000 mprotect(0x7fb5a1096000, 2093056, PROT_NONE) = 0 mmap(0x7fb5a1295000, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x16000) = 0x7fb5a1295000 close(3) = 0 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory) open("/lib/libm.so.6", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\360>\0\0\0\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0644, st_size=530736, ...}) = 0 mmap(NULL, 2625768, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7fb5a0dfd000 mprotect(0x7fb5a0e7d000, 2097152, PROT_NONE) = 0 mmap(0x7fb5a107d000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x80000) = 0x7fb5a107d000 close(3) = 0 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory) open("/lib/libc.so.6", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\240\355\1\0\0\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0755, st_size=1437064, ...}) = 0 mmap(NULL, 3545160, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7fb5a0a9b000 mprotect(0x7fb5a0bf4000, 2093056, PROT_NONE) = 0 mmap(0x7fb5a0df3000, 20480, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x158000) = 0x7fb5a0df3000 mmap(0x7fb5a0df8000, 18504, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7fb5a0df8000 close(3) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fb5a192f000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fb5a192e000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fb5a192d000 arch_prctl(ARCH_SET_FS, 0x7fb5a192e700) = 0 mprotect(0x7fb5a0df3000, 16384, PROT_READ) = 0 mprotect(0x7fb5a107d000, 4096, PROT_READ) = 0 mprotect(0x7fb5a1939000, 4096, PROT_READ) = 0 munmap(0x7fb5a1931000, 21735) = 0 open("test.tif", O_RDONLY) = 3 brk(0) = 0x1395000 brk(0x13b6000) = 0x13b6000 read(3, "II*\0\10\0\0\0", 8) = 8 fstat(3, {st_mode=S_IFREG|0644, st_size=1825656, ...}) = 0 mmap(NULL, 1825656, PROT_READ, MAP_SHARED, 3, 0) = 0x7fb5a176f000 open("/proc/meminfo", O_RDONLY) = 4 fstat(4, {st_mode=S_IFREG|0444, st_size=0, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fb5a1936000 read(4, "MemTotal: 2090844 kB\nMemF"..., 1024) = 1024 close(4) = 0 munmap(0x7fb5a1936000, 4096) = 0 write(2, "TIFFReadDirectory: ", 19TIFFReadDirectory: ) = 19 write(2, "Warning, ", 9Warning, ) = 9 write(2, "test.tif: wrong data type 7 for "..., 59test.tif: wrong data type 7 for "RichTIFFIPTC"; tag ignored) = 59 write(2, ".\n", 2. ) = 2 gettimeofday({1334836895, 374666}, NULL) = 0 fstat(1, {st_mode=S_IFREG|0664, st_size=0, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fb5a1936000 open("/etc/localtime", O_RDONLY) = 4 fstat(4, {st_mode=S_IFREG|0644, st_size=1892, ...}) = 0 fstat(4, {st_mode=S_IFREG|0644, st_size=1892, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fb5a1935000 read(4, "TZif2\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\4\0\0\0\4\0\0\0\0"..., 4096) = 1892 lseek(4, -1217, SEEK_CUR) = 675 read(4, "TZif2\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\6\0\0\0\6\0\0\0\0"..., 4096) = 1217 close(4) = 0 munmap(0x7fb5a1935000, 4096) = 0 write(1, "%!PS-Adobe-3.0 EPSF-3.0\n%%Creato"..., 4096) = 4096 write(1, "fffffffffffffffffffffffffffff\nff"..., 4096) = 4096 write(1, "ffffffffffffffffffff\nfffffffffff"..., 4096) = 4096 write(1, "fffffffffff\nffffffffffffffffffff"..., 4096) = 4096 write(1, "ff\nfffffffffffffffffffffffffffff"..., 4096) = 4096 write(1, "ffffffffffffffffffffffffffffffff"..., 4096) = 4096 write(1, "ffffffffffffffffffffffffffffffff"..., 4096) = 4096 write(1, "ffffffffffffffffffffffffffffffff"..., 4096) = 4096 write(1, "ffffffffffffffffffffffffffffffff"..., 4096) = 4096 write(1, "ffffffffffffffffffffffff\nfffffff"..., 4096) = 4096 Here is an strace output for the piped version: PS generation seems to be much slower when output is piped into ps2pdf13. root@web5:~# strace tiff2ps test.tif | ps2pdf13 -sPAPERSIZE=a4 - > test.pdf execve("/usr/bin/tiff2ps", ["tiff2ps", "test.tif"], [/* 28 vars */]) = 0 brk(0) = 0x1b97000 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory) mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f9208bb1000 access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory) open("/etc/ld.so.cache", O_RDONLY) = 3 fstat(3, {st_mode=S_IFREG|0644, st_size=21735, ...}) = 0 mmap(NULL, 21735, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f9208bab000 close(3) = 0 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory) open("/usr/lib/libtiff.so.4", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\200\0\0\0\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0644, st_size=405128, ...}) = 0 mmap(NULL, 2501416, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f9208733000 mprotect(0x7f9208794000, 2093056, PROT_NONE) = 0 mmap(0x7f9208993000, 12288, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x60000) = 0x7f9208993000 close(3) = 0 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory) open("/usr/lib/libjpeg.so.62", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\3408\0\0\0\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0644, st_size=145048, ...}) = 0 mmap(NULL, 2240080, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f9208510000 mprotect(0x7f9208533000, 2093056, PROT_NONE) = 0 mmap(0x7f9208732000, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x22000) = 0x7f9208732000 close(3) = 0 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory) open("/usr/lib/libz.so.1", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\260\"\0\0\0\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0644, st_size=93936, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f9208baa000 mmap(NULL, 2188976, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f92082f9000 mprotect(0x7f9208310000, 2093056, PROT_NONE) = 0 mmap(0x7f920850f000, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x16000) = 0x7f920850f000 close(3) = 0 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory) open("/lib/libm.so.6", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\360>\0\0\0\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0644, st_size=530736, ...}) = 0 mmap(NULL, 2625768, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f9208077000 mprotect(0x7f92080f7000, 2097152, PROT_NONE) = 0 mmap(0x7f92082f7000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x80000) = 0x7f92082f7000 close(3) = 0 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory) open("/lib/libc.so.6", O_RDONLY) = 3 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\240\355\1\0\0\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0755, st_size=1437064, ...}) = 0 mmap(NULL, 3545160, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f9207d15000 mprotect(0x7f9207e6e000, 2093056, PROT_NONE) = 0 mmap(0x7f920806d000, 20480, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x158000) = 0x7f920806d000 mmap(0x7f9208072000, 18504, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7f9208072000 close(3) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f9208ba9000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f9208ba8000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f9208ba7000 arch_prctl(ARCH_SET_FS, 0x7f9208ba8700) = 0 mprotect(0x7f920806d000, 16384, PROT_READ) = 0 mprotect(0x7f92082f7000, 4096, PROT_READ) = 0 mprotect(0x7f9208bb3000, 4096, PROT_READ) = 0 munmap(0x7f9208bab000, 21735) = 0 open("test.tif", O_RDONLY) = 3 brk(0) = 0x1b97000 brk(0x1bb8000) = 0x1bb8000 read(3, "II*\0\10\0\0\0", 8) = 8 fstat(3, {st_mode=S_IFREG|0644, st_size=1825656, ...}) = 0 mmap(NULL, 1825656, PROT_READ, MAP_SHARED, 3, 0) = 0x7f92089e9000 open("/proc/meminfo", O_RDONLY) = 4 fstat(4, {st_mode=S_IFREG|0444, st_size=0, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f9208bb0000 read(4, "MemTotal: 2090844 kB\nMemF"..., 1024) = 1024 close(4) = 0 munmap(0x7f9208bb0000, 4096) = 0 write(2, "TIFFReadDirectory: ", 19TIFFReadDirectory: ) = 19 write(2, "Warning, ", 9Warning, ) = 9 write(2, "test.tif: wrong data type 7 for "..., 59test.tif: wrong data type 7 for "RichTIFFIPTC"; tag ignored) = 59 write(2, ".\n", 2. ) = 2 gettimeofday({1334836513, 114140}, NULL) = 0 fstat(1, {st_mode=S_IFIFO|0600, st_size=0, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f9208bb0000 open("/etc/localtime", O_RDONLY) = 4 fstat(4, {st_mode=S_IFREG|0644, st_size=1892, ...}) = 0 fstat(4, {st_mode=S_IFREG|0644, st_size=1892, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f9208baf000 read(4, "TZif2\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\4\0\0\0\4\0\0\0\0"..., 4096) = 1892 lseek(4, -1217, SEEK_CUR) = 675 read(4, "TZif2\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\6\0\0\0\6\0\0\0\0"..., 4096) = 1217 close(4) = 0 munmap(0x7f9208baf000, 4096) = 0 write(1, "%!PS-Adobe-3.0 EPSF-3.0\n%%Creato"..., 4096) = 4096 write(1, "fffffffffffffffffffffffffffff\nff"..., 4096) = 4096 write(1, "ffffffffffffffffffff\nfffffffffff"..., 4096) = 4096 write(1, "fffffffffff\nffffffffffffffffffff"..., 4096) = 4096 write(1, "ff\nfffffffffffffffffffffffffffff"..., 4096) = 4096 write(1, "ffffffffffffffffffffffffffffffff"..., 4096) = 4096 write(1, "ffffffffffffffffffffffffffffffff"..., 4096) = 4096 write(1, "ffffffffffffffffffffffffffffffff"..., 4096) = 4096 write(1, "ffffffffffffffffffffffffffffffff"..., 4096) = 4096 ...etc...

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• Apache process consumes too much CPU

  - by Niro

  I have an ubuntu apache/php server running php doing appx 100 hits/sec and a PHP cron running in the background. I get occasionally high CPU load on one of the Apache processes which stays high regardless of traffic or cron activity. It seems to me that its stuck in some kind of loop or something. Below you will find the top and strace info. How can I find where the bad code is and what causes this? top - 14:45:24 up 3 days, 3:38, 1 user, load average: 5.10, 5.88, 5.85 Tasks: 163 total, 5 running, 158 sleeping, 0 stopped, 0 zombie Cpu(s): 47.8%us, 18.5%sy, 0.0%ni, 10.2%id, 0.0%wa, 0.0%hi, 1.8%si, 21.6%st Mem: 7885012k total, 3858484k used, 4026528k free, 177444k buffers Swap: 0k total, 0k used, 0k free, 1037868k cached PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 10736 www-data 20 0 769m 559m 478m R 69 7.3 29:08.30 apache2 10844 www-data 20 0 824m 601m 492m S 17 7.8 4:37.90 apache2 1016 root 20 0 242m 25m 4628 S 6 0.3 162:07.93 scalarizr 9030 www-data 20 0 879m 619m 492m S 4 8.0 5:06.82 apache2 20216 www-data 20 0 747m 228m 170m S 4 3.0 0:01.94 apache2 10807 www-data 20 0 814m 584m 492m S 3 7.6 4:54.10 apache2 10455 www-data 20 0 831m 574m 492m S 3 7.5 4:32.65 apache2 10495 www-data 20 0 849m 592m 492m S 3 7.7 4:41.10 apache2 10884 www-data 20 0 840m 581m 492m S 3 7.6 4:25.06 apache2 ^CProcess 10736 detached % time seconds usecs/call calls errors syscall ------ ----------- ----------- --------- --------- ---------------- 74.55 0.148052 1 109755 gettimeofday 25.36 0.050370 0 164634 clock_gettime 0.09 0.000178 0 54878 poll ------ ----------- ----------- --------- --------- ---------------- 100.00 0.198600 329267 total root@ec2-67-202-54-36:~# ^C

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• stdout, stderr, and what else? (going insane parsing slapadd output)

  - by user64204

  I am using slapadd to restore a backup. That backup contains 45k entries which takes a while to restore so I need to get some progress update from slapadd. Luckily for me there is the -v switch which gives an output similar to this one: added: "[email protected],ou=People,dc=example,dc=org" (00003d53) added: "[email protected],ou=People,dc=example,dc=org" (00003d54) added: "[email protected],ou=People,dc=example,dc=org" (00003d55) .######## 44.22% eta 05m05s elapsed 04m spd 29.2 k/s added: "[email protected],ou=People,dc=example,dc=org" (00003d56) added: "[email protected],ou=People,dc=example,dc=org" (00003d57) added: "[email protected],ou=People,dc=example,dc=org" (00003d58) added: "[email protected],ou=People,dc=example,dc=org" (00003d59) Every N entries added, slapadd writes a progress update output line (.######## 44.22% eta 05m05s elapsed ...) which I want to keep and an output line for every entry created which I want to hide because it exposes people's email address but still want to count them to know how many users were imported The way I thought about hiding emails and showing the progress update is this: $ slapadd -v ... 2>&1 | tee log.txt | grep '########' # => would give me real-time progress update $ grep "added" log.txt | wc -l # => once backup has been restored I would know how many users were added I tried different variations of the above, and whatever I try I can't grep the progress update output line. I traced slapadd as follows: sudo strace slapadd -v ... And here is what I get: write(2, "added: \"[email protected]"..., 78added: "[email protected],ou=People,dc=example,dc=org" (00000009) ) = 78 gettimeofday({1322645227, 253338}, NULL) = 0 _######## 44.22% eta 05m05s elapsed 04m spd 29.2 k/s ) = 80 write(2, "\n", 1 ) As you can see, the percentage line isn't sent to either stdout or stderr (FYI I have validated with known working and failing commands that 2 is stderr and 1 is stdout) Q1: Where is the progress update output line going? Q2: How can I grep on it while sending stderr to a file? Additional info: I'm running Openldap 2.4.21 on ubuntu server 10.04

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• Webserver max CPU when apache and MYSQL are ran together

  - by Tim

  This website has been running fine without issues, Recently it went down. After some investigation it looks like the combo of MYSQL and Apache bring the box to its knees. Apache can run find serving static web pages and MYSQL can run fine when the website isn't working. As soon as the website is enabled with SQL running the CPU on the box remains at 100%. Picture of the usage: http://i.stack.imgur.com/GG2NC.png I've checked the sql database for errors, tried tuning nearly every parameter in apache/sql's conf file for performance. The server is a redhat based box running the latest software packages. Any help/suggestions are welcome. Doing an strace on a high cpu apache process I see the following: read(14, "", 8192) = 0 close(14) = 0 socket(PF_FILE, SOCK_STREAM, 0) = 14 fcntl64(14, F_SETFL, O_RDONLY) = 0 fcntl64(14, F_GETFL) = 0x2 (flags O_RDWR) connect(14, {sa_family=AF_FILE, path="/var/lib/mysql/mysql.sock"...}, 110) = 0 setsockopt(14, SOL_SOCKET, SO_RCVTIMEO, "\2003\341\1\0\0\0\0", 8) = 0 setsockopt(14, SOL_SOCKET, SO_SNDTIMEO, "\2003\341\1\0\0\0\0", 8) = 0 setsockopt(14, SOL_IP, IP_TOS, [8], 4) = -1 EOPNOTSUPP (Operation not supported) setsockopt(14, SOL_SOCKET, SO_KEEPALIVE, [1], 4) = 0 Here is what I see from a mysql process: futex(0x86fc9a4, FUTEX_WAIT_PRIVATE, 39, NULL) = 0 futex(0x86fc734, FUTEX_WAIT_PRIVATE, 2, NULL) = 0 futex(0x86fc734, FUTEX_WAKE_PRIVATE, 1) = 0 gettimeofday({1301465020, 141613}, NULL) = 0 clock_gettime(CLOCK_REALTIME, {1301465020, 141699633}) = 0 futex(0x8707a64, FUTEX_WAIT_PRIVATE, 1, {4, 999913367}) = 0 futex(0x8707a40, FUTEX_WAIT_PRIVATE, 2, NULL) = 0 futex(0x8707a40, FUTEX_WAKE_PRIVATE, 1) = 0 exit_group(0) = ?

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• Microbenchmark showing process-switching faster than thread-switching; what's wrong?

  - by Yang

  I have two simple microbenchmarks trying to measure thread- and process-switching overheads, but the process-switching overhead. The code is living here, and r1667 is pasted below: https://assorted.svn.sourceforge.net/svnroot/assorted/sandbox/trunk/src/c/process_switch_bench.c // on zs, ~2.1-2.4us/switch #include <stdlib.h> #include <fcntl.h> #include <stdint.h> #include <stdio.h> #include <semaphore.h> #include <unistd.h> #include <sys/wait.h> #include <sys/types.h> #include <sys/time.h> #include <pthread.h> uint32_t COUNTER; pthread_mutex_t LOCK; pthread_mutex_t START; sem_t *s0, *s1, *s2; void * threads ( void * unused ) { // Wait till we may fire away sem_wait(s2); for (;;) { pthread_mutex_lock(&LOCK); pthread_mutex_unlock(&LOCK); COUNTER++; sem_post(s0); sem_wait(s1); } return 0; } int64_t timeInMS () { struct timeval t; gettimeofday(&t, NULL); return ( (int64_t)t.tv_sec * 1000 + (int64_t)t.tv_usec / 1000 ); } int main ( int argc, char ** argv ) { int64_t start; pthread_t t1; pthread_mutex_init(&LOCK, NULL); COUNTER = 0; s0 = sem_open("/s0", O_CREAT, 0022, 0); if (s0 == 0) { perror("sem_open"); exit(1); } s1 = sem_open("/s1", O_CREAT, 0022, 0); if (s1 == 0) { perror("sem_open"); exit(1); } s2 = sem_open("/s2", O_CREAT, 0022, 0); if (s2 == 0) { perror("sem_open"); exit(1); } int x, y, z; sem_getvalue(s0, &x); sem_getvalue(s1, &y); sem_getvalue(s2, &z); printf("%d %d %d\n", x, y, z); pid_t pid = fork(); if (pid) { pthread_create(&t1, NULL, threads, NULL); pthread_detach(t1); // Get start time and fire away start = timeInMS(); sem_post(s2); sem_post(s2); // Wait for about a second sleep(1); // Stop thread pthread_mutex_lock(&LOCK); // Find out how much time has really passed. sleep won't guarantee me that // I sleep exactly one second, I might sleep longer since even after being // woken up, it can take some time before I gain back CPU time. Further // some more time might have passed before I obtained the lock! int64_t time = timeInMS() - start; // Correct the number of thread switches accordingly COUNTER = (uint32_t)(((uint64_t)COUNTER * 2 * 1000) / time); printf("Number of process switches in about one second was %u\n", COUNTER); printf("roughly %f microseconds per switch\n", 1000000.0 / COUNTER); // clean up kill(pid, 9); wait(0); sem_close(s0); sem_close(s1); sem_unlink("/s0"); sem_unlink("/s1"); sem_unlink("/s2"); } else { if (1) { sem_t *t = s0; s0 = s1; s1 = t; } threads(0); // never return } return 0; } https://assorted.svn.sourceforge.net/svnroot/assorted/sandbox/trunk/src/c/thread_switch_bench.c // From <http://stackoverflow.com/questions/304752/how-to-estimate-the-thread-context-switching-overhead> // on zs, ~4-5us/switch; tried making COUNTER updated only by one thread, but no difference #include <stdlib.h> #include <stdint.h> #include <stdio.h> #include <pthread.h> #include <unistd.h> #include <sys/time.h> uint32_t COUNTER; pthread_mutex_t LOCK; pthread_mutex_t START; pthread_cond_t CONDITION; void * threads ( void * unused ) { // Wait till we may fire away pthread_mutex_lock(&START); pthread_mutex_unlock(&START); int first=1; pthread_mutex_lock(&LOCK); // If I'm not the first thread, the other thread is already waiting on // the condition, thus Ihave to wake it up first, otherwise we'll deadlock if (COUNTER > 0) { pthread_cond_signal(&CONDITION); first=0; } for (;;) { if (first) COUNTER++; pthread_cond_wait(&CONDITION, &LOCK); // Always wake up the other thread before processing. The other // thread will not be able to do anything as long as I don't go // back to sleep first. pthread_cond_signal(&CONDITION); } pthread_mutex_unlock(&LOCK); return 0; } int64_t timeInMS () { struct timeval t; gettimeofday(&t, NULL); return ( (int64_t)t.tv_sec * 1000 + (int64_t)t.tv_usec / 1000 ); } int main ( int argc, char ** argv ) { int64_t start; pthread_t t1; pthread_t t2; pthread_mutex_init(&LOCK, NULL); pthread_mutex_init(&START, NULL); pthread_cond_init(&CONDITION, NULL); pthread_mutex_lock(&START); COUNTER = 0; pthread_create(&t1, NULL, threads, NULL); pthread_create(&t2, NULL, threads, NULL); pthread_detach(t1); pthread_detach(t2); // Get start time and fire away start = timeInMS(); pthread_mutex_unlock(&START); // Wait for about a second sleep(1); // Stop both threads pthread_mutex_lock(&LOCK); // Find out how much time has really passed. sleep won't guarantee me that // I sleep exactly one second, I might sleep longer since even after being // woken up, it can take some time before I gain back CPU time. Further // some more time might have passed before I obtained the lock! int64_t time = timeInMS() - start; // Correct the number of thread switches accordingly COUNTER = (uint32_t)(((uint64_t)COUNTER * 2 * 1000) / time); printf("Number of thread switches in about one second was %u\n", COUNTER); printf("roughly %f microseconds per switch\n", 1000000.0 / COUNTER); return 0; }

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• is it possible to turn off vdso on glibc side?

  - by heroxbd

  I am aware that passing vdso=0 to kernel can turn this feature off, and that the dynamic linker in glibc can automatic detect and use vdso feature from kernel. Here I met with this problem. There is a RHEL 5.6 box (kernel 2.6.18-238.el5) in my institution where I only have a normal user access, probably suffering from RHEL bug 673616. As I compile a toolchain of linux-headers-3.9/gcc-4.7.2/glibc-2.17/binutils-2.23 on top of it, gcc bootstrap fails in cc1 in stage2 cannnot be run Program received signal SIGSEGV, Segmentation fault. 0x00002aaaaaaca6eb in ?? () (gdb) info sharedlibrary From To Syms Read Shared Object Library 0x00002aaaaaaabba0 0x00002aaaaaac3249 Yes (*) /home/benda/gnto/lib64/ld-linux-x86-64.so.2 0x00002aaaaacd29b0 0x00002aaaaace2480 Yes (*) /home/benda/gnto/usr/lib/libmpc.so.3 0x00002aaaaaef2cd0 0x00002aaaaaf36c08 Yes (*) /home/benda/gnto/usr/lib/libmpfr.so.4 0x00002aaaab14f280 0x00002aaaab19b658 Yes (*) /home/benda/gnto/usr/lib/libgmp.so.10 0x00002aaaab3b3060 0x00002aaaab3b3b50 Yes (*) /home/benda/gnto/lib/libdl.so.2 0x00002aaaab5b87b0 0x00002aaaab5c4bb0 Yes (*) /home/benda/gnto/usr/lib/libz.so.1 0x00002aaaab7d0e70 0x00002aaaab80f62c Yes (*) /home/benda/gnto/lib/libm.so.6 0x00002aaaaba70d40 0x00002aaaabb81aec Yes (*) /home/benda/gnto/lib/libc.so.6 (*): Shared library is missing debugging information. and a simple program #include <sys/time.h> #include <stdio.h> int main () { struct timeval tim; gettimeofday(&tim, NULL); return 0; } get segment fault in the same way if compiled against glibc-2.17 and xgcc from stage1. Both cc1 and the test program can be run on another running RHEL 5.5 (kernel 2.6.18-194.26.1.el5) with gcc-4.7.2/glibc-2.17/binutils-2.23 as normal user. I cannot simply upgrade the box to a newer RHEL version, nor could I turn VDSO off via sysctl or proc. The question is, is there a way to compile glibc so that it turns off VDSO unconditionally?

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• Where are possible locations of queueing/buffering delays in Linux multicast?

  - by Matt

  We make heavy use of multicasting messaging across many Linux servers on a LAN. We are seeing a lot of delays. We basically send an enormous number of small packages. We are more concerned with latency than throughput. The machines are all modern, multi-core (at least four, generally eight, 16 if you count hyperthreading) machines, always with a load of 2.0 or less, usually with a load less than 1.0. The networking hardware is also under 50% capacity. The delays we see look like queueing delays: the packets will quickly start increasing in latency, until it looks like they jam up, then return back to normal. The messaging structure is basically this: in the "sending thread", pull messages from a queue, add a timestamp (using gettimeofday()), then call send(). The receiving program receives the message, timestamps the receive time, and pushes it in a queue. In a separate thread, the queue is processed, analyzing the difference between sending and receiving timestamps. (Note that our internal queues are not part of the problem, since the timestamps are added outside of our internal queuing.) We don't really know where to start looking for an answer to this problem. We're not familiar with Linux internals. Our suspicion is that the kernel is queuing or buffering the packets, either on the send side or the receive side (or both). But we don't know how to track this down and trace it. For what it's worth, we're using CentOS 4.x (RHEL kernel 2.6.9).

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• Installing gtk-config and/or fsv in Ubuntu 10.10

  - by Wayne Werner

  Hi, I'm trying to install the File System Visualizer (think "It's a UNIX System! I know this!" from Jurassic Park) on Ubuntu 10.10. I've got the .tar.gz downloaded, and extracted. However, when I ./configure, I get this output: loading cache ./config.cache checking for a BSD compatible install... /usr/bin/install -c checking whether build environment is sane... yes checking whether make sets ${MAKE}... yes checking for working aclocal... found checking for working autoconf... found checking for working automake... found checking for working autoheader... found checking for working makeinfo... missing checking for gcc... gcc checking whether the C compiler (gcc ) works... yes checking whether the C compiler (gcc ) is a cross-compiler... no checking whether we are using GNU C... yes checking whether gcc accepts -g... yes checking how to run the C preprocessor... gcc -E checking for ranlib... ranlib checking for POSIXized ISC... no checking for dirent.h that defines DIR... yes checking for opendir in -ldir... no checking for ANSI C header files... yes checking whether time.h and sys/time.h may both be included... yes checking for strings.h... yes checking for sys/time.h... yes checking for unistd.h... yes checking for working const... yes checking for mode_t... yes checking for uid_t in sys/types.h... yes checking for pid_t... yes checking for size_t... yes checking for comparison_fn_t... yes checking for st_blocks in struct stat... yes checking whether struct tm is in sys/time.h or time.h... time.h checking for working alloca.h... yes checking for alloca... yes checking for working fnmatch... yes checking for strftime... yes checking for getcwd... yes checking for gettimeofday... yes checking for mktime... yes checking for strcspn... yes checking for strdup... yes checking for strspn... yes checking for strtod... yes checking for strtoul... yes checking for scandir... yes checking for inline... inline checking for off_t... yes checking for unistd.h... (cached) yes checking for getpagesize... yes checking for working mmap... yes checking for argz.h... yes checking for limits.h... yes checking for locale.h... yes checking for nl_types.h... yes checking for malloc.h... yes checking for string.h... yes checking for unistd.h... (cached) yes checking for sys/param.h... yes checking for getcwd... (cached) yes checking for munmap... yes checking for putenv... yes checking for setenv... yes checking for setlocale... yes checking for strchr... yes checking for strcasecmp... yes checking for strdup... (cached) yes checking for __argz_count... yes checking for __argz_stringify... yes checking for __argz_next... yes checking for stpcpy... yes checking for LC_MESSAGES... yes checking whether NLS is requested... yes checking whether included gettext is requested... no checking for libintl.h... yes checking for gettext in libc... yes checking for msgfmt... /usr/bin/msgfmt checking for dcgettext... yes checking for gmsgfmt... /usr/bin/msgfmt checking for xgettext... /usr/bin/xgettext checking for gtk-config... no checking for GTK - version >= 1.2.1... no *** The gtk-config script installed by GTK could not be found *** If GTK was installed in PREFIX, make sure PREFIX/bin is in *** your path, or set the GTK_CONFIG environment variable to the *** full path to gtk-config. configure: error: Cannot find proper GTK+ version Obviously it's looking for gtk-config. However, apparently it doesn't exist in the repos anymore. Then this post mentioned that gtkglarea solved their problem, as mentioned in this file. Of course that poster neatly forgets to mention exactly what and how gtkglarea solved their problem, and Google is mostly devoid of information on the problem. So I come here asking for help! I would like to install fsv, but it tells me gtk-config doesn't exist. How can I fix this problem in Ubuntu 10.10? Thanks!

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• Adjusting server-side tickrate dynamically

  - by Stuart Blackler

  I know nothing of game development/this site, so I apologise if this is completely foobar. Today I experimented with building a small game loop for a network game (think MW3, CSGO etc). I was wondering why they do not build in automatic rate adjustment based on server performance? Would it affect the client that much if the client knew this frame is based on this tickrate? Has anyone attempted this before? Here is what my noobish C++ brain came up with earlier. It will improve the tickrate if it has been stable for x ticks. If it "lags", the tickrate will be reduced down by y amount: // GameEngine.cpp : Defines the entry point for the console application. // #ifdef WIN32 #include <Windows.h> #else #include <sys/time.h> #include <ctime> #endif #include<iostream> #include <dos.h> #include "stdafx.h" using namespace std; UINT64 GetTimeInMs() { #ifdef WIN32 /* Windows */ FILETIME ft; LARGE_INTEGER li; /* Get the amount of 100 nano seconds intervals elapsed since January 1, 1601 (UTC) and copy it * to a LARGE_INTEGER structure. */ GetSystemTimeAsFileTime(&ft); li.LowPart = ft.dwLowDateTime; li.HighPart = ft.dwHighDateTime; UINT64 ret = li.QuadPart; ret -= 116444736000000000LL; /* Convert from file time to UNIX epoch time. */ ret /= 10000; /* From 100 nano seconds (10^-7) to 1 millisecond (10^-3) intervals */ return ret; #else /* Linux */ struct timeval tv; gettimeofday(&tv, NULL); uint64 ret = tv.tv_usec; /* Convert from micro seconds (10^-6) to milliseconds (10^-3) */ ret /= 1000; /* Adds the seconds (10^0) after converting them to milliseconds (10^-3) */ ret += (tv.tv_sec * 1000); return ret; #endif } int _tmain(int argc, _TCHAR* argv[]) { int sv_tickrate_max = 1000; // The maximum amount of ticks per second int sv_tickrate_min = 100; // The minimum amount of ticks per second int sv_tickrate_adjust = 10; // How much to de/increment the tickrate by int sv_tickrate_stable_before_increment = 1000; // How many stable ticks before we increase the tickrate again int sys_tickrate_current = sv_tickrate_max; // Always start at the highest possible tickrate for the best performance int counter_stable_ticks = 0; // How many ticks we have not lagged for UINT64 __startTime = GetTimeInMs(); int ticks = 100000; while(ticks > 0) { int maxTimeInMs = 1000 / sys_tickrate_current; UINT64 _startTime = GetTimeInMs(); // Long code here... cout << "."; UINT64 _timeTaken = GetTimeInMs() - _startTime; if(_timeTaken < maxTimeInMs) { Sleep(maxTimeInMs - _timeTaken); counter_stable_ticks++; if(counter_stable_ticks >= sv_tickrate_stable_before_increment) { // reset the stable # ticks counter counter_stable_ticks = 0; // make sure that we don't go over the maximum tickrate if(sys_tickrate_current + sv_tickrate_adjust <= sv_tickrate_max) { sys_tickrate_current += sv_tickrate_adjust; // let me know in console #DEBUG cout << endl << "Improving tickrate. New tickrate: " << sys_tickrate_current << endl; } } } else if(_timeTaken > maxTimeInMs) { cout << endl; if((sys_tickrate_current - sv_tickrate_adjust) > sv_tickrate_min) { sys_tickrate_current -= sv_tickrate_adjust; } else { if(sys_tickrate_current == sv_tickrate_min) { cout << "Please reduce sv_tickrate_min..." << endl; } else{ sys_tickrate_current = sv_tickrate_min; } } // let me know in console #DEBUG cout << "The server has lag. Reduced tickrate to: " << sys_tickrate_current << endl; } ticks--; } UINT64 __timeTaken = GetTimeInMs() - __startTime; cout << endl << endl << "Total time in ms: " << __timeTaken; cout << endl << "Ending tickrate: " << sys_tickrate_current; char test; cin >> test; return 0; }

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• Getting timing consistency in Linux

  - by Jim Hunziker

  I can't seem to get a simple program (with lots of memory access) to achieve consistent timing in Linux. I'm using a 2.6 kernel, and the program is being run on a dual-core processor with realtime priority. I'm trying to disable cache effects by declaring the memory arrays as volatile. Below are the results and the program. What are some possible sources of the outliers? Results: Number of trials: 100 Range: 0.021732s to 0.085596s Average Time: 0.058094s Standard Deviation: 0.006944s Extreme Outliers (2 SDs away from mean): 7 Average Time, excluding extreme outliers: 0.059273s Program: #include <stdio.h> #include <stdlib.h> #include <math.h> #include <sched.h> #include <sys/time.h> #define NUM_POINTS 5000000 #define REPS 100 unsigned long long getTimestamp() { unsigned long long usecCount; struct timeval timeVal; gettimeofday(&timeVal, 0); usecCount = timeVal.tv_sec * (unsigned long long) 1000000; usecCount += timeVal.tv_usec; return (usecCount); } double convertTimestampToSecs(unsigned long long timestamp) { return (timestamp / (double) 1000000); } int main(int argc, char* argv[]) { unsigned long long start, stop; double times[REPS]; double sum = 0; double scale, avg, newavg, median; double stddev = 0; double maxval = -1.0, minval = 1000000.0; int i, j, freq, count; int outliers = 0; struct sched_param sparam; sched_getparam(getpid(), &sparam); sparam.sched_priority = sched_get_priority_max(SCHED_FIFO); sched_setscheduler(getpid(), SCHED_FIFO, &sparam); volatile float* data; volatile float* results; data = calloc(NUM_POINTS, sizeof(float)); results = calloc(NUM_POINTS, sizeof(float)); for (i = 0; i < REPS; ++i) { start = getTimestamp(); for (j = 0; j < NUM_POINTS; ++j) { results[j] = data[j]; } stop = getTimestamp(); times[i] = convertTimestampToSecs(stop-start); } free(data); free(results); for (i = 0; i < REPS; i++) { sum += times[i]; if (times[i] > maxval) maxval = times[i]; if (times[i] < minval) minval = times[i]; } avg = sum/REPS; for (i = 0; i < REPS; i++) stddev += (times[i] - avg)*(times[i] - avg); stddev /= REPS; stddev = sqrt(stddev); for (i = 0; i < REPS; i++) { if (times[i] > avg + 2*stddev || times[i] < avg - 2*stddev) { sum -= times[i]; outliers++; } } newavg = sum/(REPS-outliers); printf("Number of trials: %d\n", REPS); printf("Range: %fs to %fs\n", minval, maxval); printf("Average Time: %fs\n", avg); printf("Standard Deviation: %fs\n", stddev); printf("Extreme Outliers (2 SDs away from mean): %d\n", outliers); printf("Average Time, excluding extreme outliers: %fs\n", newavg); return 0; }

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• Confusion related to sigwait in multiprocess system

  - by user34790

  I am having difficulty in understanding IPC in multiprocess system. I have this system where there are three child processes that send two types of signals to their process group. There are four types of signal handling processes responsible for a particular type of signal. There is this monitoring process which waits for both the signals and then processes accordingly. When I run this program for a while, the monitoring process doesn't seem to pick up the signal as well as the signal handling process. I could see in the log that the signal is only being generated but not handled at all. My code is given below #include <cstdlib> #include <iostream> #include <iomanip> #include <unistd.h> #include <sys/types.h> #include <sys/wait.h> #include <sys/time.h> #include <signal.h> #include <unistd.h> #include <fcntl.h> #include <cstdio> #include <stdlib.h> #include <stdio.h> #include <pthread.h> using namespace std; double timestamp() { struct timeval tp; gettimeofday(&tp, NULL); return (double)tp.tv_sec + tp.tv_usec / 1000000.; } double getinterval() { srand(time(NULL)); int r = rand()%10 + 1; double s = (double)r/100; } int count; int count_1; int count_2; double time_1[10]; double time_2[10]; pid_t senders[1]; pid_t handlers[4]; pid_t reporter; void catcher(int sig) { printf("Signal catcher called for %d",sig); } int main(int argc, char *argv[]) { void signal_catcher_int(int); pid_t pid,w; int status; if(signal(SIGUSR1, SIG_IGN) == SIG_ERR) { perror("1"); return 1; } if(signal(SIGUSR2 ,SIG_IGN) == SIG_ERR) { perror("2"); return 2; } if(signal(SIGINT,signal_catcher_int) == SIG_ERR) { perror("3"); return 2; } //Registering the signal handler for(int i=0; i<4; i++) { if((pid = fork()) == 0) { cout << i << endl; //struct sigaction sigact; sigset_t sigset; int sig; int result = 0; sigemptyset(&sigset); if(i%2 == 0) { if(signal(SIGUSR2, SIG_IGN) == SIG_ERR) { perror("2"); return 2; } sigaddset(&sigset, SIGUSR1); sigprocmask(SIG_BLOCK, &sigset, NULL); } else { if(signal(SIGUSR1, SIG_IGN) == SIG_ERR) { perror("2"); return 2; } sigaddset(&sigset, SIGUSR2); sigprocmask(SIG_BLOCK, &sigset, NULL); } while(true) { int result = sigwait(&sigset, &sig); if(result == 0) { cout << "The caught signal is " << sig << endl; } } exit(0); } else { cout << "Registerd the handler " << pid << endl; handlers[i] = pid; } } //Registering the monitoring process if((pid = fork()) == 0) { sigset_t sigset; int sig; int result = 0; sigemptyset(&sigset); sigaddset(&sigset, SIGUSR1); sigaddset(&sigset, SIGUSR2); sigprocmask(SIG_BLOCK, &sigset, NULL); while(true) { int result = sigwait(&sigset, &sig); if(result == 0) { cout << "The monitored signal is " << sig << endl; } else { cout << "error" << endl; } } } else { reporter = pid; } sleep(3); //Registering the signal generator for(int i=0; i<1; i++) { if((pid = fork()) == 0) { if(signal(SIGUSR1, SIG_IGN) == SIG_ERR) { perror("1"); return 1; } if(signal(SIGUSR2, SIG_IGN) == SIG_ERR) { perror("2"); return 2; } srand(time(0)); while(true) { volatile int signal_id = rand()%2 + 1; cout << "Generating the signal " << signal_id << endl; if(signal_id == 1) { killpg(getpgid(getpid()), SIGUSR1); } else { killpg(getpgid(getpid()), SIGUSR2); } int r = rand()%10 + 1; double s = (double)r/100; sleep(s); } exit(0); } else { cout << "Registered the sender " << pid << endl; senders[i] = pid; } } while(w = wait(&status)) { cout << "Wait on PID " << w << endl; } } void signal_catcher_int(int the_sig) { //cout << "Handling the Ctrl C signal " << endl; for(int i=0; i<1; i++) { kill(senders[i],SIGKILL); } for(int i=0; i<4; i++) { kill(handlers[i],SIGKILL); } kill(reporter,SIGKILL); exit(3); } Any suggestions? Here is a sample of the output as well In the beginning Registerd the handler 9544 Registerd the handler 9545 1 Registerd the handler 9546 Registerd the handler 9547 2 3 0 Registered the sender 9550 Generating the signal 1 The caught signal is 10 The monitored signal is 10 The caught signal is 10 Generating the signal 1 The caught signal is 10 The monitored signal is 10 The caught signal is 10 Generating the signal 1 The caught signal is 10 The monitored signal is 10 The caught signal is 10 Generating the signal 1 The caught signal is 10 The monitored signal is 10 The caught signal is 10 Generating the signal 2 The caught signal is 12 The caught signal is 12 The monitored signal is 12 Generating the signal 2 Generating the signal 2 The caught signal is 12 The caught signal is 12 Generating the signal 1 The caught signal is 12 The monitored signal is 10 The monitored signal is 12 Generating the signal 1 Generating the signal 2 The caught signal is 12 Generating the signal 1 Generating the signal 2 10 The monitored signal is 10 The caught signal is 12 Generating the signal 1 The caught signal is 12 The monitored signal is GenThe caught signal is TheThe caught signal is 10 Generating the signal 2 Later on The monitored signal is GenThe monitored signal is 10 Generating the signal 1 Generating the signal 2 The caught signal is 10 The caught signal is 10 The caught signal is 10 The caught signal is 12 Generating the signal 1 Generating the signal 2 Generating the signal 1 Generating the signal 1 Generating the signal 2 Generating the signal 2 Generating the signal 2 Generating the signal 2 Generating the signal 2 Generating the signal 1 The caught signal is 12 The caught signal is 10 The caught signal is 10 Generating the signal 2 Generating the signal 1 Generating the signal 1 Generating the signal 2 Generating the signal 1 Generating the signal 2 Generating the signal 2 Generating the signal 2 Generating the signal 1 Generating the signal 2 Generating the signal 1 Generating the signal 2 Generating the signal 2 The caught signal is 10 Generating the signal 2 Generating the signal 1 Generating the signal 1 As you can see initially, the signal was generated and handled both by my signal handlers and monitoring processes. But later on the signal was generated a lot, but it was not quite processes in the same magnitude as before. Further I could see very less signal processing by the monitoring process Can anyone please provide some insights. What's going on?

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• How to install SpatiaLite 3 on 12.04

  - by Terra

  1) sudo apt-get install libsqlite3-dev libgeos-dev 2) libspatialite-3.0.0-stable$ ./configure Result: configure: error: cannot find proj_api.h, bailing out checking for a BSD-compatible install... /usr/bin/install -c checking whether build environment is sane... yes checking for a thread-safe mkdir -p... /bin/mkdir -p checking for gawk... no checking for mawk... mawk checking whether make sets $(MAKE)... yes checking whether to enable maintainer-specific portions of Makefiles... no checking for style of include used by make... GNU checking for gcc... gcc checking whether the C compiler works... yes checking for C compiler default output file name... a.out checking for suffix of executables... checking whether we are cross compiling... no checking for suffix of object files... o checking whether we are using the GNU C compiler... yes checking whether gcc accepts -g... yes checking for gcc option to accept ISO C89... none needed checking dependency style of gcc... gcc3 checking how to run the C preprocessor... gcc -E checking for grep that handles long lines and -e... /bin/grep checking for egrep... /bin/grep -E checking for ANSI C header files... yes checking for sys/types.h... yes checking for sys/stat.h... yes checking for stdlib.h... yes checking for string.h... yes checking for memory.h... yes checking for strings.h... yes checking for inttypes.h... yes checking for stdint.h... yes checking for unistd.h... yes checking for stdlib.h... (cached) yes checking stdio.h usability... yes checking stdio.h presence... yes checking for stdio.h... yes checking for string.h... (cached) yes checking for memory.h... (cached) yes checking math.h usability... yes checking math.h presence... yes checking for math.h... yes checking float.h usability... yes checking float.h presence... yes checking for float.h... yes checking fcntl.h usability... yes checking fcntl.h presence... yes checking for fcntl.h... yes checking for inttypes.h... (cached) yes checking stddef.h usability... yes checking stddef.h presence... yes checking for stddef.h... yes checking for stdint.h... (cached) yes checking sys/time.h usability... yes checking sys/time.h presence... yes checking for sys/time.h... yes checking for unistd.h... (cached) yes checking sqlite3.h usability... yes checking sqlite3.h presence... yes checking for sqlite3.h... yes checking sqlite3ext.h usability... yes checking sqlite3ext.h presence... yes checking for sqlite3ext.h... yes checking for g++... no checking for c++... no checking for gpp... no checking for aCC... no checking for CC... no checking for cxx... no checking for cc++... no checking for cl.exe... no checking for FCC... no checking for KCC... no checking for RCC... no checking for xlC_r... no checking for xlC... no checking whether we are using the GNU C++ compiler... no checking whether g++ accepts -g... no checking dependency style of g++... none checking for gcc... (cached) gcc checking whether we are using the GNU C compiler... (cached) yes checking whether gcc accepts -g... (cached) yes checking for gcc option to accept ISO C89... (cached) none needed checking dependency style of gcc... (cached) gcc3 checking how to run the C preprocessor... gcc -E checking whether ln -s works... yes checking whether make sets $(MAKE)... (cached) yes checking build system type... i686-pc-linux-gnu checking host system type... i686-pc-linux-gnu checking how to print strings... printf checking for a sed that does not truncate output... /bin/sed checking for fgrep... /bin/grep -F checking for ld used by gcc... /usr/bin/ld checking if the linker (/usr/bin/ld) is GNU ld... yes checking for BSD- or MS-compatible name lister (nm)... /usr/bin/nm -B checking the name lister (/usr/bin/nm -B) interface... BSD nm checking the maximum length of command line arguments... 1572864 checking whether the shell understands some XSI constructs... yes checking whether the shell understands "+="... yes checking how to convert i686-pc-linux-gnu file names to i686-pc-linux-gnu format... func_convert_file_noop checking how to convert i686-pc-linux-gnu file names to toolchain format... func_convert_file_noop checking for /usr/bin/ld option to reload object files... -r checking for objdump... objdump checking how to recognize dependent libraries... pass_all checking for dlltool... dlltool checking how to associate runtime and link libraries... printf %s\n checking for ar... ar checking for archiver @FILE support... @ checking for strip... strip checking for ranlib... ranlib checking command to parse /usr/bin/nm -B output from gcc object... ok checking for sysroot... no checking for mt... mt checking if mt is a manifest tool... no checking for dlfcn.h... yes checking for objdir... .libs checking if gcc supports -fno-rtti -fno-exceptions... no checking for gcc option to produce PIC... -fPIC -DPIC checking if gcc PIC flag -fPIC -DPIC works... yes checking if gcc static flag -static works... yes checking if gcc supports -c -o file.o... yes checking if gcc supports -c -o file.o... (cached) yes checking whether the gcc linker (/usr/bin/ld) supports shared libraries... yes checking whether -lc should be explicitly linked in... no checking dynamic linker characteristics... GNU/Linux ld.so checking how to hardcode library paths into programs... immediate checking whether stripping libraries is possible... yes checking if libtool supports shared libraries... yes checking whether to build shared libraries... yes checking whether to build static libraries... yes checking for an ANSI C-conforming const... yes checking for off_t... yes checking for size_t... yes checking whether time.h and sys/time.h may both be included... yes checking whether struct tm is in sys/time.h or time.h... time.h checking for working volatile... yes checking whether lstat correctly handles trailing slash... yes checking whether lstat accepts an empty string... no checking whether lstat correctly handles trailing slash... (cached) yes checking for working memcmp... yes checking whether stat accepts an empty string... no checking for strftime... yes checking for memset... yes checking for sqrt... no checking for strcasecmp... yes checking for strerror... yes checking for strncasecmp... yes checking for strstr... yes checking for fdatasync... yes checking for ftruncate... yes checking for getcwd... yes checking for gettimeofday... yes checking for localtime_r... yes checking for memmove... yes checking for strerror... (cached) yes checking for sqlite3_prepare_v2 in -lsqlite3... yes checking for sqlite3_rtree_geometry_callback in -lsqlite3... yes checking proj_api.h usability... no checking proj_api.h presence... no checking for proj_api.h... no configure: error: cannot find proj_api.h, bailing out

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• Package libxul not fount - Kiwix Wikpedia in Ubuntu Precise 12.04

  - by JHOSmAN

  I'm trying to install the service Kiwix but I need a library that is not available for Ubuntu 12.04 LTS Precise leave the log and if someone could tell me how to install Seller would appreciate. kiwix-0.9# ls aclocal.m4 COMPILE config.sub COPYING install-sh ltmain.sh missing static AUTHORS config.guess configure depcomp kiwix Makefile.am README CHANGELOG config.log configure.ac desktop libxul-dev_1.8.1.16+nobinonly-0ubuntu1_all.deb Makefile.in src root@ubuntu-MM061:/home/ubuntu/Escritorio/kiwix-0.9# ./configure checking for a BSD-compatible install... /usr/bin/install -c checking whether build environment is sane... yes checking for a thread-safe mkdir -p... /bin/mkdir -p checking for gawk... no checking for mawk... mawk checking whether make sets $(MAKE)... yes checking whether to enable maintainer-specific portions of Makefiles... no checking for gcc... gcc checking whether the C compiler works... yes checking for C compiler default output file name... a.out checking for suffix of executables... checking whether we are cross compiling... no checking for suffix of object files... o checking whether we are using the GNU C compiler... yes checking whether gcc accepts -g... yes checking for gcc option to accept ISO C89... none needed checking for style of include used by make... GNU checking dependency style of gcc... gcc3 checking for g++... g++ checking whether we are using the GNU C++ compiler... yes checking whether g++ accepts -g... yes checking dependency style of g++... gcc3 checking for g++... g++ checking for cl... no checking for cl... no checking for Xcode... no checking for jar... jar checking build system type... i686-pc-linux-gnu checking host system type... i686-pc-linux-gnu checking for a sed that does not truncate output... /bin/sed checking for grep that handles long lines and -e... /bin/grep checking for egrep... /bin/grep -E checking for fgrep... /bin/grep -F checking for ld used by gcc... /usr/bin/ld checking if the linker (/usr/bin/ld) is GNU ld... yes checking for BSD- or MS-compatible name lister (nm)... /usr/bin/nm -B checking the name lister (/usr/bin/nm -B) interface... BSD nm checking whether ln -s works... yes checking the maximum length of command line arguments... 1572864 checking whether the shell understands some XSI constructs... yes checking whether the shell understands "+="... yes checking for /usr/bin/ld option to reload object files... -r checking for objdump... objdump checking how to recognize dependent libraries... pass_all checking for ar... ar checking for strip... strip checking for ranlib... ranlib checking command to parse /usr/bin/nm -B output from gcc object... ok checking how to run the C preprocessor... gcc -E checking for ANSI C header files... yes checking for sys/types.h... yes checking for sys/stat.h... yes checking for stdlib.h... yes checking for string.h... yes checking for memory.h... yes checking for strings.h... yes checking for inttypes.h... yes checking for stdint.h... yes checking for unistd.h... yes checking for dlfcn.h... yes checking whether we are using the GNU C++ compiler... (cached) yes checking whether g++ accepts -g... (cached) yes checking dependency style of g++... (cached) gcc3 checking how to run the C++ preprocessor... g++ -E checking for objdir... .libs checking if gcc supports -fno-rtti -fno-exceptions... no checking for gcc option to produce PIC... -fPIC -DPIC checking if gcc PIC flag -fPIC -DPIC works... yes checking if gcc static flag -static works... yes checking if gcc supports -c -o file.o... yes checking if gcc supports -c -o file.o... (cached) yes checking whether the gcc linker (/usr/bin/ld) supports shared libraries... yes checking whether -lc should be explicitly linked in... no checking dynamic linker characteristics... GNU/Linux ld.so checking how to hardcode library paths into programs... immediate checking whether stripping libraries is possible... yes checking if libtool supports shared libraries... yes checking whether to build shared libraries... yes checking whether to build static libraries... yes checking for ld used by g++... /usr/bin/ld checking if the linker (/usr/bin/ld) is GNU ld... yes checking whether the g++ linker (/usr/bin/ld) supports shared libraries... yes checking for g++ option to produce PIC... -fPIC -DPIC checking if g++ PIC flag -fPIC -DPIC works... yes checking if g++ static flag -static works... yes checking if g++ supports -c -o file.o... yes checking if g++ supports -c -o file.o... (cached) yes checking whether the g++ linker (/usr/bin/ld) supports shared libraries... yes checking dynamic linker characteristics... GNU/Linux ld.so checking how to hardcode library paths into programs... immediate checking for ranlib... (cached) ranlib checking whether make sets $(MAKE)... (cached) yes checking for pkg-config... pkg-config checking for perl... perl checking fcntl.h usability... yes checking fcntl.h presence... yes checking for fcntl.h... yes checking float.h usability... yes checking float.h presence... yes checking for float.h... yes checking libintl.h usability... yes checking libintl.h presence... yes checking for libintl.h... yes checking limits.h usability... yes checking limits.h presence... yes checking for limits.h... yes checking stddef.h usability... yes checking stddef.h presence... yes checking for stddef.h... yes checking for stdint.h... (cached) yes checking for stdlib.h... (cached) yes checking for string.h... (cached) yes checking for strings.h... (cached) yes checking sys/socket.h usability... yes checking sys/socket.h presence... yes checking for sys/socket.h... yes checking sys/time.h usability... yes checking sys/time.h presence... yes checking for sys/time.h... yes checking for unistd.h... (cached) yes checking wchar.h usability... yes checking wchar.h presence... yes checking for wchar.h... yes checking for stdbool.h that conforms to C99... yes checking for _Bool... no checking for inline... inline checking for int16_t... yes checking for int32_t... yes checking for int64_t... yes checking for int8_t... yes checking for off_t... yes checking for pid_t... yes checking for size_t... yes checking for uint16_t... yes checking for uint32_t... yes checking for uint64_t... yes checking for uint8_t... yes checking for ptrdiff_t... yes checking vfork.h usability... no checking vfork.h presence... no checking for vfork.h... no checking for fork... yes checking for vfork... yes checking for working fork... yes checking for working vfork... (cached) yes checking for stdlib.h... (cached) yes checking for GNU libc compatible malloc... yes checking for working strtod... yes checking for getcwd... yes checking for gettimeofday... yes checking for memmove... yes checking for memset... yes checking for pow... yes checking for regcomp... yes checking for sqrt... yes checking for strcasecmp... yes checking for strchr... yes checking for strdup... yes checking for strerror... yes checking for strtol... yes Package libxul was not found in the pkg-config search path. Perhaps you should add the directory containing libxul.pc' to the PKG_CONFIG_PATH environment variable No package 'libxul' found Package libxul was not found in the pkg-config search path. Perhaps you should add the directory containinglibxul.pc' to the PKG_CONFIG_PATH environment variable No package 'libxul' found checking for /stable... no checking for "/nsISupports.idl"... no configure: error: unable to find nsISupports.idl apt-get install libxul Leyendo lista de paquetes... Hecho Creando árbol de dependencias Leyendo la información de estado... Hecho E: No se ha podido localizar el paquete libxul

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• Issues with signal handling [closed]

  - by user34790

  I am trying to actually study the signal handling behavior in multiprocess system. I have a system where there are three signal generating processes generating signals of type SIGUSR1 and SIGUSR1. I have two handler processes that handle a particular type of signal. I have another monitoring process that also receives the signals and then does its work. I have a certain issue. Whenever my signal handling processes generate a signal of a particular type, it is sent to the process group so it is received by the signal handling processes as well as the monitoring processes. Whenever the signal handlers of monitoring and signal handling processes are called, I have printed to indicate the signal handling. I was expecting a uniform series of calls for the signal handlers of the monitoring and handling processes. However, looking at the output I could see like at the beginning the monitoring and signal handling processes's signal handlers are called uniformly. However, after I could see like signal handler processes handlers being called in a burst followed by the signal handler of monitoring process being called in a burst. Here is my code and output #include <iostream> #include <sys/types.h> #include <sys/wait.h> #include <sys/time.h> #include <signal.h> #include <cstdio> #include <stdlib.h> #include <sys/ipc.h> #include <sys/shm.h> #define NUM_SENDER_PROCESSES 3 #define NUM_HANDLER_PROCESSES 4 #define NUM_SIGNAL_REPORT 10 #define MAX_SIGNAL_COUNT 100000 using namespace std; volatile int *usrsig1_handler_count; volatile int *usrsig2_handler_count; volatile int *usrsig1_sender_count; volatile int *usrsig2_sender_count; volatile int *lock_1; volatile int *lock_2; volatile int *lock_3; volatile int *lock_4; volatile int *lock_5; volatile int *lock_6; //Used only by the monitoring process volatile int monitor_count; volatile int usrsig1_monitor_count; volatile int usrsig2_monitor_count; double time_1[NUM_SIGNAL_REPORT]; double time_2[NUM_SIGNAL_REPORT]; //Used only by the main process int total_signal_count; //For shared memory int shmid; const int shareSize = sizeof(int) * (10); double timestamp() { struct timeval tp; gettimeofday(&tp, NULL); return (double)tp.tv_sec + tp.tv_usec / 1000000.; } pid_t senders[NUM_SENDER_PROCESSES]; pid_t handlers[NUM_HANDLER_PROCESSES]; pid_t reporter; void signal_catcher_1(int); void signal_catcher_2(int); void signal_catcher_int(int); void signal_catcher_monitor(int); void signal_catcher_main(int); void terminate_processes() { //Kill the child processes int status; cout << "Time up terminating the child processes" << endl; for(int i=0; i<NUM_SENDER_PROCESSES; i++) { kill(senders[i],SIGKILL); } for(int i=0; i<NUM_HANDLER_PROCESSES; i++) { kill(handlers[i],SIGKILL); } kill(reporter,SIGKILL); //Wait for the child processes to finish for(int i=0; i<NUM_SENDER_PROCESSES; i++) { waitpid(senders[i], &status, 0); } for(int i=0; i<NUM_HANDLER_PROCESSES; i++) { waitpid(handlers[i], &status, 0); } waitpid(reporter, &status, 0); } int main(int argc, char *argv[]) { if(argc != 2) { cout << "Required parameters missing. " << endl; cout << "Option 1 = 1 which means run for 30 seconds" << endl; cout << "Option 2 = 2 which means run until 100000 signals" << endl; exit(0); } int option = atoi(argv[1]); pid_t pid; if(option == 2) { if(signal(SIGUSR1, signal_catcher_main) == SIG_ERR) { perror("1"); exit(1); } if(signal(SIGUSR2, signal_catcher_main) == SIG_ERR) { perror("2"); exit(1); } } else { if(signal(SIGUSR1, SIG_IGN) == SIG_ERR) { perror("1"); exit(1); } if(signal(SIGUSR2, SIG_IGN) == SIG_ERR) { perror("2"); exit(1); } } if(signal(SIGINT, signal_catcher_int) == SIG_ERR) { perror("3"); exit(1); } /////////////////////////////////////////////////////////////////////////////////////// ////////////////////// Initializing the shared memory ///////////////////////////////// /////////////////////////////////////////////////////////////////////////////////////// cout << "Initializing the shared memory" << endl; if ((shmid=shmget(IPC_PRIVATE,shareSize,IPC_CREAT|0660))< 0) { perror("shmget fail"); exit(1); } usrsig1_handler_count = (int *) shmat(shmid, NULL, 0); usrsig2_handler_count = usrsig1_handler_count + 1; usrsig1_sender_count = usrsig2_handler_count + 1; usrsig2_sender_count = usrsig1_sender_count + 1; lock_1 = usrsig2_sender_count + 1; lock_2 = lock_1 + 1; lock_3 = lock_2 + 1; lock_4 = lock_3 + 1; lock_5 = lock_4 + 1; lock_6 = lock_5 + 1; //Initialize them to be zero *usrsig1_handler_count = 0; *usrsig2_handler_count = 0; *usrsig1_sender_count = 0; *usrsig2_sender_count = 0; *lock_1 = 0; *lock_2 = 0; *lock_3 = 0; *lock_4 = 0; *lock_5 = 0; *lock_6 = 0; cout << "End of initializing the shared memory" << endl; ///////////////////////////////////////////////////////////////////////////////////////////// /////////////////// End of initializing the shared memory /////////////////////////////////// ///////////////////////////////////////////////////////////////////////////////////////////// /////////////////////////////////////////////////////////////////////////////////////////// /////////////////////////////Registering the signal handlers/////////////////////////////// /////////////////////////////////////////////////////////////////////////////////////////// cout << "Registering the signal handlers" << endl; for(int i=0; i<NUM_HANDLER_PROCESSES; i++) { if((pid = fork()) == 0) { if(i%2 == 0) { struct sigaction action; action.sa_handler = signal_catcher_1; sigset_t block_mask; action.sa_flags = 0; sigaction(SIGUSR1,&action,NULL); if(signal(SIGUSR2, SIG_IGN) == SIG_ERR) { perror("2"); exit(1); } } else { if(signal(SIGUSR1 ,SIG_IGN) == SIG_ERR) { perror("1"); exit(1); } struct sigaction action; action.sa_handler = signal_catcher_2; action.sa_flags = 0; sigaction(SIGUSR2,&action,NULL); } if(signal(SIGINT, SIG_DFL) == SIG_ERR) { perror("2"); exit(1); } while(true) { pause(); } exit(0); } else { //cout << "Registerd the handler " << pid << endl; handlers[i] = pid; } } cout << "End of registering the signal handlers" << endl; ///////////////////////////////////////////////////////////////////////////////////////////////////// ////////////////////////////End of registering the signal handlers ////////////////////////////////// ///////////////////////////////////////////////////////////////////////////////////////////////////// //////////////////////////////////////////////////////////////////////////////////////////////////// ///////////////////////////Registering the monitoring process ////////////////////////////////////// //////////////////////////////////////////////////////////////////////////////////////////////////// cout << "Registering the monitoring process" << endl; if((pid = fork()) == 0) { struct sigaction action; action.sa_handler = signal_catcher_monitor; sigemptyset(&action.sa_mask); sigset_t block_mask; sigemptyset(&block_mask); sigaddset(&block_mask,SIGUSR1); sigaddset(&block_mask,SIGUSR2); action.sa_flags = 0; action.sa_mask = block_mask; sigaction(SIGUSR1,&action,NULL); sigaction(SIGUSR2,&action,NULL); if(signal(SIGINT, SIG_DFL) == SIG_ERR) { perror("2"); exit(1); } while(true) { pause(); } exit(0); } else { cout << "Monitor's pid is " << pid << endl; reporter = pid; } cout << "End of registering the monitoring process" << endl; ///////////////////////////////////////////////////////////////////////////////////////////////////// ////////////////////////End of registering the monitoring process//////////////////////////////////// ///////////////////////////////////////////////////////////////////////////////////////////////////// //Sleep to make sure that the monitor and handler processes are well initialized and ready to handle signals sleep(5); ////////////////////////////////////////////////////////////////////////////////////////////////////// //////////////////////////Registering the signal generators/////////////////////////////////////////// ///////////////////////////////////////////////////////////////////////////////////////////////////// cout << "Registering the signal generators" << endl; for(int i=0; i<NUM_SENDER_PROCESSES; i++) { if((pid = fork()) == 0) { if(signal(SIGUSR1, SIG_IGN) == SIG_ERR) { perror("1"); exit(1); } if(signal(SIGUSR2, SIG_IGN) == SIG_ERR) { perror("2"); exit(1); } if(signal(SIGINT, SIG_DFL) == SIG_ERR) { perror("2"); exit(1); } srand(i); while(true) { int signal_id = rand()%2 + 1; if(signal_id == 1) { killpg(getpgid(getpid()), SIGUSR1); while(__sync_lock_test_and_set(lock_4,1) != 0) { } (*usrsig1_sender_count)++; *lock_4 = 0; } else { killpg(getpgid(getpid()), SIGUSR2); while(__sync_lock_test_and_set(lock_5,1) != 0) { } (*usrsig2_sender_count)++; *lock_5=0; } int r = rand()%10 + 1; double s = (double)r/100; sleep(s); } exit(0); } else { //cout << "Registered the sender " << pid << endl; senders[i] = pid; } } //cout << "End of registering the signal generators" << endl; ///////////////////////////////////////////////////////////////////////////////////////////////////// //////////////////////////End of registering the signal generators/////////////////////////////////// ///////////////////////////////////////////////////////////////////////////////////////////////////// //Either sleep for 30 seconds and terminate the program or if the number of signals generated reaches 10000, terminate the program if(option = 1) { sleep(90); terminate_processes(); } else { while(true) { if(total_signal_count >= MAX_SIGNAL_COUNT) { terminate_processes(); } else { sleep(0.001); } } } } void signal_catcher_1(int the_sig) { while(__sync_lock_test_and_set(lock_1,1) != 0) { } (*usrsig1_handler_count) = (*usrsig1_handler_count) + 1; cout << "Signal Handler 1 " << *usrsig1_handler_count << endl; __sync_lock_release(lock_1); } void signal_catcher_2(int the_sig) { while(__sync_lock_test_and_set(lock_2,1) != 0) { } (*usrsig2_handler_count) = (*usrsig2_handler_count) + 1; __sync_lock_release(lock_2); } void signal_catcher_main(int the_sig) { while(__sync_lock_test_and_set(lock_6,1) != 0) { } total_signal_count++; *lock_6 = 0; } void signal_catcher_int(int the_sig) { for(int i=0; i<NUM_SENDER_PROCESSES; i++) { kill(senders[i],SIGKILL); } for(int i=0; i<NUM_HANDLER_PROCESSES; i++) { kill(handlers[i],SIGKILL); } kill(reporter,SIGKILL); exit(3); } void signal_catcher_monitor(int the_sig) { cout << "Monitoring process " << *usrsig1_handler_count << endl; } Here is the initial segment of output Monitoring process 0 Monitoring process 0 Monitoring process 0 Monitoring process 0 Signal Handler 1 1 Monitoring process 2 Signal Handler 1 2 Signal Handler 1 3 Signal Handler 1 4 Monitoring process 4 Monitoring process Signal Handler 1 6 Signal Handler 1 7 Monitoring process 7 Monitoring process 8 Monitoring process 8 Signal Handler 1 9 Monitoring process 9 Monitoring process 9 Monitoring process 10 Signal Handler 1 11 Monitoring process 11 Monitoring process 12 Signal Handler 1 13 Signal Handler 1 14 Signal Handler 1 15 Signal Handler 1 16 Signal Handler 1 17 Signal Handler 1 18 Monitoring process 19 Signal Handler 1 20 Monitoring process 20 Signal Handler 1 21 Monitoring process 21 Monitoring process 21 Monitoring process 22 Monitoring process 22 Monitoring process 23 Signal Handler 1 24 Signal Handler 1 25 Monitoring process 25 Signal Handler 1 27 Signal Handler 1 28 Signal Handler 1 29 Here is the segment when the signal handler processes signal handlers are called in a burst Signal Handler 1 456 Signal Handler 1 457 Signal Handler 1 458 Signal Handler 1 459 Signal Handler 1 460 Signal Handler 1 461 Signal Handler 1 462 Signal Handler 1 463 Signal Handler 1 464 Signal Handler 1 465 Signal Handler 1 466 Signal Handler 1 467 Signal Handler 1 468 Signal Handler 1 469 Signal Handler 1 470 Signal Handler 1 471 Signal Handler 1 472 Signal Handler 1 473 Signal Handler 1 474 Signal Handler 1 475 Signal Handler 1 476 Signal Handler 1 477 Signal Handler 1 478 Signal Handler 1 479 Signal Handler 1 480 Signal Handler 1 481 Signal Handler 1 482 Signal Handler 1 483 Signal Handler 1 484 Signal Handler 1 485 Signal Handler 1 486 Signal Handler 1 487 Signal Handler 1 488 Signal Handler 1 489 Signal Handler 1 490 Signal Handler 1 491 Signal Handler 1 492 Signal Handler 1 493 Signal Handler 1 494 Signal Handler 1 495 Signal Handler 1 496 Signal Handler 1 497 Signal Handler 1 498 Signal Handler 1 499 Signal Handler 1 500 Signal Handler 1 501 Signal Handler 1 502 Signal Handler 1 503 Signal Handler 1 504 Signal Handler 1 505 Signal Handler 1 506 Here is the segment when the monitoring processes signal handlers are called in a burst Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Why isn't it uniform afterwards. Why are they called in a burst?

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• Fragment shaders on a texture

  - by Snowangelic

  Hello stack overflow. I am trying to add some post-processing capabilities to a program. The rendering is done using openGL. I just want to allow the program to load some home made fragment shader and use them on the video stream. I wrote a little piece of shader using "OpenGL Shader Builder" that just turns a texture in grayscale. The shaders works well in the shader builder but I can't make it work in the main program. The screens stays all black. Here is the setup : @implementation PluginGLView - (id) initWithCoder: (NSCoder *) coder { const GLubyte * strExt; if ((self = [super initWithCoder:coder]) == nil) return nil; glLock = [[NSLock alloc] init]; if (nil == glLock) { [self release]; return nil; } // Init pixel format attribs NSOpenGLPixelFormatAttribute attrs[] = { NSOpenGLPFAAccelerated, NSOpenGLPFANoRecovery, NSOpenGLPFADoubleBuffer, 0 }; // Get pixel format from OpenGL NSOpenGLPixelFormat* pixFmt = [[NSOpenGLPixelFormat alloc] initWithAttributes:attrs]; if (!pixFmt) { NSLog(@"No Accelerated OpenGL pixel format found\n"); NSOpenGLPixelFormatAttribute attrs2[] = { NSOpenGLPFANoRecovery, 0 }; // Get pixel format from OpenGL pixFmt = [[NSOpenGLPixelFormat alloc] initWithAttributes:attrs2]; if (!pixFmt) { NSLog(@"No OpenGL pixel format found!\n"); [self release]; return nil; } } [self setPixelFormat:[pixFmt autorelease]]; /* long swapInterval = 1 ; [[self openGLContext] setValues:&swapInterval forParameter:NSOpenGLCPSwapInterval]; */ [glLock lock]; [[self openGLContext] makeCurrentContext]; // Init object members strExt = glGetString (GL_EXTENSIONS); texture_range = gluCheckExtension ((const unsigned char *)"GL_APPLE_texture_range", strExt) ? GL_TRUE : GL_FALSE; texture_hint = GL_STORAGE_SHARED_APPLE ; client_storage = gluCheckExtension ((const unsigned char *)"GL_APPLE_client_storage", strExt) ? GL_TRUE : GL_FALSE; rect_texture = gluCheckExtension((const unsigned char *)"GL_EXT_texture_rectangle", strExt) ? GL_TRUE : GL_FALSE; // Setup some basic OpenGL stuff glPixelStorei(GL_UNPACK_ALIGNMENT, 1); glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE); glColor4f(1.0f, 1.0f, 1.0f, 1.0f); glClearColor(0.0f, 0.0f, 0.0f, 1.0f); glClear(GL_COLOR_BUFFER_BIT); // Loads the shaders shader=LoadShader(GL_FRAGMENT_SHADER,"/Users/alexandremathieu/fragment.fs"); program=glCreateProgram(); glAttachShader(program, shader); glLinkProgram(program); glUseProgram(program); [NSOpenGLContext clearCurrentContext]; [glLock unlock]; image_width = 1024; image_height = 512; image_depth = 16; image_type = GL_UNSIGNED_SHORT_1_5_5_5_REV; image_base = (GLubyte *) calloc(((IMAGE_COUNT * image_width * image_height) / 3) * 4, image_depth >> 3); if (image_base == nil) { [self release]; return nil; } // Create and load textures for the first time [self loadTextures:GL_TRUE]; // Init fps timer //gettimeofday(&cycle_time, NULL); drawBG = YES; // Call for a redisplay noDisplay = YES; PSXDisplay.Disabled = 1; [self setNeedsDisplay:true]; return self; } And here is the "render screen" function wich basically...renders the screen. - (void)renderScreen { int bufferIndex = whichImage; glBindTexture(GL_TEXTURE_RECTANGLE_EXT, bufferIndex+1); glUseProgram(program); int loc=glGetUniformLocation(program, "texture"); glUniform1i(loc,bufferIndex+1); glTexSubImage2D(GL_TEXTURE_RECTANGLE_EXT, 0, 0, 0, image_width, image_height, GL_BGRA, image_type, image[bufferIndex]); glBegin(GL_QUADS); glTexCoord2f(0.0f, 0.0f); glVertex2f(-1.0f, 1.0f); glTexCoord2f(0.0f, image_height); glVertex2f(-1.0f, -1.0f); glTexCoord2f(image_width, image_height); glVertex2f(1.0f, -1.0f); glTexCoord2f(image_width, 0.0f); glVertex2f(1.0f, 1.0f); glEnd(); [[self openGLContext] flushBuffer]; [NSOpenGLContext clearCurrentContext]; //[glLock unlock]; } and finally here's the shader. uniform sampler2DRect texture; void main() { vec4 color, texel; color = gl_Color; texel = texture2DRect(texture, gl_TexCoord[0].xy); color *= texel; // Begin Shader float gray=0.0; gray+=(color.r + color.g + color.b)/3.0; color=vec4(gray,gray,gray,color.a); // End Shader gl_FragColor = color; } The loading and using of shaders works since I am able to turn the screen all red with this shader void main(){ gl_FragColor=vec4(1.0,0.0,0.0,1.0); } If the shader contains a syntax error I get an error message from the LoadShader function etc. If I remove the use of the shader, everything works normally. I think the problem comes from the "passing the texture as a uniform parameter" thing. But these are my very firsts step with openGL and I cant be sure of anything. Don't hesitate to ask for more info. Thank you Stack O.

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• Of these 3 methods for reading linked lists from shared memory, why is the 3rd fastest?

  - by Joseph Garvin

  I have a 'server' program that updates many linked lists in shared memory in response to external events. I want client programs to notice an update on any of the lists as quickly as possible (lowest latency). The server marks a linked list's node's state_ as FILLED once its data is filled in and its next pointer has been set to a valid location. Until then, its state_ is NOT_FILLED_YET. I am using memory barriers to make sure that clients don't see the state_ as FILLED before the data within is actually ready (and it seems to work, I never see corrupt data). Also, state_ is volatile to be sure the compiler doesn't lift the client's checking of it out of loops. Keeping the server code exactly the same, I've come up with 3 different methods for the client to scan the linked lists for changes. The question is: Why is the 3rd method fastest? Method 1: Round robin over all the linked lists (called 'channels') continuously, looking to see if any nodes have changed to 'FILLED': void method_one() { std::vector<Data*> channel_cursors; for(ChannelList::iterator i = channel_list.begin(); i != channel_list.end(); ++i) { Data* current_item = static_cast<Data*>(i->get(segment)->tail_.get(segment)); channel_cursors.push_back(current_item); } while(true) { for(std::size_t i = 0; i < channel_list.size(); ++i) { Data* current_item = channel_cursors[i]; ACQUIRE_MEMORY_BARRIER; if(current_item->state_ == NOT_FILLED_YET) { continue; } log_latency(current_item->tv_sec_, current_item->tv_usec_); channel_cursors[i] = static_cast<Data*>(current_item->next_.get(segment)); } } } Method 1 gave very low latency when then number of channels was small. But when the number of channels grew (250K+) it became very slow because of looping over all the channels. So I tried... Method 2: Give each linked list an ID. Keep a separate 'update list' to the side. Every time one of the linked lists is updated, push its ID on to the update list. Now we just need to monitor the single update list, and check the IDs we get from it. void method_two() { std::vector<Data*> channel_cursors; for(ChannelList::iterator i = channel_list.begin(); i != channel_list.end(); ++i) { Data* current_item = static_cast<Data*>(i->get(segment)->tail_.get(segment)); channel_cursors.push_back(current_item); } UpdateID* update_cursor = static_cast<UpdateID*>(update_channel.tail_.get(segment)); while(true) { if(update_cursor->state_ == NOT_FILLED_YET) { continue; } ::uint32_t update_id = update_cursor->list_id_; Data* current_item = channel_cursors[update_id]; if(current_item->state_ == NOT_FILLED_YET) { std::cerr << "This should never print." << std::endl; // it doesn't continue; } log_latency(current_item->tv_sec_, current_item->tv_usec_); channel_cursors[update_id] = static_cast<Data*>(current_item->next_.get(segment)); update_cursor = static_cast<UpdateID*>(update_cursor->next_.get(segment)); } } Method 2 gave TERRIBLE latency. Whereas Method 1 might give under 10us latency, Method 2 would inexplicably often given 8ms latency! Using gettimeofday it appears that the change in update_cursor-state_ was very slow to propogate from the server's view to the client's (I'm on a multicore box, so I assume the delay is due to cache). So I tried a hybrid approach... Method 3: Keep the update list. But loop over all the channels continuously, and within each iteration check if the update list has updated. If it has, go with the number pushed onto it. If it hasn't, check the channel we've currently iterated to. void method_three() { std::vector<Data*> channel_cursors; for(ChannelList::iterator i = channel_list.begin(); i != channel_list.end(); ++i) { Data* current_item = static_cast<Data*>(i->get(segment)->tail_.get(segment)); channel_cursors.push_back(current_item); } UpdateID* update_cursor = static_cast<UpdateID*>(update_channel.tail_.get(segment)); while(true) { for(std::size_t i = 0; i < channel_list.size(); ++i) { std::size_t idx = i; ACQUIRE_MEMORY_BARRIER; if(update_cursor->state_ != NOT_FILLED_YET) { //std::cerr << "Found via update" << std::endl; i--; idx = update_cursor->list_id_; update_cursor = static_cast<UpdateID*>(update_cursor->next_.get(segment)); } Data* current_item = channel_cursors[idx]; ACQUIRE_MEMORY_BARRIER; if(current_item->state_ == NOT_FILLED_YET) { continue; } found_an_update = true; log_latency(current_item->tv_sec_, current_item->tv_usec_); channel_cursors[idx] = static_cast<Data*>(current_item->next_.get(segment)); } } } The latency of this method was as good as Method 1, but scaled to large numbers of channels. The problem is, I have no clue why. Just to throw a wrench in things: if I uncomment the 'found via update' part, it prints between EVERY LATENCY LOG MESSAGE. Which means things are only ever found on the update list! So I don't understand how this method can be faster than method 2. The full, compilable code (requires GCC and boost-1.41) that generates random strings as test data is at: http://pastebin.com/e3HuL0nr

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• FreeBSD performance tuning. Sysctls, loader.conf, kernel

  - by SaveTheRbtz

  I wanted to share knowledge of tuning FreeBSD via sysctl.conf/loader.conf/KENCONF. It was initially based on Igor Sysoev's (author of nginx) presentation about FreeBSD tuning up to 100,000-200,000 active connections. Tunings are for FreeBSD-CURRENT. Since 7.2 amd64 some of them are tuned well by default. Prior 7.0 some of them are boot only (set via /boot/loader.conf) or does not exist at all. sysctl.conf: # No zero mapping feature # May break wine # (There are also reports about broken samba3) #security.bsd.map_at_zero=0 # If you have really busy webserver with apache13 you may run out of processes #kern.maxproc=10000 # Same for servers with apache2 / Pound #kern.threads.max_threads_per_proc=4096 # Max. backlog size kern.ipc.somaxconn=4096 # Shared memory // 7.2+ can use shared memory > 2Gb kern.ipc.shmmax=2147483648 # Sockets kern.ipc.maxsockets=204800 # Can cause this on older kernels: # http://old.nabble.com/Significant-performance-regression-for-increased-maxsockbuf-on-8.0-RELEASE-tt26745981.html#a26745981 ) kern.ipc.maxsockbuf=10485760 # Mbuf 2k clusters (on amd64 7.2+ 25600 is default) # For such high value vm.kmem_size must be increased to 3G kern.ipc.nmbclusters=262144 # Jumbo pagesize(_SC_PAGESIZE) clusters # Used as general packet storage for jumbo frames # can be monitored via `netstat -m` #kern.ipc.nmbjumbop=262144 # Jumbo 9k/16k clusters # If you are using them #kern.ipc.nmbjumbo9=65536 #kern.ipc.nmbjumbo16=32768 # For lower latency you can decrease scheduler's maximum time slice # default: stathz/10 (~ 13) #kern.sched.slice=1 # Increase max command-line length showed in `ps` (e.g for Tomcat/Java) # Default is PAGE_SIZE / 16 or 256 on x86 # This avoids commands to be presented as [executable] in `ps` # For more info see: http://www.freebsd.org/cgi/query-pr.cgi?pr=120749 kern.ps_arg_cache_limit=4096 # Every socket is a file, so increase them kern.maxfiles=204800 kern.maxfilesperproc=200000 kern.maxvnodes=200000 # On some systems HPET is almost 2 times faster than default ACPI-fast # Useful on systems with lots of clock_gettime / gettimeofday calls # See http://old.nabble.com/ACPI-fast-default-timecounter,-but-HPET-83--faster-td23248172.html # After revision 222222 HPET became default: http://svnweb.freebsd.org/base?view=revision&revision=222222 kern.timecounter.hardware=HPET # Small receive space, only usable on http-server, on file server this # should be increased to 65535 or even more #net.inet.tcp.recvspace=8192 # This is useful on Fat-Long-Pipes #net.inet.tcp.recvbuf_max=10485760 #net.inet.tcp.recvbuf_inc=65535 # Small send space is useful for http servers that serve small files # Autotuned since 7.x net.inet.tcp.sendspace=16384 # This is useful on Fat-Long-Pipes #net.inet.tcp.sendbuf_max=10485760 #net.inet.tcp.sendbuf_inc=65535 # Turn off receive autotuning # You can play with it. #net.inet.tcp.recvbuf_auto=0 #net.inet.tcp.sendbuf_auto=0 # This should be enabled if you going to use big spaces (>64k) # Also timestamp field is useful when using syncookies net.inet.tcp.rfc1323=1 # Turn this off on high-speed, lossless connections (LAN 1Gbit+) # If you set it there is no need in TCP_NODELAY sockopt (see man tcp) net.inet.tcp.delayed_ack=0 # This feature is useful if you are serving data over modems, Gigabit Ethernet, # or even high speed WAN links (or any other link with a high bandwidth delay product), # especially if you are also using window scaling or have configured a large send window. # Automatically disables on small RTT ( http://www.freebsd.org/cgi/cvsweb.cgi/src/sys/netinet/tcp_subr.c?#rev1.237 ) # This sysctl was removed in 10-CURRENT: # See: http://www.mail-archive.com/[email protected]/msg06178.html #net.inet.tcp.inflight.enable=0 # TCP slowstart algorithm tunings # We assuming we have very fast clients #net.inet.tcp.slowstart_flightsize=100 #net.inet.tcp.local_slowstart_flightsize=100 # Disable randomizing of ports to avoid false RST # Before usage check SA here www.bsdcan.org/2006/papers/ImprovingTCPIP.pdf # (it's also says that port randomization auto-disables at some conn.rates, but I didn't checked it thou) #net.inet.ip.portrange.randomized=0 # Increase portrange # For outgoing connections only. Good for seed-boxes and ftp servers. net.inet.ip.portrange.first=1024 net.inet.ip.portrange.last=65535 # # stops route cache degregation during a high-bandwidth flood # http://www.freebsd.org/doc/en/books/handbook/securing-freebsd.html #net.inet.ip.rtexpire=2 net.inet.ip.rtminexpire=2 net.inet.ip.rtmaxcache=1024 # Security net.inet.ip.redirect=0 net.inet.ip.sourceroute=0 net.inet.ip.accept_sourceroute=0 net.inet.icmp.maskrepl=0 net.inet.icmp.log_redirect=0 net.inet.icmp.drop_redirect=1 net.inet.tcp.drop_synfin=1 # # There is also good example of sysctl.conf with comments: # http://www.thern.org/projects/sysctl.conf # # icmp may NOT rst, helpful for those pesky spoofed # icmp/udp floods that end up taking up your outgoing # bandwidth/ifqueue due to all that outgoing RST traffic. # #net.inet.tcp.icmp_may_rst=0 # Security net.inet.udp.blackhole=1 net.inet.tcp.blackhole=2 # IPv6 Security # For more info see http://www.fosslc.org/drupal/content/security-implications-ipv6 # Disable Node info replies # To see this vulnerability in action run `ping6 -a sglAac ::1` or `ping6 -w ::1` on unprotected node net.inet6.icmp6.nodeinfo=0 # Turn on IPv6 privacy extensions # For more info see proposal http://unix.derkeiler.com/Mailing-Lists/FreeBSD/net/2008-06/msg00103.html net.inet6.ip6.use_tempaddr=1 net.inet6.ip6.prefer_tempaddr=1 # Disable ICMP redirect net.inet6.icmp6.rediraccept=0 # Disable acceptation of RA and auto linklocal generation if you don't use them #net.inet6.ip6.accept_rtadv=0 #net.inet6.ip6.auto_linklocal=0 # Increases default TTL, sometimes useful # Default is 64 net.inet.ip.ttl=128 # Lessen max segment life to conserve resources # ACK waiting time in miliseconds # (default: 30000. RFC from 1979 recommends 120000) net.inet.tcp.msl=5000 # Max bumber of timewait sockets net.inet.tcp.maxtcptw=200000 # Don't use tw on local connections # As of 15 Apr 2009. Igor Sysoev says that nolocaltimewait has some buggy realization. # So disable it or now till get fixed #net.inet.tcp.nolocaltimewait=1 # FIN_WAIT_2 state fast recycle net.inet.tcp.fast_finwait2_recycle=1 # Time before tcp keepalive probe is sent # default is 2 hours (7200000) #net.inet.tcp.keepidle=60000 # Should be increased until net.inet.ip.intr_queue_drops is zero net.inet.ip.intr_queue_maxlen=4096 # Interrupt handling via multiple CPU, but with context switch. # You can play with it. Default is 1; #net.isr.direct=0 # This is for routers only #net.inet.ip.forwarding=1 #net.inet.ip.fastforwarding=1 # This speed ups dummynet when channel isn't saturated net.inet.ip.dummynet.io_fast=1 # Increase dummynet(4) hash #net.inet.ip.dummynet.hash_size=2048 #net.inet.ip.dummynet.max_chain_len # Should be increased when you have A LOT of files on server # (Increase until vfs.ufs.dirhash_mem becomes lower) vfs.ufs.dirhash_maxmem=67108864 # Note from commit http://svn.freebsd.org/base/head@211031 : # For systems with RAID volumes and/or virtualization envirnments, where # read performance is very important, increasing this sysctl tunable to 32 # or even more will demonstratively yield additional performance benefits. vfs.read_max=32 # Explicit Congestion Notification (see http://en.wikipedia.org/wiki/Explicit_Congestion_Notification) net.inet.tcp.ecn.enable=1 # Flowtable - flow caching mechanism # Useful for routers #net.inet.flowtable.enable=1 #net.inet.flowtable.nmbflows=65535 # Extreme polling tuning #kern.polling.burst_max=1000 #kern.polling.each_burst=1000 #kern.polling.reg_frac=100 #kern.polling.user_frac=1 #kern.polling.idle_poll=0 # IPFW dynamic rules and timeouts tuning # Increase dyn_buckets till net.inet.ip.fw.curr_dyn_buckets is lower net.inet.ip.fw.dyn_buckets=65536 net.inet.ip.fw.dyn_max=65536 net.inet.ip.fw.dyn_ack_lifetime=120 net.inet.ip.fw.dyn_syn_lifetime=10 net.inet.ip.fw.dyn_fin_lifetime=2 net.inet.ip.fw.dyn_short_lifetime=10 # Make packets pass firewall only once when using dummynet # i.e. packets going thru pipe are passing out from firewall with accept #net.inet.ip.fw.one_pass=1 # shm_use_phys Wires all shared pages, making them unswappable # Use this to lessen Virtual Memory Manager's work when using Shared Mem. # Useful for databases #kern.ipc.shm_use_phys=1 # ZFS # Enable prefetch. Useful for sequential load type i.e fileserver. # FreeBSD sets vfs.zfs.prefetch_disable to 1 on any i386 systems and # on any amd64 systems with less than 4GB of avaiable memory # For additional info check this nabble thread http://old.nabble.com/Samba-read-speed-performance-tuning-td27964534.html #vfs.zfs.prefetch_disable=0 # On highload servers you may notice following message in dmesg: # "Approaching the limit on PV entries, consider increasing either the # vm.pmap.shpgperproc or the vm.pmap.pv_entry_max tunable" vm.pmap.shpgperproc=2048 loader.conf: # Accept filters for data, http and DNS requests # Useful when your software uses select() instead of kevent/kqueue or when you under DDoS # DNS accf available on 8.0+ accf_data_load="YES" accf_http_load="YES" accf_dns_load="YES" # Async IO system calls aio_load="YES" # Linux specific devices in /dev # As for 8.1 it only /dev/full #lindev_load="YES" # Adds NCQ support in FreeBSD # WARNING! all ad[0-9]+ devices will be renamed to ada[0-9]+ # 8.0+ only #ahci_load="YES" #siis_load="YES" # FreeBSD 8.2+ # New Congestion Control for FreeBSD # http://caia.swin.edu.au/urp/newtcp/tools/cc_chd-readme-0.1.txt # http://www.ietf.org/proceedings/78/slides/iccrg-5.pdf # Initial merge commit message http://www.mail-archive.com/[email protected]/msg31410.html #cc_chd_load="YES" # Increase kernel memory size to 3G. # # Use ONLY if you have KVA_PAGES in kernel configuration, and you have more than 3G RAM # Otherwise panic will happen on next reboot! # # It's required for high buffer sizes: kern.ipc.nmbjumbop, kern.ipc.nmbclusters, etc # Useful on highload stateful firewalls, proxies or ZFS fileservers # (FreeBSD 7.2+ amd64 users: Check that current value is lower!) #vm.kmem_size="3G" # If your server has lots of swap (>4Gb) you should increase following value # according to http://lists.freebsd.org/pipermail/freebsd-hackers/2009-October/029616.html # Otherwise you'll be getting errors # "kernel: swap zone exhausted, increase kern.maxswzone" # kern.maxswzone="256M" # Older versions of FreeBSD can't tune maxfiles on the fly #kern.maxfiles="200000" # Useful for databases # Sets maximum data size to 1G # (FreeBSD 7.2+ amd64 users: Check that current value is lower!) #kern.maxdsiz="1G" # Maximum buffer size(vfs.maxbufspace) # You can check current one via vfs.bufspace # Should be lowered/upped depending on server's load-type # Usually decreased to preserve kmem # (default is 10% of mem) #kern.maxbcache="512M" # Sendfile buffers # For i386 only #kern.ipc.nsfbufs=10240 # FreeBSD 9+ # HPET "legacy route" support. It should allow HPET to work per-CPU # See http://www.mail-archive.com/[email protected]/msg03603.html #hint.atrtc.0.clock=0 #hint.attimer.0.clock=0 #hint.hpet.0.legacy_route=1 # syncache Hash table tuning net.inet.tcp.syncache.hashsize=1024 net.inet.tcp.syncache.bucketlimit=512 net.inet.tcp.syncache.cachelimit=65536 # Increased hostcache # Later host cache can be viewed via net.inet.tcp.hostcache.list hidden sysctl # Very useful for it's RTT RTTVAR # Must be power of two net.inet.tcp.hostcache.hashsize=65536 # hashsize * bucketlimit (which is 30 by default) # It allocates 255Mb (1966080*136) of RAM net.inet.tcp.hostcache.cachelimit=1966080 # TCP control-block Hash table tuning net.inet.tcp.tcbhashsize=4096 # Disable ipfw deny all # Should be uncommented when there is a chance that # kernel and ipfw binary may be out-of sync on next reboot #net.inet.ip.fw.default_to_accept=1 # # SIFTR (Statistical Information For TCP Research) is a kernel module that # logs a range of statistics on active TCP connections to a log file. # See prerelease notes http://groups.google.com/group/mailing.freebsd.current/browse_thread/thread/b4c18be6cdce76e4 # and man 4 sitfr #siftr_load="YES" # Enable superpages, for 7.2+ only # Also read http://lists.freebsd.org/pipermail/freebsd-hackers/2009-November/030094.html vm.pmap.pg_ps_enabled=1 # Usefull if you are using Intel-Gigabit NIC #hw.em.rxd=4096 #hw.em.txd=4096 #hw.em.rx_process_limit="-1" # Also if you have ALOT interrupts on NIC - play with following parameters # NOTE: You should set them for every NIC #dev.em.0.rx_int_delay: 250 #dev.em.0.tx_int_delay: 250 #dev.em.0.rx_abs_int_delay: 250 #dev.em.0.tx_abs_int_delay: 250 # There is also multithreaded version of em/igb drivers can be found here: # http://people.yandex-team.ru/~wawa/ # # for additional em monitoring and statistics use # sysctl dev.em.0.stats=1 ; dmesg # sysctl dev.em.0.debug=1 ; dmesg # Also after r209242 (-CURRENT) there is a separate sysctl for each stat variable; # Same tunings for igb #hw.igb.rxd=4096 #hw.igb.txd=4096 #hw.igb.rx_process_limit=100 # Some useful netisr tunables. See sysctl net.isr #net.isr.maxthreads=4 #net.isr.defaultqlimit=4096 #net.isr.maxqlimit: 10240 # Bind netisr threads to CPUs #net.isr.bindthreads=1 # # FreeBSD 9.x+ # Increase interface send queue length # See commit message http://svn.freebsd.org/viewvc/base?view=revision&revision=207554 #net.link.ifqmaxlen=1024 # Nicer boot logo =) loader_logo="beastie" And finally here is KERNCONF: # Just some of them, see also # cat /sys/{i386,amd64,}/conf/NOTES # This one useful only on i386 #options KVA_PAGES=512 # You can play with HZ in environments with high interrupt rate (default is 1000) # 100 is for my notebook to prolong it's battery life #options HZ=100 # Polling is goot on network loads with high packet rates and low-end NICs # NB! Do not enable it if you want more than one netisr thread #options DEVICE_POLLING # Eliminate datacopy on socket read-write # To take advantage with zero copy sockets you should have an MTU >= 4k # This req. is only for receiving data. # Read more in man zero_copy_sockets # Also this epic thread on kernel trap: # http://kerneltrap.org/node/6506 # Here Linus says that "anybody that does it that way (FreeBSD) is totally incompetent" #options ZERO_COPY_SOCKETS # Support TCP sign. Used for IPSec options TCP_SIGNATURE # There was stackoverflow found in KAME IPSec stack: # See http://secunia.com/advisories/43995/ # For quick workaround you can use `ipfw add deny proto ipcomp` options IPSEC # This ones can be loaded as modules. They described in loader.conf section #options ACCEPT_FILTER_DATA #options ACCEPT_FILTER_HTTP # Adding ipfw, also can be loaded as modules options IPFIREWALL # On 8.1+ you can disable verbose to see blocked packets on ipfw0 interface. # Also there is no point in compiling verbose into the kernel, because # now there is net.inet.ip.fw.verbose tunable. #options IPFIREWALL_VERBOSE #options IPFIREWALL_VERBOSE_LIMIT=10 options IPFIREWALL_FORWARD # Adding kernel NAT options IPFIREWALL_NAT options LIBALIAS # Traffic shaping options DUMMYNET # Divert, i.e. for userspace NAT options IPDIVERT # This is for OpenBSD's pf firewall device pf device pflog # pf's QoS - ALTQ options ALTQ options ALTQ_CBQ # Class Bases Queuing (CBQ) options ALTQ_RED # Random Early Detection (RED) options ALTQ_RIO # RED In/Out options ALTQ_HFSC # Hierarchical Packet Scheduler (HFSC) options ALTQ_PRIQ # Priority Queuing (PRIQ) options ALTQ_NOPCC # Required for SMP build # Pretty console # Manual can be found here http://forums.freebsd.org/showthread.php?t=6134 #options VESA #options SC_PIXEL_MODE # Disable reboot on Ctrl Alt Del #options SC_DISABLE_REBOOT # Change normal|kernel messages color options SC_NORM_ATTR=(FG_GREEN|BG_BLACK) options SC_KERNEL_CONS_ATTR=(FG_YELLOW|BG_BLACK) # More scroll space options SC_HISTORY_SIZE=8192 # Adding hardware crypto device device crypto device cryptodev # Useful network interfaces device vlan device tap #Virtual Ethernet driver device gre #IP over IP tunneling device if_bridge #Bridge interface device pfsync #synchronization interface for PF device carp #Common Address Redundancy Protocol device enc #IPsec interface device lagg #Link aggregation interface device stf #IPv4-IPv6 port # Also for my notebook, but may be used with Opteron device amdtemp # Same for Intel processors device coretemp # man 4 cpuctl device cpuctl # CPU control pseudo-device # Support for ECMP. More than one route for destination # Works even with default route so one can use it as LB for two ISP # For now code is unstable and panics (panic: rtfree 2) on route deletions. #options RADIX_MPATH # Multicast routing #options MROUTING #options PIM # Debug & DTrace options KDB # Kernel debugger related code options KDB_TRACE # Print a stack trace for a panic options KDTRACE_FRAME # amd64-only(?) options KDTRACE_HOOKS # all architectures - enable general DTrace hooks #options DDB #options DDB_CTF # all architectures - kernel ELF linker loads CTF data # Adaptive spining in lockmgr (8.x+) # See http://www.mail-archive.com/[email protected]/msg10782.html options ADAPTIVE_LOCKMGRS # UTF-8 in console (8.x+) #options TEKEN_UTF8 # FreeBSD 8.1+ # Deadlock resolver thread # For additional information see http://www.mail-archive.com/[email protected]/msg18124.html # (FYI: "resolution" is panic so use with caution) #options DEADLKRES # Increase maximum size of Raw I/O and sendfile(2) readahead #options MAXPHYS=(1024*1024) #options MAXBSIZE=(1024*1024) # For scheduler debug enable following option. # Debug will be available via `kern.sched.stats` sysctl # For more information see http://svnweb.freebsd.org/base/head/sys/conf/NOTES?view=markup #options SCHED_STATS If you are tuning network for maximum performance you may wish to play with ifconfig options like: # You can list all capabilities via `ifconfig -m` ifconfig [-]rxcsum [-]txcsum [-]tso [-]lro mtu In case you've enabled DDB in kernel config, you should edit your /etc/ddb.conf and add something like this to enable automatic reboot (and textdump as bonus): script kdb.enter.panic=textdump set; capture on; show pcpu; bt; ps; alltrace; capture off; call doadump; reset script kdb.enter.default=textdump set; capture on; bt; ps; capture off; call doadump; reset And do not forget to add ddb_enable="YES" to /etc/rc.conf Since FreeBSD 9 you can select to enable/disable flowcontrol on your NIC: # See http://en.wikipedia.org/wiki/Ethernet_flow_control and # http://www.mail-archive.com/[email protected]/msg07927.html for additional info ifconfig bge0 media auto mediaopt flowcontrol PS. Also most of FreeBSD's limits can be monitored by # vmstat -z and # limits PPS. variety of network counters can be monitored via # netstat -s In FreeBSD-9 netstat's -Q option appeared, try following command to display netisr stats # netstat -Q PPPS. also see # man 7 tuning PPPPS. I wanted to thank FreeBSD community, especially author of nginx - Igor Sysoev, nginx-ru@ and FreeBSD-performance@ mailing lists for providing useful information about FreeBSD tuning. FreeBSD WIP * Whats cooking for FreeBSD 7? * Whats cooking for FreeBSD 8? * Whats cooking for FreeBSD 9? So here is the question: What tunings are you using on yours FreeBSD servers? You can also post your /etc/sysctl.conf, /boot/loader.conf, kernel options, etc with description of its' meaning (do not copy-paste from sysctl -d). Don't forget to specify server type (web, smb, gateway, etc) Let's share experience!

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• ubuntu: sem_timedwait not waking (C)

  - by gillez

  I have 3 processes which need to be synchronized. Process one does something then wakes process two and sleeps, which does something then wakes process three and sleeps, which does something and wakes process one and sleeps. The whole loop is timed to run around 25hz (caused by an external sync into process one before it triggers process two in my "real" application). I use sem_post to trigger (wake) each process, and sem_timedwait() to wait for the trigger. This all works successfully for several hours. However at some random time (usually after somewhere between two and four hours), one of the processes starts timing out in sem_timedwait(), even though I am sure the semaphore is being triggered with sem_post(). To prove this I even use sem_getvalue() immediately after the timeout, and the value is 1, so the timedwait should have been triggered. Please see following code: #include <stdio.h> #include <time.h> #include <string.h> #include <errno.h> #include <semaphore.h> sem_t trigger_sem1, trigger_sem2, trigger_sem3; // The main thread process. Called three times with a different num arg - 1, 2 or 3. void *thread(void *arg) { int num = (int) arg; sem_t *wait, *trigger; int val, retval; struct timespec ts; struct timeval tv; switch (num) { case 1: wait = &trigger_sem1; trigger = &trigger_sem2; break; case 2: wait = &trigger_sem2; trigger = &trigger_sem3; break; case 3: wait = &trigger_sem3; trigger = &trigger_sem1; break; } while (1) { // The first thread delays by 40ms to time the whole loop. // This is an external sync in the real app. if (num == 1) usleep(40000); // print sem value before we wait. If this is 1, sem_timedwait() will // return immediately, otherwise it will block until sem_post() is called on this sem. sem_getvalue(wait, &val); printf("sem%d wait sync sem%d. val before %d\n", num, num, val); // get current time and add half a second for timeout. gettimeofday(&tv, NULL); ts.tv_sec = tv.tv_sec; ts.tv_nsec = (tv.tv_usec + 500000); // add half a second if (ts.tv_nsec > 1000000) { ts.tv_sec++; ts.tv_nsec -= 1000000; } ts.tv_nsec *= 1000; /* convert to nanosecs */ retval = sem_timedwait(wait, &ts); if (retval == -1) { // timed out. Print value of sem now. This should be 0, otherwise sem_timedwait // would have woken before timeout (unless the sem_post happened between the // timeout and this call to sem_getvalue). sem_getvalue(wait, &val); printf("!!!!!! sem%d sem_timedwait failed: %s, val now %d\n", num, strerror(errno), val); } else printf("sem%d wakeup.\n", num); // get value of semaphore to trigger. If it's 1, don't post as it has already been // triggered and sem_timedwait on this sem *should* not block. sem_getvalue(trigger, &val); if (val <= 0) { printf("sem%d send sync sem%d. val before %d\n", num, (num == 3 ? 1 : num+1), val); sem_post(trigger); } else printf("!! sem%d not sending sync, val %d\n", num, val); } } int main(int argc, char *argv[]) { pthread_t t1, t2, t3; // create semaphores. val of sem1 is 1 to trigger straight away and start the whole ball rolling. if (sem_init(&trigger_sem1, 0, 1) == -1) perror("Error creating trigger_listman semaphore"); if (sem_init(&trigger_sem2, 0, 0) == -1) perror("Error creating trigger_comms semaphore"); if (sem_init(&trigger_sem3, 0, 0) == -1) perror("Error creating trigger_vws semaphore"); pthread_create(&t1, NULL, thread, (void *) 1); pthread_create(&t2, NULL, thread, (void *) 2); pthread_create(&t3, NULL, thread, (void *) 3); pthread_join(t1, NULL); pthread_join(t2, NULL); pthread_join(t3, NULL); } The following output is printed when the program is running correctly (at the start and for a random but long time after). The value of sem1 is always 1 before thread1 waits as it sleeps for 40ms, by which time sem3 has triggered it, so it wakes straight away. The other two threads wait until the semaphore is received from the previous thread. [...] sem1 wait sync sem1. val before 1 sem1 wakeup. sem1 send sync sem2. val before 0 sem2 wakeup. sem2 send sync sem3. val before 0 sem2 wait sync sem2. val before 0 sem3 wakeup. sem3 send sync sem1. val before 0 sem3 wait sync sem3. val before 0 sem1 wait sync sem1. val before 1 sem1 wakeup. sem1 send sync sem2. val before 0 [...] However, after a few hours, one of the threads begins to timeout. I can see from the output that the semaphore is being triggered, and when I print the value after the timeout is is 1. So sem_timedwait should have woken up well before the timeout. I would never expect the value of the semaphore to be 1 after the timeout, save for the very rare occasion (almost certainly never but it's possible) when the trigger happens after the timeout but before I call sem_getvalue. Also, once it begins to fail, every sem_timedwait() on that semaphore also fails in the same way. See the following output, which I've line-numbered: 01 sem3 wait sync sem3. val before 0 02 sem1 wakeup. 03 sem1 send sync sem2. val before 0 04 sem2 wakeup. 05 sem2 send sync sem3. val before 0 06 sem2 wait sync sem2. val before 0 07 sem1 wait sync sem1. val before 0 08 !!!!!! sem3 sem_timedwait failed: Connection timed out, val now 1 09 sem3 send sync sem1. val before 0 10 sem3 wait sync sem3. val before 1 11 sem3 wakeup. 12 !! sem3 not sending sync, val 1 13 sem3 wait sync sem3. val before 0 14 sem1 wakeup. [...] On line 1, thread 3 (which I have confusingly called sem1 in the printf) waits for sem3 to be triggered. On line 5, sem2 calls sem_post for sem3. However, line 8 shows sem3 timing out, but the value of the semaphore is 1. thread3 then triggers sem1 and waits again (10). However, because the value is already 1, it wakes straight away. It doesn't send sem1 again as this has all happened before control is given to thread1, however it then waits again (val is now 0) and sem1 wakes up. This now repeats for ever, sem3 always timing out and showing that the value is 1. So, my question is why does sem3 timeout, even though the semaphore has been triggered and the value is clearly 1? I would never expect to see line 08 in the output. If it times out (because, say thread 2 has crashed or is taking too long), the value should be 0. And why does it work fine for 3 or 4 hours first before getting into this state? This is using Ubuntu 9.4 with kernel 2.6.28. The same procedure has been working properly on Redhat and Fedora. But I'm now trying to port to ubuntu! Thanks for any advice, Giles

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