Search Results

Search found 16324 results on 653 pages for 'per thread'.

Page 86/653 | < Previous Page | 82 83 84 85 86 87 88 89 90 91 92 93  | Next Page >

• Can I set a breakpoint in Visual Studio (c++) to break on a thread context switch?

  - by Tim

  We want to only break in a certain thread. Any idea how to do that? I can't seem to find a way to break on that condition.

  Read the article

• Backing up my Windows Home Server to the Cloud&hellip;

  - by eddraper

  Ok, here’s my scenario: Windows Home Server with a little over 3TB of storage.  This includes many years of our home network’s PC backups, music, videos, etcetera. I’d like to get a backup off-site, and the existing APIs and apps such as CloudBerry Labs WHS Backup service are making it easy.  Now, all it’s down to is vendor and the cost of the actual storage.   So,  I thought I’d take a lazy Saturday morning and do some research on this and get the ball rolling.  What I discovered stunned me…   First off, the pricing for just about everything was loaded with complexity.  I learned that it wasn’t just about storage… it was about network usage, requests, sites, replication, and on and on. I really don’t see this as rocket science.  I have a disk image.  I want to put it in the cloud.  I’m not going to be be using it but once daily for incremental backups.  Sounds like a common scenario.  Yes, if “things get real” and my server goes down, I will need to bring down a lot of data and utilize a fair amount of vendor infrastructure.  However, this may never happen.  Offsite storage is an insurance policy.   The complexity of the cost structures, perhaps by design, create an environment where it’s incredibly hard to model bottom line costs and compare vendor all-up pricing.  As it is a “lazy Saturday morning,” I’m not in the mood for such antics and I decide to shirk the endeavor entirely.  Thus, I decided to simply fire up calc.exe and do some a simple arithmetic model based on price per GB.  I shuddered at the results.  Certainly something was wrong… did I misplace a decimal point?  Then I discovered CloudBerry’s own calculator.   Nope, I hadn’t misplaced those decimals after all.  Check it out (pricing based on 3174 GB):   Amazon S3 $398.00 per month $4761 per year Azure $396.75 per month $4761 per year Google $380.88 per month $4570.56 per year   Conclusion: Rampant crack smoking at vendors.  Seriously.  Out. Of. Their. Minds. Now, to Amazon’s credit, vision, and outright common sense, they had one offering which directly addresses my scenario:   Amazon Glacier $31.74 per month $380.88 per year   hmmm… It’s on the table.  Let’s see what it would cost to just buy some drives, an enclosure and cart them over to a friend’s house.   2 x 2TB Drives from NewEgg.com $199.99   Enclosure $39.99     $239.98   Carting data to back and forth to friend’s within walking distance pain   Leave drive unplugged at friend’s $0 for electricity   Possible data loss No way I can come and go every day.     I think I’ll think on this a bit more…

  Read the article

• SQL 2012 Licensing Thoughts

  - by Geoff N. Hiten

  The only thing more controversial than new Federal Tax plans is new Licensing plans from Microsoft.  In both cases, everyone calculates several numbers.  First, will I pay more or less under this plan?  Second, will my competition pay more or less than now?  Third, will <insert interesting person/company here> pay more or less?  Not that items 2 and 3 are meaningful, that is just how people think. Much like tax plans, the devil is in the details, so lets see how this looks.  Microsoft shows it here: http://www.microsoft.com/sqlserver/en/us/future-editions/sql2012-licensing.aspx First up is a switch from per-socket to per-core licensing.  Anyone who didn’t see something like this coming should rapidly search for a new line of work because you are not paying attention.  The explosion of multi-core processors has made SQL Server a bargain.  Microsoft is in business to make money and the old per-socket model was not going to do that going forward. Per-core licensing also simplifies virtualization licensing.  Physical Core = Virtual Core, at least for licensing.  Oversubscribe your processors, that’s your lookout.  You still pay for  what is exposed to the VM.  The cool part is you can seamlessly move physical and virtual workloads around and the licenses follow.  The catch is you have to have Software Assurance to make the licenses mobile.  Nice touch there. Let’s have a moment of silence for the late, unlamented, largely ignored Workgroup Edition.  To quote the Microsoft  FAQ:  “Standard becomes our sole edition for basic database needs”.  Considering I haven’t encountered a singe instance of SQL Server Workgroup Edition in the wild, I don’t think this will be all that controversial. As for pricing, it looks like a wash with current per-socket pricing based on four core sockets.  Interestingly, that is the minimum core count Microsoft proposes to swap to transition per-socket to per-core if you are on Software Assurance.  Reading the fine print shows that if you are using more, you will get more core licenses: From the licensing FAQ. 15. How do I migrate from processor licenses to core licenses?  What is the migration path? Licenses purchased with Software Assurance (SA) will upgrade to SQL Server 2012 at no additional cost. EA/EAP customers can continue buying processor licenses until your next renewal after June 30, 2012. At that time, processor licenses will be exchanged for core-based licenses sufficient to cover the cores in use by processor-licensed databases (minimum of 4 cores per processor for Standard and Enterprise, and minimum of 8 EE cores per processor for Datacenter). Looks like the folks who invested in the AMD 12-core chips will make out like bandits. Now, on to something new: SQL Server Business Intelligence Edition. Yep, finally a BI-specific SKU licensed for server+CAL configurations only.  Note that Enterprise Edition still supports the complete feature set; the BI Edition is intended for smaller shops who want to use the full BI feature set but without needing Enterprise Edition scale (or costs).  No, you don’t get ColumnStore, Compression, or Partitioning in the BI Edition.  Those are Enterprise scale features, ThankYouVeryMuch.  Then again, your starting licensing costs are about one sixth of an Enterprise Edition system (based on an 8 core server). The only part of the message I am missing is if the current Failover Licensing Policy will change.  Do we need to fully or partially license failover servers?  That is a detail I definitely want to know.

  Read the article

• Multithreading 2D gravity calculations

  - by Postman

  I'm building a space exploration game and I've currently started working on gravity ( In C# with XNA). The gravity still needs tweaking, but before I can do that, I need to address some performance issues with my physics calculations. This is using 100 objects, normally rendering 1000 of them with no physics calculations gets well over 300 FPS (which is my FPS cap), but any more than 10 or so objects brings the game (and the single thread it runs on) to its knees when doing physics calculations. I checked my thread usage and the first thread was killing itself from all the work, so I figured I just needed to do the physics calculation on another thread. However when I try to run the Gravity.cs class's Update method on another thread, even if Gravity's Update method has nothing in it, the game is still down to 2 FPS. Gravity.cs public void Update() { foreach (KeyValuePair<string, Entity> e in entityEngine.Entities) { Vector2 Force = new Vector2(); foreach (KeyValuePair<string, Entity> e2 in entityEngine.Entities) { if (e2.Key != e.Key) { float distance = Vector2.Distance(entityEngine.Entities[e.Key].Position, entityEngine.Entities[e2.Key].Position); if (distance > (entityEngine.Entities[e.Key].Texture.Width / 2 + entityEngine.Entities[e2.Key].Texture.Width / 2)) { double angle = Math.Atan2(entityEngine.Entities[e2.Key].Position.Y - entityEngine.Entities[e.Key].Position.Y, entityEngine.Entities[e2.Key].Position.X - entityEngine.Entities[e.Key].Position.X); float mult = 0.1f * (entityEngine.Entities[e.Key].Mass * entityEngine.Entities[e2.Key].Mass) / distance * distance; Vector2 VecForce = new Vector2((float)Math.Cos(angle), (float)Math.Sin(angle)); VecForce.Normalize(); Force = Vector2.Add(Force, VecForce * mult); } } } entityEngine.Entities[e.Key].Position += Force; } } Yeah, I know. It's a nested foreach loop, but I don't know how else to do the gravity calculation, and this seems to work, it's just so intensive that it needs its own thread. (Even if someone knows a super efficient way to do these calculations, I'd still like to know how I COULD do it on multiple threads instead) EntityEngine.cs (manages an instance of Gravity.cs) public class EntityEngine { public Dictionary<string, Entity> Entities = new Dictionary<string, Entity>(); public Gravity gravity; private Thread T; public EntityEngine() { gravity = new Gravity(this); } public void Update() { foreach (KeyValuePair<string, Entity> e in Entities) { Entities[e.Key].Update(); } T = new Thread(new ThreadStart(gravity.Update)); T.IsBackground = true; T.Start(); } } EntityEngine is created in Game1.cs, and its Update() method is called within Game1.cs. I need my physics calculation in Gravity.cs to run every time the game updates, in a separate thread so that the calculation doesn't slow the game down to horribly low (0-2) FPS. How would I go about making this threading work? (any suggestions for an improved Planetary Gravity system are welcome if anyone has them) I'm also not looking for a lesson in why I shouldn't use threading or the dangers of using it incorrectly, I'm looking for a straight answer on how to do it. I've already spent an hour googling this very question with little results that I understood or were helpful. I don't mean to come off rude, but it always seems hard as a programming noob to get a straight meaningful answer, I usually rather get an answer so complex I'd easily be able to solve my issue if I understood it, or someone saying why I shouldn't do what I want to do and offering no alternatives (that are helpful). Thank you for the help!

  Read the article

• High Resolution Timeouts

  - by user12607257

  The default resolution of application timers and timeouts is now 1 msec in Solaris 11.1, down from 10 msec in previous releases. This improves out-of-the-box performance of polling and event based applications, such as ticker applications, and even the Oracle rdbms log writer. More on that in a moment. As a simple example, the poll() system call takes a timeout argument in units of msec: System Calls poll(2) NAME poll - input/output multiplexing SYNOPSIS int poll(struct pollfd fds[], nfds_t nfds, int timeout); In Solaris 11, a call to poll(NULL,0,1) returns in 10 msec, because even though a 1 msec interval is requested, the implementation rounds to the system clock resolution of 10 msec. In Solaris 11.1, this call returns in 1 msec. In specification lawyer terms, the resolution of CLOCK_REALTIME, introduced by POSIX.1b real time extensions, is now 1 msec. The function clock_getres(CLOCK_REALTIME,&res) returns 1 msec, and any library calls whose man page explicitly mention CLOCK_REALTIME, such as nanosleep(), are subject to the new resolution. Additionally, many legacy functions that pre-date POSIX.1b and do not explicitly mention a clock domain, such as poll(), are subject to the new resolution. Here is a fairly comprehensive list: nanosleep pthread_mutex_timedlock pthread_mutex_reltimedlock_np pthread_rwlock_timedrdlock pthread_rwlock_reltimedrdlock_np pthread_rwlock_timedwrlock pthread_rwlock_reltimedwrlock_np mq_timedreceive mq_reltimedreceive_np mq_timedsend mq_reltimedsend_np sem_timedwait sem_reltimedwait_np poll select pselect _lwp_cond_timedwait _lwp_cond_reltimedwait semtimedop sigtimedwait aiowait aio_waitn aio_suspend port_get port_getn cond_timedwait cond_reltimedwait setitimer (ITIMER_REAL) misc rpc calls, misc ldap calls This change in resolution was made feasible because we made the implementation of timeouts more efficient a few years back when we re-architected the callout subsystem of Solaris. Previously, timeouts were tested and expired by the kernel's clock thread which ran 100 times per second, yielding a resolution of 10 msec. This did not scale, as timeouts could be posted by every CPU, but were expired by only a single thread. The resolution could be changed by setting hires_tick=1 in /etc/system, but this caused the clock thread to run at 1000 Hz, which made the potential scalability problem worse. Given enough CPUs posting enough timeouts, the clock thread could be a performance bottleneck. We fixed that by re-implementing the timeout as a per-CPU timer interrupt (using the cyclic subsystem, for those familiar with Solaris internals). This decoupled the clock thread frequency from timeout resolution, and allowed us to improve default timeout resolution without adding CPU overhead in the clock thread. Here are some exceptions for which the default resolution is still 10 msec. The thread scheduler's time quantum is 10 msec by default, because preemption is driven by the clock thread (plus helper threads for scalability). See for example dispadmin, priocntl, fx_dptbl, rt_dptbl, and ts_dptbl. This may be changed using hires_tick. The resolution of the clock_t data type, primarily used in DDI functions, is 10 msec. It may be changed using hires_tick. These functions are only used by developers writing kernel modules. A few functions that pre-date POSIX CLOCK_REALTIME mention _SC_CLK_TCK, CLK_TCK, "system clock", or no clock domain. These functions are still driven by the clock thread, and their resolution is 10 msec. They include alarm, pcsample, times, clock, and setitimer for ITIMER_VIRTUAL and ITIMER_PROF. Their resolution may be changed using hires_tick. Now back to the database. How does this help the Oracle log writer? Foreground processes post a redo record to the log writer, which releases them after the redo has committed. When a large number of foregrounds are waiting, the release step can slow down the log writer, so under heavy load, the foregrounds switch to a mode where they poll for completion. This scales better because every foreground can poll independently, but at the cost of waiting the minimum polling interval. That was 10 msec, but is now 1 msec in Solaris 11.1, so the foregrounds process transactions faster under load. Pretty cool.

  Read the article

• What is my miniport's service name?

  - by Ian Boyd

  i am trying to query the physical sector size of my drive using fsutil: C:\Windows\system32>fsutil fsinfo ntfsinfo c: NTFS Volume Serial Number : 0x78cc11b2cc116c1e Version : 3.1 Number Sectors : 0x000000003a382fff Total Clusters : 0x00000000074705ff Free Clusters : 0x00000000022fc29b Total Reserved : 0x00000000000007d0 Bytes Per Sector : 512 Bytes Per Physical Sector : <Not Supported> Bytes Per Cluster : 4096 Bytes Per FileRecord Segment : 1024 Clusters Per FileRecord Segment : 0 Mft Valid Data Length : 0x00000000305c0000 Mft Start Lcn : 0x00000000000c0000 Mft2 Start Lcn : 0x0000000003a382ff Mft Zone Start : 0x0000000006951940 Mft Zone End : 0x0000000006951c80 RM Identifier: 19B22CBE-570D-19DE-9C72-CD758F800DDC You can see that the Bytes Per Physical Sector value is Not Supported: Bytes Per Physical Sector : <Not Supported> In KB Article Microsoft support policy for 4K sector hard drives in Windows, Microsoft says: If fsutil.exe continues to display "Bytes Per Physical Sector : " after you apply the latest storage driver and the required hotfixes, make sure that the following registry path exists: HKLM\CurrentControlSet\Services\<miniport’s service name>\Parameters\Device\ Name: EnableQueryAccessAlignment Type: REG_DWORD Value: 1: Enable The only thing i don't know is what my Miniport's service name is. What is my miniport's service name. i know that my SATA drives are in AHCI mode, and AHCI uses the msahci driver service: Is that my miniport service? "MSAHCI"? See also Hitachi - Advanced Format Technology Brief RMPrepUSB - Advanced Format (4K sector) hard disks Microsoft support policy for 4K sector hard drives in Windows OSR Online - Advance Disk Format support in Storport Virtual Mniport diver Default cluster size for NTFS, FAT, and exFAT Wikipedia - Advanced Format

  Read the article

• "Unable to initialize module" fileinfo php-pecl-Fileinfo.x86_64

  - by Myers Network

  I have a brand new server server that I am trying to get setup up. This is a 64 bit machine that I can not install "fileinfo" or "memcache". I have uninstalled these and reinstalled them using yum and pecl with no luck. Yum install fine "no error" but then get error when running php. pecl from what I can tell is only installing 32bit. Does not put anything in the lib64 directory. Here is my output from php -v: PHP Warning: PHP Startup: fileinfo: Unable to initialize module Module compiled with module API=20050922, debug=0, thread-safety=0 PHP compiled with module API=20060613, debug=0, thread-safety=0 These options need to match in Unknown on line 0 PHP Warning: PHP Startup: memcache: Unable to initialize module Module compiled with module API=20050922, debug=0, thread-safety=0 PHP compiled with module API=20060613, debug=0, thread-safety=0 These options need to match in Unknown on line 0 PHP 5.2.14 (cli) (built: Aug 12 2010 16:03:48) Copyright (c) 1997-2010 The PHP Group Zend Engine v2.2.0, Copyright (c) 1998-2010 Zend Technologies Here is some other system info incase you need it uname: Linux server.actham.us 2.6.18-194.26.1.el5 #1 SMP Tue Nov 9 12:54:20 EST 2010 x86_64 x86_64 x86_64 GNU/Linux php -m: PHP Warning: PHP Startup: fileinfo: Unable to initialize module Module compiled with module API=20050922, debug=0, thread-safety=0 PHP compiled with module API=20060613, debug=0, thread-safety=0 These options need to match in Unknown on line 0 PHP Warning: PHP Startup: memcache: Unable to initialize module Module compiled with module API=20050922, debug=0, thread-safety=0 PHP compiled with module API=20060613, debug=0, thread-safety=0 These options need to match in Unknown on line 0 [PHP Modules] bz2 calendar ctype curl date dbase dom exif filter ftp gd gettext gmp hash iconv imap json ldap libxml mbstring mcrypt mysql mysqli openssl pcntl pcre PDO pdo_mysql pdo_sqlite readline Reflection session shmop SimpleXML sockets SPL standard tokenizer wddx xml xmlreader xmlrpc xmlwriter xsl zip zlib [Zend Modules] Any help would be greatly appreciated, thanks....

  Read the article

• "Unable to initialize module" fileinfo php-pecl-Fileinfo.x86_64

  - by Myers Network

  I have a brand new server server that I am trying to get setup up. This is a 64 bit machine that I can not install "fileinfo" or "memcache". I have uninstalled these and reinstalled them using yum and pecl with no luck. Yum install fine "no error" but then get error when running php. pecl from what I can tell is only installing 32bit. Does not put anything in the lib64 directory. Here is my output from php -v: PHP Warning: PHP Startup: fileinfo: Unable to initialize module Module compiled with module API=20050922, debug=0, thread-safety=0 PHP compiled with module API=20060613, debug=0, thread-safety=0 These options need to match in Unknown on line 0 PHP Warning: PHP Startup: memcache: Unable to initialize module Module compiled with module API=20050922, debug=0, thread-safety=0 PHP compiled with module API=20060613, debug=0, thread-safety=0 These options need to match in Unknown on line 0 PHP 5.2.14 (cli) (built: Aug 12 2010 16:03:48) Copyright (c) 1997-2010 The PHP Group Zend Engine v2.2.0, Copyright (c) 1998-2010 Zend Technologies Here is some other system info incase you need it uname: Linux server.actham.us 2.6.18-194.26.1.el5 #1 SMP Tue Nov 9 12:54:20 EST 2010 x86_64 x86_64 x86_64 GNU/Linux php -m: PHP Warning: PHP Startup: fileinfo: Unable to initialize module Module compiled with module API=20050922, debug=0, thread-safety=0 PHP compiled with module API=20060613, debug=0, thread-safety=0 These options need to match in Unknown on line 0 PHP Warning: PHP Startup: memcache: Unable to initialize module Module compiled with module API=20050922, debug=0, thread-safety=0 PHP compiled with module API=20060613, debug=0, thread-safety=0 These options need to match in Unknown on line 0 [PHP Modules] bz2 calendar ctype curl date dbase dom exif filter ftp gd gettext gmp hash iconv imap json ldap libxml mbstring mcrypt mysql mysqli openssl pcntl pcre PDO pdo_mysql pdo_sqlite readline Reflection session shmop SimpleXML sockets SPL standard tokenizer wddx xml xmlreader xmlrpc xmlwriter xsl zip zlib [Zend Modules] Any help would be greatly appreciated, thanks....

  Read the article

• Windows 8.1 will not sleep after wake up

  - by per

  I have problem with sleep/screen saver on my new Windows 8.1 machine. It will go to to sleep or start screen saver after start (or restart). But if it goes to sleep (manually or automatically) and I wake it up, it wont start sleep or start screen saver again automatically. I updated chipset and graphic cards drivers. I don't have any homegroup. Does anyone have similar issue? Thanks for any advice, per

  Read the article

• Context migration in CUDA.NET

  - by Vyacheslav

  I'm currently using CUDA.NET library by GASS. I need to initialize cuda arrays (actually cublas vectors, but it doesn't matters) in one CPU thread and use them in other CPU thread. But CUDA context which holding all initialized arrays and loaded functions, can be attached to only one CPU thread. There is mechanism called context migration API to detach context from one thread and attach it to another. But i don't how to properly use it in CUDA.NET. I tried something like this: class Program { private static float[] vector1, vector2; private static CUDA cuda; private static CUBLAS cublas; private static CUdeviceptr ptr; static void Main(string[] args) { cuda = new CUDA(false); cublas = new CUBLAS(cuda); cuda.Init(); cuda.CreateContext(0); AllocateVectors(); cuda.DetachContext(); CUcontext context = cuda.PopCurrentContext(); GetVectorFromDeviceAsync(context); } private static void AllocateVectors() { vector1 = new float[]{1f, 2f, 3f, 4f, 5f}; ptr = cublas.Allocate(vector1.Length, sizeof (float)); cublas.SetVector(vector1, ptr); vector2 = new float[5]; } private static void GetVectorFromDevice(object objContext) { CUcontext localContext = (CUcontext) objContext; cuda.PushCurrentContext(localContext); cuda.AttachContext(localContext); //change vector somehow vector1[0] = -1; //copy changed vector to device cublas.SetVector(vector1, ptr); cublas.GetVector(ptr, vector2); CUDADriver.cuCtxPopCurrent(ref localContext); } private static void GetVectorFromDeviceAsync(CUcontext cUcontext) { Thread thread = new Thread(GetVectorFromDevice); thread.IsBackground = false; thread.Start(cUcontext); } } But execution fails on attempt to copy changed vector to device because context is not attached? Any ideas how i can get it work?

  Read the article

• getting SIGSEGV in std::_List_const_iterator<Exiv2::Exifdatum>::operator++ whilst using jni

  - by HJED

  Hi I'm using jni to access the exiv2 API in my Java project and I'm getting a SIGSEGV error in std::_List_const_iterator::operator++. I'm uncertain how to fix this error. I've tried using high -Xmx values as well as running on both jdk1.6.0 (server and cacao JVMs) and 1.7.0 (server JVM). gdb traceback: #0 0x00007fffa36f2363 in std::_List_const_iterator<Exiv2::Exifdatum>::operator++ (this=0x7ffff7fd3500) at /usr/include/c++/4.4/bits/stl_list.h:223 #1 0x00007fffa36f2310 in std::__distance<std::_List_const_iterator<Exiv2::Exifdatum> > (__first=..., __last=...) at /usr/include/c++/4.4/bits/stl_iterator_base_funcs.h:79 #2 0x00007fffa36f224d in std::distance<std::_List_const_iterator<Exiv2::Exifdatum> > (__first=..., __last=...) at /usr/include/c++/4.4/bits/stl_iterator_base_funcs.h:114 #3 0x00007fffa36f1f27 in std::list<Exiv2::Exifdatum, std::allocator<Exiv2::Exifdatum> >::size (this=0x7fffa4030910) at /usr/include/c++/4.4/bits/stl_list.h:805 #4 0x00007fffa36f1d50 in Exiv2::ExifData::count (this=0x7fffa4030910) at /usr/local/include/exiv2/exif.hpp:518 #5 0x00007fffa36f1d30 in Exiv2::ExifData::empty (this=0x7fffa4030910) at /usr/local/include/exiv2/exif.hpp:516 #6 0x00007fffa36f1763 in getVars (path=0x7fffa401d2f0 "/home/hjed/PC100001.JPG", env=0x6131c8, obj=0x7ffff7fd37a8) at src/main.cpp:146 #7 0x00007fffa36f19d8 in Java_photo_exiv2_Exiv2MetaDataStore_impl_1loadFromExiv (env=0x6131c8, obj=0x7ffff7fd37a8, path=0x7ffff7fd37a0, obj2=0x7ffff7fd3798) at src/main.cpp:160 #8 0x00007ffff21d9cc8 in ?? () #9 0x00000000fffffffe in ?? () #10 0x00007ffff7fd3740 in ?? () #11 0x0000000000613000 in ?? () #12 0x00007ffff7fd3738 in ?? () #13 0x00007fffaa1076e0 in ?? () #14 0x00007ffff7fd37a8 in ?? () #15 0x00007fffaa108d10 in ?? () #16 0x0000000000000000 in ?? () Java error: # A fatal error has been detected by the Java Runtime Environment: # # SIGSEGV (0xb) at pc=0x00007fac11223363, pid=11905, tid=140378349111040 # # JRE version: 6.0_20-b20 # Java VM: OpenJDK 64-Bit Server VM (19.0-b09 mixed mode linux-amd64 ) # Derivative: IcedTea6 1.9.2 # Distribution: Ubuntu 10.10, package 6b20-1.9.2-0ubuntu2 # Problematic frame: # C [libExiff2-binding.so+0x4363] _ZNSt20_List_const_iteratorIN5Exiv29ExifdatumEEppEv+0xf # # If you would like to submit a bug report, please include # instructions how to reproduce the bug and visit: # https://bugs.launchpad.net/ubuntu/+source/openjdk-6/ # The crash happened outside the Java Virtual Machine in native code. # See problematic frame for where to report the bug. # --------------- T H R E A D --------------- Current thread (0x0000000000dbf000): JavaThread "main" [_thread_in_native, id=11909, stack(0x00007fac61920000,0x00007fac61a21000)] siginfo:si_signo=SIGSEGV: si_errno=0, si_code=128 (), si_addr=0x0000000000000000 Registers: ... Register to memory mapping: RAX=0x6c8948f0245c8948 0x6c8948f0245c8948 is pointing to unknown location RBX=0x00007fac0c042c00 0x00007fac0c042c00 is pointing to unknown location RCX=0x0000000000000000 0x0000000000000000 is pointing to unknown location RDX=0x6c8948f0245c8948 0x6c8948f0245c8948 is pointing to unknown location RSP=0x00007fac61a1f4e0 0x00007fac61a1f4e0 is pointing into the stack for thread: 0x0000000000dbf000 "main" prio=10 tid=0x0000000000dbf000 nid=0x2e85 runnable [0x00007fac61a1f000] java.lang.Thread.State: RUNNABLE RBP=0x00007fac61a1f4e0 0x00007fac61a1f4e0 is pointing into the stack for thread: 0x0000000000dbf000 "main" prio=10 tid=0x0000000000dbf000 nid=0x2e85 runnable [0x00007fac61a1f000] java.lang.Thread.State: RUNNABLE RSI=0x00007fac61a1f4f0 0x00007fac61a1f4f0 is pointing into the stack for thread: 0x0000000000dbf000 "main" prio=10 tid=0x0000000000dbf000 nid=0x2e85 runnable [0x00007fac61a1f000] java.lang.Thread.State: RUNNABLE RDI=0x00007fac61a1f500 0x00007fac61a1f500 is pointing into the stack for thread: 0x0000000000dbf000 "main" prio=10 tid=0x0000000000dbf000 nid=0x2e85 runnable [0x00007fac61a1f000] java.lang.Thread.State: RUNNABLE R8 =0x00007fac0c054630 0x00007fac0c054630 is pointing to unknown location R9 =0x00007fac61a1f358 0x00007fac61a1f358 is pointing into the stack for thread: 0x0000000000dbf000 "main" prio=10 tid=0x0000000000dbf000 nid=0x2e85 runnable [0x00007fac61a1f000] java.lang.Thread.State: RUNNABLE R10=0x00007fac61a1f270 0x00007fac61a1f270 is pointing into the stack for thread: 0x0000000000dbf000 "main" prio=10 tid=0x0000000000dbf000 nid=0x2e85 runnable [0x00007fac61a1f000] java.lang.Thread.State: RUNNABLE R11=0x00007fac11223354 0x00007fac11223354: _ZNSt20_List_const_iteratorIN5Exiv29ExifdatumEEppEv+0 in /home/hjed/libExiff2-binding.so at 0x00007fac1121f000 R12=0x0000000000dbf000 "main" prio=10 tid=0x0000000000dbf000 nid=0x2e85 runnable [0x00007fac61a1f000] java.lang.Thread.State: RUNNABLE R13=0x00007fac13ad1be8 {method} - klass: {other class} R14=0x00007fac61a1f7a8 0x00007fac61a1f7a8 is pointing into the stack for thread: 0x0000000000dbf000 "main" prio=10 tid=0x0000000000dbf000 nid=0x2e85 runnable [0x00007fac61a1f000] java.lang.Thread.State: RUNNABLE R15=0x0000000000dbf000 "main" prio=10 tid=0x0000000000dbf000 nid=0x2e85 runnable [0x00007fac61a1f000] java.lang.Thread.State: RUNNABLE Top of Stack: (sp=0x00007fac61a1f4e0) ... Instructions: (pc=0x00007fac11223363) ... Stack: [0x00007fac61920000,0x00007fac61a21000], sp=0x00007fac61a1f4e0, free space=1021k Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code) C [libExiff2-binding.so+0x4363] _ZNSt20_List_const_iteratorIN5Exiv29ExifdatumEEppEv+0xf C [libExiff2-binding.so+0x4310] _ZSt10__distanceISt20_List_const_iteratorIN5Exiv29ExifdatumEEENSt15iterator_traitsIT_E15difference_typeES5_S5_St18input_iterator_tag+0x26 C [libExiff2-binding.so+0x424d] _ZSt8distanceISt20_List_const_iteratorIN5Exiv29ExifdatumEEENSt15iterator_traitsIT_E15difference_typeES5_S5_+0x36 C [libExiff2-binding.so+0x3f27] _ZNKSt4listIN5Exiv29ExifdatumESaIS1_EE4sizeEv+0x33 C [libExiff2-binding.so+0x3d50] _ZNK5Exiv28ExifData5countEv+0x18 C [libExiff2-binding.so+0x3d30] _ZNK5Exiv28ExifData5emptyEv+0x18 C [libExiff2-binding.so+0x3763] _Z7getVarsPKcP7JNIEnv_P8_jobject+0x3e3 C [libExiff2-binding.so+0x39d8] Java_photo_exiv2_Exiv2MetaDataStore_impl_1loadFromExiv+0x4b j photo.exiv2.Exiv2MetaDataStore.impl_loadFromExiv(Ljava/lang/String;Lphoto/exiv2/Exiv2MetaDataStore;)V+0 j photo.exiv2.Exiv2MetaDataStore.loadFromExiv2()V+9 j photo.exiv2.Exiv2MetaDataStore.loadData()V+1 j photo.exiv2.Exiv2MetaDataStore.<init>(Lphoto/ImageFile;)V+10 j photo.ImageFile.<init>(Ljava/lang/String;)V+11 j test.Main.main([Ljava/lang/String;)V+67 v ~StubRoutines::call_stub V [libjvm.so+0x428698] V [libjvm.so+0x4275c8] V [libjvm.so+0x432943] V [libjvm.so+0x447f91] C [java+0x3495] JavaMain+0xd75 Java frames: (J=compiled Java code, j=interpreted, Vv=VM code) j photo.exiv2.Exiv2MetaDataStore.impl_loadFromExiv(Ljava/lang/String;Lphoto/exiv2/Exiv2MetaDataStore;)V+0 j photo.exiv2.Exiv2MetaDataStore.loadFromExiv2()V+9 j photo.exiv2.Exiv2MetaDataStore.loadData()V+1 j photo.exiv2.Exiv2MetaDataStore.<init>(Lphoto/ImageFile;)V+10 j photo.ImageFile.<init>(Ljava/lang/String;)V+11 j test.Main.main([Ljava/lang/String;)V+67 v ~StubRoutines::call_stub --------------- P R O C E S S --------------- Java Threads: ( => current thread ) 0x00007fac0c028000 JavaThread "Low Memory Detector" daemon [_thread_blocked, id=11924, stack(0x00007fac11532000,0x00007fac11633000)] 0x00007fac0c025800 JavaThread "CompilerThread1" daemon [_thread_blocked, id=11923, stack(0x00007fac11633000,0x00007fac11734000)] 0x00007fac0c022000 JavaThread "CompilerThread0" daemon [_thread_blocked, id=11922, stack(0x00007fac11734000,0x00007fac11835000)] 0x00007fac0c01f800 JavaThread "Signal Dispatcher" daemon [_thread_blocked, id=11921, stack(0x00007fac11835000,0x00007fac11936000)] 0x00007fac0c001000 JavaThread "Finalizer" daemon [_thread_blocked, id=11920, stack(0x00007fac11e2d000,0x00007fac11f2e000)] 0x0000000000e36000 JavaThread "Reference Handler" daemon [_thread_blocked, id=11919, stack(0x00007fac11f2e000,0x00007fac1202f000)] =>0x0000000000dbf000 JavaThread "main" [_thread_in_native, id=11909, stack(0x00007fac61920000,0x00007fac61a21000)] Other Threads: 0x0000000000e2f800 VMThread [stack: 0x00007fac1202f000,0x00007fac12130000] [id=11918] 0x00007fac0c02b000 WatcherThread [stack: 0x00007fac11431000,0x00007fac11532000] [id=11925] ... Heap PSYoungGen total 18432K, used 632K [0x00007fac47210000, 0x00007fac486a0000, 0x00007fac5bc10000) eden space 15808K, 4% used [0x00007fac47210000,0x00007fac472ae188,0x00007fac48180000) from space 2624K, 0% used [0x00007fac48410000,0x00007fac48410000,0x00007fac486a0000) to space 2624K, 0% used [0x00007fac48180000,0x00007fac48180000,0x00007fac48410000) PSOldGen total 42240K, used 0K [0x00007fac1de10000, 0x00007fac20750000, 0x00007fac47210000) object space 42240K, 0% used [0x00007fac1de10000,0x00007fac1de10000,0x00007fac20750000) PSPermGen total 21248K, used 2831K [0x00007fac13810000, 0x00007fac14cd0000, 0x00007fac1de10000) object space 21248K, 13% used [0x00007fac13810000,0x00007fac13ad3d80,0x00007fac14cd0000) Dynamic libraries: ... VM Arguments: jvm_args: -Dfile.encoding=UTF-8 java_command: test.Main Launcher Type: SUN_STANDARD Environment Variables: PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games USERNAME=hjed LD_LIBRARY_PATH=/usr/lib/jvm/java-6-openjdk/jre/lib/amd64/server:/usr/lib/jvm/java-6-openjdk/jre/lib/amd64:/usr/lib/jvm/java-6-openjdk/jre/../lib/amd64 SHELL=/bin/bash DISPLAY=:0.0 Signal Handlers: ... --------------- S Y S T E M --------------- OS:Ubuntu 10.10 (maverick) uname:Linux 2.6.35-24-generic #42-Ubuntu SMP Thu Dec 2 02:41:37 UTC 2010 x86_64 libc:glibc 2.12.1 NPTL 2.12.1 rlimit: STACK 8192k, CORE 0k, NPROC infinity, NOFILE 1024, AS infinity load average:0.27 0.31 0.30 /proc/meminfo: MemTotal: 4048200 kB MemFree: 106552 kB Buffers: 838212 kB Cached: 1172496 kB SwapCached: 0 kB Active: 1801316 kB Inactive: 1774880 kB Active(anon): 1224708 kB Inactive(anon): 355012 kB Active(file): 576608 kB Inactive(file): 1419868 kB Unevictable: 64 kB Mlocked: 64 kB SwapTotal: 7065596 kB SwapFree: 7065596 kB Dirty: 20 kB Writeback: 0 kB AnonPages: 1565608 kB Mapped: 213424 kB Shmem: 14216 kB Slab: 164812 kB SReclaimable: 102576 kB SUnreclaim: 62236 kB KernelStack: 4784 kB PageTables: 44908 kB NFS_Unstable: 0 kB Bounce: 0 kB WritebackTmp: 0 kB CommitLimit: 9089696 kB Committed_AS: 3676872 kB VmallocTotal: 34359738367 kB VmallocUsed: 332952 kB VmallocChunk: 34359397884 kB HardwareCorrupted: 0 kB HugePages_Total: 0 HugePages_Free: 0 HugePages_Rsvd: 0 HugePages_Surp: 0 Hugepagesize: 2048 kB DirectMap4k: 48704 kB DirectMap2M: 4136960 kB CPU:total 8 (4 cores per cpu, 2 threads per core) family 6 model 26 stepping 5, cmov, cx8, fxsr, mmx, sse, sse2, sse3, ssse3, sse4.1, sse4.2, popcnt, ht Memory: 4k page, physical 4048200k(106552k free), swap 7065596k(7065596k free) vm_info: OpenJDK 64-Bit Server VM (19.0-b09) for linux-amd64 JRE (1.6.0_20-b20), built on Dec 10 2010 19:45:55 by "buildd" with gcc 4.4.5 main.cpp: jobject toJava(std::auto_ptr<Exiv2::Value> v, const char * type, JNIEnv * env) { jclass stringClass; jmethodID cid; jobject result; stringClass = env->FindClass("photo/exiv2/Value"); cid = env->GetMethodID(stringClass, "<init>", "(Ljava/lang/String;Ljava/lang/Object;)V"); jvalue val; if ((strcmp(type, "String") == 0) || (strcmp(type, "String") == 0)) { val.l = env->NewStringUTF(v->toString().c_str()); } else if (strcmp(type, "Short") == 0) { val.s = v->toLong(0); } else if (strcmp(type, "Long") == 0) { val.j = v->toLong(0); } result = env->NewObject(stringClass, cid, env->NewStringUTF(v->toString().c_str()), val); return result; } void inLoop(std::auto_ptr<MetadataContainer> md, JNIEnv * env, jmethodID mid, jobject obj) { jvalue values[2]; const char* key = md->key().c_str(); values[0].l = env->NewStringUTF(key); /** md->value().toString().c_str(); const char* value = md->typeName(); values[1].l = env->NewStringUTF(value); TODO: do type conversions */ //std::cout << md->typeName() << std::endl; /** const char* type = md->value().toString().c_str(); values[1].l = env->NewStringUTF(type);*/ values[1].l = toJava(md->getValue(), md->typeName(), env); env->CallVoidMethodA(obj, mid, values); } void getVars(const char* path, JNIEnv * env, jobject obj) { //Load image Exiv2::Image::AutoPtr image = Exiv2::ImageFactory::open(path); assert(image.get() != 0); image->readMetadata(); //load method jclass cls = env->GetObjectClass(obj); jmethodID mid = env->GetMethodID(cls, "exiv2_reciveElement", "(Ljava/lang/String;Lphoto/exiv2/Value;)V"); //Load IPTC data /**loadIPTC(image, path, env, obj, mid); loadEXIF(image, path, env, obj, mid);*/ Exiv2::IptcData &iptcData = image->iptcData(); if (mid != NULL) { //is there any IPTC data AND check that method exists if (iptcData.empty()) { std::string error(path); error += ": failed loading IPTC data, there may not be any data"; } else { Exiv2::IptcData::iterator end = iptcData.end(); for (Exiv2::IptcData::iterator md = iptcData.begin(); md != end; ++md) { std::auto_ptr<MetadataContainer> meta(new MetadataContainer(md)); inLoop(meta, env, mid, obj); } } Exiv2::ExifData &exifData = image->exifData(); //is there any Exif data AND check that method exists if (exifData.empty()) { //error occurs here (main.cpp:146) std::string error(path); error += ": failed loading Exif data, there may not be any data"; } else { Exiv2::ExifData::iterator end = exifData.end(); for (Exiv2::ExifData::iterator md = exifData.begin(); md != end; ++md) { std::auto_ptr<MetadataContainer> meta(new MetadataContainer(md)); inLoop(meta, env, mid, obj); } } } else { std::string error(path); error += ": failed to load method"; } } JNIEXPORT void JNICALL Java_photo_exiv2_Exiv2MetaDataStore_impl_1loadFromExiv(JNIEnv * env, jobject obj, jstring path, jobject obj2) { const char* path2 = env->GetStringUTFChars(path, NULL); getVars(path2, env, obj); env->ReleaseStringUTFChars(path, path2); } Thanks for any help, HJED EDIT This is the output when runing the jvm with the -cacao option: run: null:/usr/local/lib Error: Directory Olympus2 with 1536 entries considered invalid; not read. LOG: [0x00007ff005376700] We received a SIGSEGV and tried to handle it, but we were LOG: [0x00007ff005376700] unable to find a Java method at: LOG: [0x00007ff005376700] LOG: [0x00007ff005376700] PC=0x00007feffe4ee67d LOG: [0x00007ff005376700] LOG: [0x00007ff005376700] Dumping the current stacktrace: at photo.exiv2.Exiv2MetaDataStore.impl_loadFromExiv(Ljava/lang/String;Lphoto/exiv2/Exiv2MetaDataStore;)V(Native Method) at photo.exiv2.Exiv2MetaDataStore.loadFromExiv2()V(Exiv2MetaDataStore.java:38) at photo.exiv2.Exiv2MetaDataStore.loadData()V(Exiv2MetaDataStore.java:29) at photo.exiv2.MetaDataStore.<init>(Lphoto/ImageFile;)V(MetaDataStore.java:33) at photo.exiv2.Exiv2MetaDataStore.<init>(Lphoto/ImageFile;)V(Exiv2MetaDataStore.java:20) at photo.ImageFile.<init>(Ljava/lang/String;)V(ImageFile.java:22) at test.Main.main([Ljava/lang/String;)V(Main.java:28) LOG: [0x00007ff005376700] vm_abort: WARNING, port me to C++ and use os::abort() instead. LOG: [0x00007ff005376700] Exiting... LOG: [0x00007ff005376700] Backtrace (15 stack frames): LOG: [0x00007ff005376700] /usr/lib/jvm/java-6-openjdk/jre/lib/amd64/cacao/libjvm.so(+0x4ff54) [0x7ff004306f54] LOG: [0x00007ff005376700] /usr/lib/jvm/java-6-openjdk/jre/lib/amd64/cacao/libjvm.so(+0x5ac01) [0x7ff004311c01] LOG: [0x00007ff005376700] /usr/lib/jvm/java-6-openjdk/jre/lib/amd64/cacao/libjvm.so(+0x66e9a) [0x7ff00431de9a] LOG: [0x00007ff005376700] /usr/lib/jvm/java-6-openjdk/jre/lib/amd64/cacao/libjvm.so(+0x76408) [0x7ff00432d408] LOG: [0x00007ff005376700] /usr/lib/jvm/java-6-openjdk/jre/lib/amd64/cacao/libjvm.so(+0x79a4c) [0x7ff004330a4c] LOG: [0x00007ff005376700] /lib/libpthread.so.0(+0xfb40) [0x7ff004d53b40] LOG: [0x00007ff005376700] /home/hjed/libExiff2-binding.so(_ZNSt20_List_const_iteratorIN5Exiv29ExifdatumEEppEv+0xf) [0x7feffe4ee67d] LOG: [0x00007ff005376700] /home/hjed/libExiff2-binding.so(_ZSt10__distanceISt20_List_const_iteratorIN5Exiv29ExifdatumEEENSt15iterator_traitsIT_E15difference_typeES5_S5_St18input_iterator_tag+0x26) [0x7feffe4ee62a] LOG: [0x00007ff005376700] /home/hjed/libExiff2-binding.so(_ZSt8distanceISt20_List_const_iteratorIN5Exiv29ExifdatumEEENSt15iterator_traitsIT_E15difference_typeES5_S5_+0x36) [0x7feffe4ee567] LOG: [0x00007ff005376700] /home/hjed/libExiff2-binding.so(_ZNKSt4listIN5Exiv29ExifdatumESaIS1_EE4sizeEv+0x33) [0x7feffe4ee22b] LOG: [0x00007ff005376700] /home/hjed/libExiff2-binding.so(_ZNK5Exiv28ExifData5countEv+0x18) [0x7feffe4ee054] LOG: [0x00007ff005376700] /home/hjed/libExiff2-binding.so(_ZNK5Exiv28ExifData5emptyEv+0x18) [0x7feffe4ee034] LOG: [0x00007ff005376700] /home/hjed/libExiff2-binding.so(_Z7getVarsPKcP7JNIEnv_P8_jobject+0x3d7) [0x7feffe4ed947] LOG: [0x00007ff005376700] /home/hjed/libExiff2-binding.so(Java_photo_exiv2_Exiv2MetaDataStore_impl_1loadFromExiv+0x4b) [0x7feffe4edcdc] LOG: [0x00007ff005376700] [0x7feffe701ccd] Java Result: 134 BUILD SUCCESSFUL (total time: 0 seconds)

  Read the article

• Qt Socket blocking functions required to run in QThread where created. Any way past this?

  - by Alexander Kondratskiy

  The title is very cryptic, so here goes! I am writing a client that behaves in a very synchronous manner. Due to the design of the protocol and the server, everything has to happen sequentially (send request, wait for reply, service reply etc.), so I am using blocking sockets. Here is where Qt comes in. In my application I have a GUI thread, a command processing thread and a scripting engine thread. I create the QTcpSocket in the command processing thread, as part of my Client class. The Client class has various methods that boil down to writing to the socket, reading back a specific number of bytes, and returning a result. The problem comes when I try to directly call Client methods from the scripting engine thread. The Qt sockets randomly time out and when using a debug build of Qt, I get these warnings: QSocketNotifier: socket notifiers cannot be enabled from another thread QSocketNotifier: socket notifiers cannot be disabled from another thread Anytime I call these methods from the command processing thread (where Client was created), I do not get these problems. To simply phrase the situation: Calling blocking functions of QAbstractSocket, like waitForReadyRead(), from a thread other than the one where the socket was created (dynamically allocated), causes random behaviour and debug asserts/warnings. Anyone else experienced this? Ways around it? Thanks in advance.

  Read the article

• Handling user interface in a multi-threaded application (or being forced to have a UI-only main thre

  - by Patrick

  In my application, I have a 'logging' window, which shows all the logging, warnings, errors of the application. Last year my application was still single-threaded so this worked [quite] good. Now I am introducing multithreading. I quickly noticed that it's not a good idea to update the logging window from different threads. Reading some articles on keeping the UI in the main thread, I made a communication buffer, in which the other threads are adding their logging messages, and from which the main thread takes the messages and shows them in the logging window (this is done in the message loop). Now, in a part of my application, the memory usage increases dramatically, because the separate threads are generating lots of logging messages, and the main thread cannot empty the communication buffer quickly enough. After the while the memory decreases again (if the other threads have finished their work and the main thread gradually empties the communication buffer). I solved this problem by having a maximum size on the communication buffer, but then I run into a problem in the following situation: the main thread has to perform a complex action the main thread takes some parts of the action and let's separate threads execute this while the seperate threads are executing their logic, the main thread processes the results from the other threads and continues with its work if the other threads are finished Problem is that in this situation, if the other threads perform logging, there is no UI-message loop, and so the communication buffer is filled, but not emptied. I see two solutions in solving this problem: require the main thread to do regular polling of the communication buffer only performing user interface logic in the main thread (no other logic) I think the second solution seems the best, but this may not that easy to introduce in a big application (in my case it performs mathematical simulations). Are there any other solutions or tips? Or is one of the two proposed the best, easiest, most-pragmatic solution? Thanks, Patrick

  Read the article

• first major web app

  - by vbNewbie

  I have created a web app version of my previous crawler app and the initial form has controls to allow the client to make selections and start a search 'job'. These searches 'jobs' will be run my different threads created individually and added to a list to keep track of. Now the idea is to have another web form that will display this list of 'jobs' and their current status and will allow the jobs to be cancelled or removed only from the server side. This second form contains a grid to display these jobs. Now I have no idea if I should create the threads in the initial form code or send all user input to my main class which runs the search and if so how do I pass the the thread list to the second form to have it displayed on the grid. Any ideas really appreciated. Dim count As Integer = 0 Dim numThread As Integer = 0 Dim jobStartTime As Date Dim thread = New Thread(AddressOf ResetFormControlValues) 'StartBlogDiscovery) jobStartTime = Date.Now thread.Name = "Job" & jobStartTime 'clientName Session("Job") = "Job" & jobStartTime 'clientName thread.start() thread.sleep(50000) If numThread >= 10 Then For Each thread In threadlist thread.Join() Next Else numThread = numThread + 1 SyncLock threadlist threadlist.Enqueue(thread) End SyncLock End If this is the code that is called when the user clicks the search button on the inital form. this is what I just thought might work on the second web form if i used the session method. Try If Not Page.IsPostBack Then If Not Session("Job") = Nothing Then Grid1.DataSource = Session("Job") Grid1.DataBind() End If End If Finally

  Read the article

• How do I pause main() until all other threads have died?

  - by thechiman

  In my program, I am creating several threads in the main() method. The last line in the main method is a call to System.out.println(), which I don't want to call until all the threads have died. I have tried calling Thread.join() on each thread however that blocks each thread so that they execute sequentially instead of in parallel. Is there a way to block the main() thread until all other threads have finished executing? Here is the relevant part of my code: public static void main(String[] args) { //some other initialization code //Make array of Thread objects Thread[] racecars = new Thread[numberOfRaceCars]; //Fill array with RaceCar objects for(int i=0; i<numberOfRaceCars; i++) { racecars[i] = new RaceCar(laps, args[i]); } //Call start() on each Thread for(int i=0; i<numberOfRaceCars; i++) { racecars[i].start(); try { racecars[i].join(); //This is where I tried to using join() //It just blocks all other threads until the current //thread finishes. } catch(InterruptedException e) { e.printStackTrace(); } } //This is the line I want to execute after all other Threads have finished System.out.println("It's Over!"); } Thanks for the help guys! Eric

  Read the article

• CLR via C# 3rd Edition is out

  - by Abhijeet Patel

  Time for some book news update. CLR via C#, 3rd Edition seems to have been out for a little while now. The book was released in early Feb this year, and needless to say my copy is on it’s way. I can barely wait to dig in and chew on the goodies that one of the best technical authors and software professionals I respect has in store. The 2nd edition of the book was an absolute treat and this edition promises to be no less. Here is a brief description of what’s new and updated from the 2nd edition. Part I – CLR Basics Chapter 1-The CLR’s Execution Model Added about discussion about C#’s /optimize and /debug switches and how they relate to each other. Chapter 2-Building, Packaging, Deploying, and Administering Applications and Types Improved discussion about Win32 manifest information and version resource information. Chapter 3-Shared Assemblies and Strongly Named Assemblies Added discussion of TypeForwardedToAttribute and TypeForwardedFromAttribute. Part II – Designing Types Chapter 4-Type Fundamentals No new topics. Chapter 5-Primitive, Reference, and Value Types Enhanced discussion of checked and unchecked code and added discussion of new BigInteger type. Also added discussion of C# 4.0’s dynamic primitive type. Chapter 6-Type and Member Basics No new topics. Chapter 7-Constants and Fields No new topics. Chapter 8-Methods Added discussion of extension methods and partial methods. Chapter 9-Parameters Added discussion of optional/named parameters and implicitly-typed local variables. Chapter 10-Properties Added discussion of automatically-implemented properties, properties and the Visual Studio debugger, object and collection initializers, anonymous types, the System.Tuple type and the ExpandoObject type. Chapter 11-Events Added discussion of events and thread-safety as well as showing a cool extension method to simplify the raising of an event. Chapter 12-Generics Added discussion of delegate and interface generic type argument variance. Chapter 13-Interfaces No new topics. Part III – Essential Types Chapter 14-Chars, Strings, and Working with Text No new topics. Chapter 15-Enums Added coverage of new Enum and Type methods to access enumerated type instances. Chapter 16-Arrays Added new section on initializing array elements. Chapter 17-Delegates Added discussion of using generic delegates to avoid defining new delegate types. Also added discussion of lambda expressions. Chapter 18-Attributes No new topics. Chapter 19-Nullable Value Types Added discussion on performance. Part IV – CLR Facilities Chapter 20-Exception Handling and State Management This chapter has been completely rewritten. It is now about exception handling and state management. It includes discussions of code contracts and constrained execution regions (CERs). It also includes a new section on trade-offs between writing productive code and reliable code. Chapter 21-Automatic Memory Management Added discussion of C#’s fixed state and how it works to pin objects in the heap. Rewrote the code for weak delegates so you can use them with any class that exposes an event (the class doesn’t have to support weak delegates itself). Added discussion on the new ConditionalWeakTable class, GC Collection modes, Full GC notifications, garbage collection modes and latency modes. I also include a new sample showing how your application can receive notifications whenever Generation 0 or 2 collections occur. Chapter 22-CLR Hosting and AppDomains Added discussion of side-by-side support allowing multiple CLRs to be loaded in a single process. Added section on the performance of using MarshalByRefObject-derived types. Substantially rewrote the section on cross-AppDomain communication. Added section on AppDomain Monitoring and first chance exception notifications. Updated the section on the AppDomainManager class. Chapter 23-Assembly Loading and Reflection Added section on how to deploy a single file with dependent assemblies embedded inside it. Added section comparing reflection invoke vs bind/invoke vs bind/create delegate/invoke vs C#’s dynamic type. Chapter 24-Runtime Serialization This is a whole new chapter that was not in the 2nd Edition. Part V – Threading Chapter 25-Threading Basics Whole new chapter motivating why Windows supports threads, thread overhead, CPU trends, NUMA Architectures, the relationship between CLR threads and Windows threads, the Thread class, reasons to use threads, thread scheduling and priorities, foreground thread vs background threads. Chapter 26-Performing Compute-Bound Asynchronous Operations Whole new chapter explaining the CLR’s thread pool. This chapter covers all the new .NET 4.0 constructs including cooperative cancelation, Tasks, the aralle class, parallel language integrated query, timers, how the thread pool manages its threads, cache lines and false sharing. Chapter 27-Performing I/O-Bound Asynchronous Operations Whole new chapter explaining how Windows performs synchronous and asynchronous I/O operations. Then, I go into the CLR’s Asynchronous Programming Model, my AsyncEnumerator class, the APM and exceptions, Applications and their threading models, implementing a service asynchronously, the APM and Compute-bound operations, APM considerations, I/O request priorities, converting the APM to a Task, the event-based Asynchronous Pattern, programming model soup. Chapter 28-Primitive Thread Synchronization Constructs Whole new chapter discusses class libraries and thread safety, primitive user-mode, kernel-mode constructs, and data alignment. Chapter 29-Hybrid Thread Synchronization Constructs Whole new chapter discussion various hybrid constructs such as ManualResetEventSlim, SemaphoreSlim, CountdownEvent, Barrier, ReaderWriterLock(Slim), OneManyResourceLock, Monitor, 3 ways to solve the double-check locking technique, .NET 4.0’s Lazy and LazyInitializer classes, the condition variable pattern, .NET 4.0’s concurrent collection classes, the ReaderWriterGate and SyncGate classes.

  Read the article

• Parallelism implies concurrency but not the other way round right?

  - by Cedric Martin

  I often read that parallelism and concurrency are different things. Very often the answerers/commenters go as far as writing that they're two entirely different things. Yet in my view they're related but I'd like some clarification on that. For example if I'm on a multi-core CPU and manage to divide the computation into x smaller computation (say using fork/join) each running in its own thread, I'll have a program that is both doing parallel computation (because supposedly at any point in time several threads are going to run on several cores) and being concurrent right? While if I'm simply using, say, Java and dealing with UI events and repaints on the Event Dispatch Thread plus running the only thread I created myself, I'll have a program that is concurrent (EDT + GC thread + my main thread etc.) but not parallel. I'd like to know if I'm getting this right and if parallelism (on a "single but multi-cores" system) always implies concurrency or not? Also, are multi-threaded programs running on multi-cores CPU but where the different threads are doing totally different computation considered to be using "parallelism"?

  Read the article

• Is true multithreading really necessary?

  - by Jonathan Graef

  So yeah, I'm creating a programming language. And the language allows multiple threads. But, all threads are synchronized with a global interpreter lock, which means only one thread is allowed to execute at a time. The only way to get the threads to switch off is to explicitly tell the current thread to wait, which allows another thread to execute. Parallel processing is of course possible by spawning multiple processes, but the variables and objects in one process cannot be accessed from another. However the language does have a fairly efficient IPC interface for communicating between processes. My question is: Would there ever be a reason to have multiple, unsynchronized threads within a single process (thus circumventing the GIL)? Why not just put thread.wait() statements in key positions in the program logic (presuming thread.wait() isn't a CPU hog, of course)? I understand that certain other languages that use a GIL have processor scheduling issues (cough Python), but they have all been resolved.

  Read the article

• What if we run out of stack space in C# or Python?

  - by dotneteer

  Supposing we are running a recursive algorithm on a very large data set that requires, say, 1 million recursive calls. Normally, one would solve such a large problem by converting recursion to a loop and a stack, but what if we do not want to or cannot rewrite the algorithm? Python has the sys.setrecursionlimit(int) method to set the number of recursions. However, this is only part of the story; the program can still run our of stack space. C# does not have a equivalent method. Fortunately, both C# and Python have option to set the stack space when creating a thread. In C#, there is an overloaded constructor for the Thread class that accepts a parameter for the stack size: Thread t = new Thread(work, stackSize); In Python, we can set the stack size by calling: threading.stack_size(67108864) We can then run our work under a new thread with increased stack size.

  Read the article

• Multithreading synchronization interview question: Find n words given m threads

  - by rplusg

  I came across this question: You are given a paragraph , which contain n number of words, you are given m threads. What you need to do is , each thread should print one word and give the control to next thread, this way each thread will keep on printing one word , in case last thread come, it should invoke the first thread. Printing will repeat until all the words are printed in paragraph. Finally all threads should exit gracefully. What kind of synchronization will use? I strongly feel we cannot take any advantage of threads here but interviewer is trying to understand my synchronization skills? No need of code, just put some thoughts. I will implement by myself.

  Read the article

• Data Binding to Attached Properties

  - by Chris Gardner

  Originally posted on: http://geekswithblogs.net/freestylecoding/archive/2013/06/14/data-binding-to-attached-properties.aspx When I was working on my C#/XAML game framework, I discovered I wanted to try to data bind my sprites to background objects. That way, I could update my objects and the draw functionality would take care of the work for me. After a little experimenting and web searching, it appeared this concept was an impossible dream. Of course, when has that ever stopped me? In my typical way, I started to massively dive down the rabbit hole. I created a sprite on a canvas, and I bound it to a background object. <Canvas Name="GameField" Background="Black"> <Image Name="PlayerStrite" Source="Assets/Ship.png" Width="50" Height="50" Canvas.Left="{Binding X}" Canvas.Top="{Binding Y}"/> </Canvas> Now, we wire the UI item to the background item. public MainPage() { this.InitializeComponent(); this.Loaded += StartGame; }   void StartGame( object sender, RoutedEventArgs e ) { BindingPlayer _Player = new BindingPlayer(); _Player.X = Window.Current.Bounds.Height - PlayerSprite.Height; _Player.X = ( Window.Current.Bounds.Width - PlayerSprite.Width ) / 2.0; } Of course, now we need to actually have our background object. public class BindingPlayer : INotifyPropertyChanged { private double m_X; public double X { get { return m_X; } set { m_X = value; NotifyPropertyChanged(); } }   private double m_Y; public double Y { get { return m_Y; } set { m_Y = value; NotifyPropertyChanged(); } }   public event PropertyChangedEventHandler PropertyChanged; protected void NotifyPropertyChanged( [CallerMemberName] string p_PropertyName = null ) { if( PropertyChanged != null ) PropertyChanged( this, new PropertyChangedEventArgs( p_PropertyName ) ); } } I fired this baby up, and my sprite was correctly positioned on the screen. Maybe the sky wasn't falling after all. Wouldn't it be great if that was the case? I created some code to allow me to move the sprite, but nothing happened. This seems odd. So, I start debugging the application and stepping through code. Everything appears to be working. Time to dig a little deeper. After much profanity was spewed, I stumbled upon a breakthrough. The code only looked like it was working. What was really happening is that there was an exception being thrown in the background thread that I never saw. Apparently, the key call was the one to PropertyChanged. If PropertyChanged is not called on the UI thread, the UI thread ignores the call. Actually, it throws an exception and the background thread silently crashes. Of course, you'll never see this unless you're looking REALLY carefully. This seemed to be a simple problem. I just need to marshal this to the UI thread. Unfortunately, this object has no knowledge of this mythical UI Thread in which we speak. So, I had to pull the UI Thread out of thin air. Let's change our PropertyChanged call to look this. public event PropertyChangedEventHandler PropertyChanged; protected void NotifyPropertyChanged( [CallerMemberName] string p_PropertyName = null ) { if( PropertyChanged != null ) Windows.ApplicationModel.Core.CoreApplication.MainView.CoreWindow.Dispatcher.RunAsync( Windows.UI.Core.CoreDispatcherPriority.Normal, new Windows.UI.Core.DispatchedHandler( () => { PropertyChanged( this, new PropertyChangedEventArgs( p_PropertyName ) ); } ) ); } Now, we raised our notification on the UI thread. Everything is fine, people are happy, and the world moves on. You may have noticed that I didn't await my call to the dispatcher. This was intentional. If I am trying to update a slew of sprites, I don't want thread being hung while I wait my turn. Thus, I send the message and move on. It is worth nothing that this is NOT the most efficient way to do this for game programming. We'll get to that in another blog post. However, it is perfectly acceptable for a business app that is running a background task that would like to notify the UI thread of progress on a periodic basis. It is worth noting that this code was written for a Windows Store App. You can do the same thing with WP8 and WPF. The call to the marshaler changes, but it is the same idea.

  Read the article

• SmS Gateways - How do other sites do it? [closed]

  - by chobo2

  Possible Duplicate: Send and Receive SMS from my Website I would love to have a feature on my site that sends Email reminders and SmS(text messages) to people mobile phones. I been searching around and all I am finding is api's that charge money per SmS message(as low as 1cent per message). However even at 1cent per message that is still too much. The amount of money I am charging per year could be servilely eroded by just the Sms messages along. I could of course charge more money for my service or have an add on for SmS messages but I don't think either would work as most people expect it to be free feature and if they have to pay anything that is because of their carrier charging them not the website. How do other sites do it? I guessing companies like google have their own gateway providers or something like that. But how about smaller sites what do they do? I can't see them paying per sms text message.

  Read the article

• Init.d script gets return code 1 when calling itself, how can I get output?

  - by Per

  My question is, how can I modify the script so that it will tell me what goes wrong? The scenario is this: I'm trying to get Sonatype Nexus to start as a service in Ubuntu 10.04, and it just will not work. (I'm not looking for help on how to run Nexus, but on how to get some useful output from a script) It works when invoking it with sudo /etc/init.d/nexus start but fails when using sudo service nexus start I have run the update-rc.d command on it, and done everything according to instructions. The nexus init.d-script has a point where it calls itself when it detects that it should run as another user ('nexus'): su -m $RUN_AS_USER -c "\"$REALPATH\" $2" which expands to su -m nexus -c '"/opt/nexus-2.0.2/bin/jsw/linux-x86-64/nexus" start' when adding the -x debug flag to the script. This command results in return code 1. It never executes - I've set -x debug flag on the script, placed echo commands with redirect to file at the start of script to trace, etc. I cannot get any output telling me why the command will not execute. I've tried appending redirect to file after the above script line, inside the quotes, outside, any way I could imagine. All info I can get is by inserting a line echo $? after the su line, which outputs '1'. Is there a way I can see what happens when the su command runs?

  Read the article

• How to write specs with MSpec for code that changes Thread.CurrentPrincipal?

  - by Dan Jensen

  I've been converting some old specs to MSpec (were using NUnit/SpecUnit). The specs are for a view model, and the view model in question does some custom security checking. We have a helper method in our specs which will setup fake security credentials for the Thread.CurrentPrincipal. This worked fine in the old unit tests, but fails in MSpec. Specifically, I'm getting this exception: "System.Runtime.Serialization.SerializationException: Type is not resolved for member" It happens when part of the SUT tries to read the app config file. If I comment out the line which sets the CurrentPrincipal (or simply call it after the part that checks the config file), the error goes away, but the tests fail due to lack of credentials. Similarly, if I set the CurrentPrincipal to null, the error goes away, but again the tests fail because the credentials aren't set. I've googled this, and found some posts about making sure the custom principal is serializable when it crosses AppDomain boundaries (usually in reference to web apps). In our case, this is not a web app, and I'm not crossing any AppDomains. Our pincipal object is also serializable. I downloaded the source for MSpec, and found that the ConsoleRunner calls a class named AppDomainRunner. I haven't debugged into it, but it looks like it's running the specs in different app domains. So does anyone have any ideas on how I can overcome this? I really like MSpec, and would love to use it exclusively. But I need to be able to supply fake security credentials while running the tests. Thanks! Update: here's the spec class: [Subject(typeof(CountryPickerViewModel))] public class When_the_user_makes_a_selection : PickerViewModelSpecsBase { protected static CountryPickerViewModel picker; Establish context = () => { SetupFakeSecurityCredentials(); CreateFactoryStubs(); StubLookupServicer<ICountryLookupServicer>() .WithData(BuildActiveItems(new [] { "USA", "UK" })); picker = new CountryPickerViewModel(ViewFactory, ViewModelFactory, BusinessLogicFactory, CacheFactory); }; Because of = () => picker.SelectedItem = picker.Items[0]; Behaves_like<Picker_that_has_a_selected_item> a_picker_with_a_selection; } We have a number of these "picker" view models, all of which exhibit some common behavior. So I'm using the Behaviors feature of MSpec. This particular class is simulating the user selecting something from the (WPF) control which is bound to this VM. The SetupFakeSecurityCredentials() method is simply setting Thread.CurrentPrincipal to an instance of our custom principal, where the prinipal has been populated will full-access rights. Here's a fake CountryPickerViewModel which is enough to cause the error: public class CountryPickerViewModel { public CountryPickerViewModel(IViewFactory viewFactory, IViewModelFactory viewModelFactory, ICoreBusinessLogicFactory businessLogicFactory, ICacheFactory cacheFactory) { Items = new Collection<int>(); var validator = ValidationFactory.CreateValidator<object>(); } public int SelectedItem { get; set; } public Collection<int> Items { get; private set; } } It's the ValidationFactory call which blows up. ValidationFactory is an Enterprise Library object, which tries to access the config.

  Read the article

• Using R to Analyze G1GC Log Files

  - by user12620111

  Using R to Analyze G1GC Log Files body, td { font-family: sans-serif; background-color: white; font-size: 12px; margin: 8px; } tt, code, pre { font-family: 'DejaVu Sans Mono', 'Droid Sans Mono', 'Lucida Console', Consolas, Monaco, monospace; } h1 { font-size:2.2em; } h2 { font-size:1.8em; } h3 { font-size:1.4em; } h4 { font-size:1.0em; } h5 { font-size:0.9em; } h6 { font-size:0.8em; } a:visited { color: rgb(50%, 0%, 50%); } pre { margin-top: 0; max-width: 95%; border: 1px solid #ccc; white-space: pre-wrap; } pre code { display: block; padding: 0.5em; } code.r, code.cpp { background-color: #F8F8F8; } table, td, th { border: none; } blockquote { color:#666666; margin:0; padding-left: 1em; border-left: 0.5em #EEE solid; } hr { height: 0px; border-bottom: none; border-top-width: thin; border-top-style: dotted; border-top-color: #999999; } @media print { * { background: transparent !important; color: black !important; filter:none !important; -ms-filter: none !important; } body { font-size:12pt; max-width:100%; } a, a:visited { text-decoration: underline; } hr { visibility: hidden; page-break-before: always; } pre, blockquote { padding-right: 1em; page-break-inside: avoid; } tr, img { page-break-inside: avoid; } img { max-width: 100% !important; } @page :left { margin: 15mm 20mm 15mm 10mm; } @page :right { margin: 15mm 10mm 15mm 20mm; } p, h2, h3 { orphans: 3; widows: 3; } h2, h3 { page-break-after: avoid; } } pre .operator, pre .paren { color: rgb(104, 118, 135) } pre .literal { color: rgb(88, 72, 246) } pre .number { color: rgb(0, 0, 205); } pre .comment { color: rgb(76, 136, 107); } pre .keyword { color: rgb(0, 0, 255); } pre .identifier { color: rgb(0, 0, 0); } pre .string { color: rgb(3, 106, 7); } var hljs=new function(){function m(p){return p.replace(/&/gm,"&").replace(/"}while(y.length||w.length){var v=u().splice(0,1)[0];z+=m(x.substr(q,v.offset-q));q=v.offset;if(v.event=="start"){z+=t(v.node);s.push(v.node)}else{if(v.event=="stop"){var p,r=s.length;do{r--;p=s[r];z+=("")}while(p!=v.node);s.splice(r,1);while(r'+M[0]+""}else{r+=M[0]}O=P.lR.lastIndex;M=P.lR.exec(L)}return r+L.substr(O,L.length-O)}function J(L,M){if(M.sL&&e[M.sL]){var r=d(M.sL,L);x+=r.keyword_count;return r.value}else{return F(L,M)}}function I(M,r){var L=M.cN?'':"";if(M.rB){y+=L;M.buffer=""}else{if(M.eB){y+=m(r)+L;M.buffer=""}else{y+=L;M.buffer=r}}D.push(M);A+=M.r}function G(N,M,Q){var R=D[D.length-1];if(Q){y+=J(R.buffer+N,R);return false}var P=q(M,R);if(P){y+=J(R.buffer+N,R);I(P,M);return P.rB}var L=v(D.length-1,M);if(L){var O=R.cN?"":"";if(R.rE){y+=J(R.buffer+N,R)+O}else{if(R.eE){y+=J(R.buffer+N,R)+O+m(M)}else{y+=J(R.buffer+N+M,R)+O}}while(L1){O=D[D.length-2].cN?"":"";y+=O;L--;D.length--}var r=D[D.length-1];D.length--;D[D.length-1].buffer="";if(r.starts){I(r.starts,"")}return R.rE}if(w(M,R)){throw"Illegal"}}var E=e[B];var D=[E.dM];var A=0;var x=0;var y="";try{var s,u=0;E.dM.buffer="";do{s=p(C,u);var t=G(s[0],s[1],s[2]);u+=s[0].length;if(!t){u+=s[1].length}}while(!s[2]);if(D.length1){throw"Illegal"}return{r:A,keyword_count:x,value:y}}catch(H){if(H=="Illegal"){return{r:0,keyword_count:0,value:m(C)}}else{throw H}}}function g(t){var p={keyword_count:0,r:0,value:m(t)};var r=p;for(var q in e){if(!e.hasOwnProperty(q)){continue}var s=d(q,t);s.language=q;if(s.keyword_count+s.rr.keyword_count+r.r){r=s}if(s.keyword_count+s.rp.keyword_count+p.r){r=p;p=s}}if(r.language){p.second_best=r}return p}function i(r,q,p){if(q){r=r.replace(/^((]+|\t)+)/gm,function(t,w,v,u){return w.replace(/\t/g,q)})}if(p){r=r.replace(/\n/g,"")}return r}function n(t,w,r){var x=h(t,r);var v=a(t);var y,s;if(v){y=d(v,x)}else{return}var q=c(t);if(q.length){s=document.createElement("pre");s.innerHTML=y.value;y.value=k(q,c(s),x)}y.value=i(y.value,w,r);var u=t.className;if(!u.match("(\\s|^)(language-)?"+v+"(\\s|$)")){u=u?(u+" "+v):v}if(/MSIE [678]/.test(navigator.userAgent)&&t.tagName=="CODE"&&t.parentNode.tagName=="PRE"){s=t.parentNode;var p=document.createElement("div");p.innerHTML=""+y.value+"";t=p.firstChild.firstChild;p.firstChild.cN=s.cN;s.parentNode.replaceChild(p.firstChild,s)}else{t.innerHTML=y.value}t.className=u;t.result={language:v,kw:y.keyword_count,re:y.r};if(y.second_best){t.second_best={language:y.second_best.language,kw:y.second_best.keyword_count,re:y.second_best.r}}}function o(){if(o.called){return}o.called=true;var r=document.getElementsByTagName("pre");for(var p=0;p|=||=||=|\\?|\\[|\\{|\\(|\\^|\\^=|\\||\\|=|\\|\\||~";this.ER="(?![\\s\\S])";this.BE={b:"\\\\.",r:0};this.ASM={cN:"string",b:"'",e:"'",i:"\\n",c:[this.BE],r:0};this.QSM={cN:"string",b:'"',e:'"',i:"\\n",c:[this.BE],r:0};this.CLCM={cN:"comment",b:"//",e:"$"};this.CBLCLM={cN:"comment",b:"/\\*",e:"\\*/"};this.HCM={cN:"comment",b:"#",e:"$"};this.NM={cN:"number",b:this.NR,r:0};this.CNM={cN:"number",b:this.CNR,r:0};this.BNM={cN:"number",b:this.BNR,r:0};this.inherit=function(r,s){var p={};for(var q in r){p[q]=r[q]}if(s){for(var q in s){p[q]=s[q]}}return p}}();hljs.LANGUAGES.cpp=function(){var a={keyword:{"false":1,"int":1,"float":1,"while":1,"private":1,"char":1,"catch":1,"export":1,virtual:1,operator:2,sizeof:2,dynamic_cast:2,typedef:2,const_cast:2,"const":1,struct:1,"for":1,static_cast:2,union:1,namespace:1,unsigned:1,"long":1,"throw":1,"volatile":2,"static":1,"protected":1,bool:1,template:1,mutable:1,"if":1,"public":1,friend:2,"do":1,"return":1,"goto":1,auto:1,"void":2,"enum":1,"else":1,"break":1,"new":1,extern:1,using:1,"true":1,"class":1,asm:1,"case":1,typeid:1,"short":1,reinterpret_cast:2,"default":1,"double":1,register:1,explicit:1,signed:1,typename:1,"try":1,"this":1,"switch":1,"continue":1,wchar_t:1,inline:1,"delete":1,alignof:1,char16_t:1,char32_t:1,constexpr:1,decltype:1,noexcept:1,nullptr:1,static_assert:1,thread_local:1,restrict:1,_Bool:1,complex:1},built_in:{std:1,string:1,cin:1,cout:1,cerr:1,clog:1,stringstream:1,istringstream:1,ostringstream:1,auto_ptr:1,deque:1,list:1,queue:1,stack:1,vector:1,map:1,set:1,bitset:1,multiset:1,multimap:1,unordered_set:1,unordered_map:1,unordered_multiset:1,unordered_multimap:1,array:1,shared_ptr:1}};return{dM:{k:a,i:"",k:a,r:10,c:["self"]}]}}}();hljs.LANGUAGES.r={dM:{c:[hljs.HCM,{cN:"number",b:"\\b0[xX][0-9a-fA-F]+[Li]?\\b",e:hljs.IMMEDIATE_RE,r:0},{cN:"number",b:"\\b\\d+(?:[eE][+\\-]?\\d*)?L\\b",e:hljs.IMMEDIATE_RE,r:0},{cN:"number",b:"\\b\\d+\\.(?!\\d)(?:i\\b)?",e:hljs.IMMEDIATE_RE,r:1},{cN:"number",b:"\\b\\d+(?:\\.\\d*)?(?:[eE][+\\-]?\\d*)?i?\\b",e:hljs.IMMEDIATE_RE,r:0},{cN:"number",b:"\\.\\d+(?:[eE][+\\-]?\\d*)?i?\\b",e:hljs.IMMEDIATE_RE,r:1},{cN:"keyword",b:"(?:tryCatch|library|setGeneric|setGroupGeneric)\\b",e:hljs.IMMEDIATE_RE,r:10},{cN:"keyword",b:"\\.\\.\\.",e:hljs.IMMEDIATE_RE,r:10},{cN:"keyword",b:"\\.\\.\\d+(?![\\w.])",e:hljs.IMMEDIATE_RE,r:10},{cN:"keyword",b:"\\b(?:function)",e:hljs.IMMEDIATE_RE,r:2},{cN:"keyword",b:"(?:if|in|break|next|repeat|else|for|return|switch|while|try|stop|warning|require|attach|detach|source|setMethod|setClass)\\b",e:hljs.IMMEDIATE_RE,r:1},{cN:"literal",b:"(?:NA|NA_integer_|NA_real_|NA_character_|NA_complex_)\\b",e:hljs.IMMEDIATE_RE,r:10},{cN:"literal",b:"(?:NULL|TRUE|FALSE|T|F|Inf|NaN)\\b",e:hljs.IMMEDIATE_RE,r:1},{cN:"identifier",b:"[a-zA-Z.][a-zA-Z0-9._]*\\b",e:hljs.IMMEDIATE_RE,r:0},{cN:"operator",b:"|=||   Using R to Analyze G1GC Log Files   Using R to Analyze G1GC Log Files Introduction Working in Oracle Platform Integration gives an engineer opportunities to work on a wide array of technologies. My team’s goal is to make Oracle applications run best on the Solaris/SPARC platform. When looking for bottlenecks in a modern applications, one needs to be aware of not only how the CPUs and operating system are executing, but also network, storage, and in some cases, the Java Virtual Machine. I was recently presented with about 1.5 GB of Java Garbage First Garbage Collector log file data. If you’re not familiar with the subject, you might want to review Garbage First Garbage Collector Tuning by Monica Beckwith. The customer had been running Java HotSpot 1.6.0_31 to host a web application server. I was told that the Solaris/SPARC server was running a Java process launched using a commmand line that included the following flags: -d64 -Xms9g -Xmx9g -XX:+UseG1GC -XX:MaxGCPauseMillis=200 -XX:InitiatingHeapOccupancyPercent=80 -XX:PermSize=256m -XX:MaxPermSize=256m -XX:+PrintGC -XX:+PrintGCTimeStamps -XX:+PrintHeapAtGC -XX:+PrintGCDateStamps -XX:+PrintFlagsFinal -XX:+DisableExplicitGC -XX:+UnlockExperimentalVMOptions -XX:ParallelGCThreads=8 Several sources on the internet indicate that if I were to print out the 1.5 GB of log files, it would require enough paper to fill the bed of a pick up truck. Of course, it would be fruitless to try to scan the log files by hand. Tools will be required to summarize the contents of the log files. Others have encountered large Java garbage collection log files. There are existing tools to analyze the log files: IBM’s GC toolkit The chewiebug GCViewer gchisto HPjmeter Instead of using one of the other tools listed, I decide to parse the log files with standard Unix tools, and analyze the data with R. Data Cleansing The log files arrived in two different formats. I guess that the difference is that one set of log files was generated using a more verbose option, maybe -XX:+PrintHeapAtGC, and the other set of log files was generated without that option. Format 1 In some of the log files, the log files with the less verbose format, a single trace, i.e. the report of a singe garbage collection event, looks like this: {Heap before GC invocations=12280 (full 61): garbage-first heap total 9437184K, used 7499918K [0xfffffffd00000000, 0xffffffff40000000, 0xffffffff40000000) region size 4096K, 1 young (4096K), 0 survivors (0K) compacting perm gen total 262144K, used 144077K [0xffffffff40000000, 0xffffffff50000000, 0xffffffff50000000) the space 262144K, 54% used [0xffffffff40000000, 0xffffffff48cb3758, 0xffffffff48cb3800, 0xffffffff50000000) No shared spaces configured. 2014-05-14T07:24:00.988-0700: 60586.353: [GC pause (young) 7324M->7320M(9216M), 0.1567265 secs] Heap after GC invocations=12281 (full 61): garbage-first heap total 9437184K, used 7496533K [0xfffffffd00000000, 0xffffffff40000000, 0xffffffff40000000) region size 4096K, 0 young (0K), 0 survivors (0K) compacting perm gen total 262144K, used 144077K [0xffffffff40000000, 0xffffffff50000000, 0xffffffff50000000) the space 262144K, 54% used [0xffffffff40000000, 0xffffffff48cb3758, 0xffffffff48cb3800, 0xffffffff50000000) No shared spaces configured. } A simple grep can be used to extract a summary: $ grep "\[ GC pause (young" g1gc.log 2014-05-13T13:24:35.091-0700: 3.109: [GC pause (young) 20M->5029K(9216M), 0.0146328 secs] 2014-05-13T13:24:35.440-0700: 3.459: [GC pause (young) 9125K->6077K(9216M), 0.0086723 secs] 2014-05-13T13:24:37.581-0700: 5.599: [GC pause (young) 25M->8470K(9216M), 0.0203820 secs] 2014-05-13T13:24:42.686-0700: 10.704: [GC pause (young) 44M->15M(9216M), 0.0288848 secs] 2014-05-13T13:24:48.941-0700: 16.958: [GC pause (young) 51M->20M(9216M), 0.0491244 secs] 2014-05-13T13:24:56.049-0700: 24.066: [GC pause (young) 92M->26M(9216M), 0.0525368 secs] 2014-05-13T13:25:34.368-0700: 62.383: [GC pause (young) 602M->68M(9216M), 0.1721173 secs] But that format wasn't easily read into R, so I needed to be a bit more tricky. I used the following Unix command to create a summary file that was easy for R to read. $ echo "SecondsSinceLaunch BeforeSize AfterSize TotalSize RealTime" $ grep "\[GC pause (young" g1gc.log | grep -v mark | sed -e 's/[A-SU-z\(\),]/ /g' -e 's/->/ /' -e 's/: / /g' | more SecondsSinceLaunch BeforeSize AfterSize TotalSize RealTime 2014-05-13T13:24:35.091-0700 3.109 20 5029 9216 0.0146328 2014-05-13T13:24:35.440-0700 3.459 9125 6077 9216 0.0086723 2014-05-13T13:24:37.581-0700 5.599 25 8470 9216 0.0203820 2014-05-13T13:24:42.686-0700 10.704 44 15 9216 0.0288848 2014-05-13T13:24:48.941-0700 16.958 51 20 9216 0.0491244 2014-05-13T13:24:56.049-0700 24.066 92 26 9216 0.0525368 2014-05-13T13:25:34.368-0700 62.383 602 68 9216 0.1721173 Format 2 In some of the log files, the log files with the more verbose format, a single trace, i.e. the report of a singe garbage collection event, was more complicated than Format 1. Here is a text file with an example of a single G1GC trace in the second format. As you can see, it is quite complicated. It is nice that there is so much information available, but the level of detail can be overwhelming. I wrote this awk script (download) to summarize each trace on a single line. #!/usr/bin/env awk -f BEGIN { printf("SecondsSinceLaunch IncrementalCount FullCount UserTime SysTime RealTime BeforeSize AfterSize TotalSize\n") } ###################### # Save count data from lines that are at the start of each G1GC trace. # Each trace starts out like this: # {Heap before GC invocations=14 (full 0): # garbage-first heap total 9437184K, used 325496K [0xfffffffd00000000, 0xffffffff40000000, 0xffffffff40000000) ###################### /{Heap.*full/{ gsub ( "\\)" , "" ); nf=split($0,a,"="); split(a[2],b," "); getline; if ( match($0, "first") ) { G1GC=1; IncrementalCount=b[1]; FullCount=substr( b[3], 1, length(b[3])-1 ); } else { G1GC=0; } } ###################### # Pull out time stamps that are in lines with this format: # 2014-05-12T14:02:06.025-0700: 94.312: [GC pause (young), 0.08870154 secs] ###################### /GC pause/ { DateTime=$1; SecondsSinceLaunch=substr($2, 1, length($2)-1); } ###################### # Heap sizes are in lines that look like this: # [ 4842M->4838M(9216M)] ###################### /\[ .*]$/ { gsub ( "\\[" , "" ); gsub ( "\ \]" , "" ); gsub ( "->" , " " ); gsub ( "\\( " , " " ); gsub ( "\ \)" , " " ); split($0,a," "); if ( split(a[1],b,"M") > 1 ) {BeforeSize=b[1]*1024;} if ( split(a[1],b,"K") > 1 ) {BeforeSize=b[1];} if ( split(a[2],b,"M") > 1 ) {AfterSize=b[1]*1024;} if ( split(a[2],b,"K") > 1 ) {AfterSize=b[1];} if ( split(a[3],b,"M") > 1 ) {TotalSize=b[1]*1024;} if ( split(a[3],b,"K") > 1 ) {TotalSize=b[1];} } ###################### # Emit an output line when you find input that looks like this: # [Times: user=1.41 sys=0.08, real=0.24 secs] ###################### /\[Times/ { if (G1GC==1) { gsub ( "," , "" ); split($2,a,"="); UserTime=a[2]; split($3,a,"="); SysTime=a[2]; split($4,a,"="); RealTime=a[2]; print DateTime,SecondsSinceLaunch,IncrementalCount,FullCount,UserTime,SysTime,RealTime,BeforeSize,AfterSize,TotalSize; G1GC=0; } } The resulting summary is about 25X smaller that the original file, but still difficult for a human to digest. SecondsSinceLaunch IncrementalCount FullCount UserTime SysTime RealTime BeforeSize AfterSize TotalSize ... 2014-05-12T18:36:34.669-0700: 3985.744 561 0 0.57 0.06 0.16 1724416 1720320 9437184 2014-05-12T18:36:34.839-0700: 3985.914 562 0 0.51 0.06 0.19 1724416 1720320 9437184 2014-05-12T18:36:35.069-0700: 3986.144 563 0 0.60 0.04 0.27 1724416 1721344 9437184 2014-05-12T18:36:35.354-0700: 3986.429 564 0 0.33 0.04 0.09 1725440 1722368 9437184 2014-05-12T18:36:35.545-0700: 3986.620 565 0 0.58 0.04 0.17 1726464 1722368 9437184 2014-05-12T18:36:35.726-0700: 3986.801 566 0 0.43 0.05 0.12 1726464 1722368 9437184 2014-05-12T18:36:35.856-0700: 3986.930 567 0 0.30 0.04 0.07 1726464 1723392 9437184 2014-05-12T18:36:35.947-0700: 3987.023 568 0 0.61 0.04 0.26 1727488 1723392 9437184 2014-05-12T18:36:36.228-0700: 3987.302 569 0 0.46 0.04 0.16 1731584 1724416 9437184 Reading the Data into R Once the GC log data had been cleansed, either by processing the first format with the shell script, or by processing the second format with the awk script, it was easy to read the data into R. g1gc.df = read.csv("summary.txt", row.names = NULL, stringsAsFactors=FALSE,sep="") str(g1gc.df) ## 'data.frame': 8307 obs. of 10 variables: ## $ row.names : chr "2014-05-12T14:00:32.868-0700:" "2014-05-12T14:00:33.179-0700:" "2014-05-12T14:00:33.677-0700:" "2014-05-12T14:00:35.538-0700:" ... ## $ SecondsSinceLaunch: num 1.16 1.47 1.97 3.83 6.1 ... ## $ IncrementalCount : int 0 1 2 3 4 5 6 7 8 9 ... ## $ FullCount : int 0 0 0 0 0 0 0 0 0 0 ... ## $ UserTime : num 0.11 0.05 0.04 0.21 0.08 0.26 0.31 0.33 0.34 0.56 ... ## $ SysTime : num 0.04 0.01 0.01 0.05 0.01 0.06 0.07 0.06 0.07 0.09 ... ## $ RealTime : num 0.02 0.02 0.01 0.04 0.02 0.04 0.05 0.04 0.04 0.06 ... ## $ BeforeSize : int 8192 5496 5768 22528 24576 43008 34816 53248 55296 93184 ... ## $ AfterSize : int 1400 1672 2557 4907 7072 14336 16384 18432 19456 21504 ... ## $ TotalSize : int 9437184 9437184 9437184 9437184 9437184 9437184 9437184 9437184 9437184 9437184 ... head(g1gc.df) ## row.names SecondsSinceLaunch IncrementalCount ## 1 2014-05-12T14:00:32.868-0700: 1.161 0 ## 2 2014-05-12T14:00:33.179-0700: 1.472 1 ## 3 2014-05-12T14:00:33.677-0700: 1.969 2 ## 4 2014-05-12T14:00:35.538-0700: 3.830 3 ## 5 2014-05-12T14:00:37.811-0700: 6.103 4 ## 6 2014-05-12T14:00:41.428-0700: 9.720 5 ## FullCount UserTime SysTime RealTime BeforeSize AfterSize TotalSize ## 1 0 0.11 0.04 0.02 8192 1400 9437184 ## 2 0 0.05 0.01 0.02 5496 1672 9437184 ## 3 0 0.04 0.01 0.01 5768 2557 9437184 ## 4 0 0.21 0.05 0.04 22528 4907 9437184 ## 5 0 0.08 0.01 0.02 24576 7072 9437184 ## 6 0 0.26 0.06 0.04 43008 14336 9437184 Basic Statistics Once the data has been read into R, simple statistics are very easy to generate. All of the numbers from high school statistics are available via simple commands. For example, generate a summary of every column: summary(g1gc.df) ## row.names SecondsSinceLaunch IncrementalCount FullCount ## Length:8307 Min. : 1 Min. : 0 Min. : 0.0 ## Class :character 1st Qu.: 9977 1st Qu.:2048 1st Qu.: 0.0 ## Mode :character Median :12855 Median :4136 Median : 12.0 ## Mean :12527 Mean :4156 Mean : 31.6 ## 3rd Qu.:15758 3rd Qu.:6262 3rd Qu.: 61.0 ## Max. :55484 Max. :8391 Max. :113.0 ## UserTime SysTime RealTime BeforeSize ## Min. :0.040 Min. :0.0000 Min. : 0.0 Min. : 5476 ## 1st Qu.:0.470 1st Qu.:0.0300 1st Qu.: 0.1 1st Qu.:5137920 ## Median :0.620 Median :0.0300 Median : 0.1 Median :6574080 ## Mean :0.751 Mean :0.0355 Mean : 0.3 Mean :5841855 ## 3rd Qu.:0.920 3rd Qu.:0.0400 3rd Qu.: 0.2 3rd Qu.:7084032 ## Max. :3.370 Max. :1.5600 Max. :488.1 Max. :8696832 ## AfterSize TotalSize ## Min. : 1380 Min. :9437184 ## 1st Qu.:5002752 1st Qu.:9437184 ## Median :6559744 Median :9437184 ## Mean :5785454 Mean :9437184 ## 3rd Qu.:7054336 3rd Qu.:9437184 ## Max. :8482816 Max. :9437184 Q: What is the total amount of User CPU time spent in garbage collection? sum(g1gc.df$UserTime) ## [1] 6236 As you can see, less than two hours of CPU time was spent in garbage collection. Is that too much? To find the percentage of time spent in garbage collection, divide the number above by total_elapsed_time*CPU_count. In this case, there are a lot of CPU’s and it turns out the the overall amount of CPU time spent in garbage collection isn’t a problem when viewed in isolation. When calculating rates, i.e. events per unit time, you need to ask yourself if the rate is homogenous across the time period in the log file. Does the log file include spikes of high activity that should be separately analyzed? Averaging in data from nights and weekends with data from business hours may alias problems. If you have a reason to suspect that the garbage collection rates include peaks and valleys that need independent analysis, see the “Time Series” section, below. Q: How much garbage is collected on each pass? The amount of heap space that is recovered per GC pass is surprisingly low: At least one collection didn’t recover any data. (“Min.=0”) 25% of the passes recovered 3MB or less. (“1st Qu.=3072”) Half of the GC passes recovered 4MB or less. (“Median=4096”) The average amount recovered was 56MB. (“Mean=56390”) 75% of the passes recovered 36MB or less. (“3rd Qu.=36860”) At least one pass recovered 2GB. (“Max.=2121000”) g1gc.df$Delta = g1gc.df$BeforeSize - g1gc.df$AfterSize summary(g1gc.df$Delta) ## Min. 1st Qu. Median Mean 3rd Qu. Max. ## 0 3070 4100 56400 36900 2120000 Q: What is the maximum User CPU time for a single collection? The worst garbage collection (“Max.”) is many standard deviations away from the mean. The data appears to be right skewed. summary(g1gc.df$UserTime) ## Min. 1st Qu. Median Mean 3rd Qu. Max. ## 0.040 0.470 0.620 0.751 0.920 3.370 sd(g1gc.df$UserTime) ## [1] 0.3966 Basic Graphics Once the data is in R, it is trivial to plot the data with formats including dot plots, line charts, bar charts (simple, stacked, grouped), pie charts, boxplots, scatter plots histograms, and kernel density plots. Histogram of User CPU Time per Collection I don't think that this graph requires any explanation. hist(g1gc.df$UserTime, main="User CPU Time per Collection", xlab="Seconds", ylab="Frequency") Box plot to identify outliers When the initial data is viewed with a box plot, you can see the one crazy outlier in the real time per GC. Save this data point for future analysis and drop the outlier so that it’s not throwing off our statistics. Now the box plot shows many outliers, which will be examined later, using times series analysis. Notice that the scale of the x-axis changes drastically once the crazy outlier is removed. par(mfrow=c(2,1)) boxplot(g1gc.df$UserTime,g1gc.df$SysTime,g1gc.df$RealTime, main="Box Plot of Time per GC\n(dominated by a crazy outlier)", names=c("usr","sys","elapsed"), xlab="Seconds per GC", ylab="Time (Seconds)", horizontal = TRUE, outcol="red") crazy.outlier.df=g1gc.df[g1gc.df$RealTime > 400,] g1gc.df=g1gc.df[g1gc.df$RealTime < 400,] boxplot(g1gc.df$UserTime,g1gc.df$SysTime,g1gc.df$RealTime, main="Box Plot of Time per GC\n(crazy outlier excluded)", names=c("usr","sys","elapsed"), xlab="Seconds per GC", ylab="Time (Seconds)", horizontal = TRUE, outcol="red") box(which = "outer", lty = "solid") Here is the crazy outlier for future analysis: crazy.outlier.df ## row.names SecondsSinceLaunch IncrementalCount ## 8233 2014-05-12T23:15:43.903-0700: 20741 8316 ## FullCount UserTime SysTime RealTime BeforeSize AfterSize TotalSize ## 8233 112 0.55 0.42 488.1 8381440 8235008 9437184 ## Delta ## 8233 146432 R Time Series Data To analyze the garbage collection as a time series, I’ll use Z’s Ordered Observations (zoo). “zoo is the creator for an S3 class of indexed totally ordered observations which includes irregular time series.” require(zoo) ## Loading required package: zoo ## ## Attaching package: 'zoo' ## ## The following objects are masked from 'package:base': ## ## as.Date, as.Date.numeric head(g1gc.df[,1]) ## [1] "2014-05-12T14:00:32.868-0700:" "2014-05-12T14:00:33.179-0700:" ## [3] "2014-05-12T14:00:33.677-0700:" "2014-05-12T14:00:35.538-0700:" ## [5] "2014-05-12T14:00:37.811-0700:" "2014-05-12T14:00:41.428-0700:" options("digits.secs"=3) times=as.POSIXct( g1gc.df[,1], format="%Y-%m-%dT%H:%M:%OS%z:") g1gc.z = zoo(g1gc.df[,-c(1)], order.by=times) head(g1gc.z) ## SecondsSinceLaunch IncrementalCount FullCount ## 2014-05-12 17:00:32.868 1.161 0 0 ## 2014-05-12 17:00:33.178 1.472 1 0 ## 2014-05-12 17:00:33.677 1.969 2 0 ## 2014-05-12 17:00:35.538 3.830 3 0 ## 2014-05-12 17:00:37.811 6.103 4 0 ## 2014-05-12 17:00:41.427 9.720 5 0 ## UserTime SysTime RealTime BeforeSize AfterSize ## 2014-05-12 17:00:32.868 0.11 0.04 0.02 8192 1400 ## 2014-05-12 17:00:33.178 0.05 0.01 0.02 5496 1672 ## 2014-05-12 17:00:33.677 0.04 0.01 0.01 5768 2557 ## 2014-05-12 17:00:35.538 0.21 0.05 0.04 22528 4907 ## 2014-05-12 17:00:37.811 0.08 0.01 0.02 24576 7072 ## 2014-05-12 17:00:41.427 0.26 0.06 0.04 43008 14336 ## TotalSize Delta ## 2014-05-12 17:00:32.868 9437184 6792 ## 2014-05-12 17:00:33.178 9437184 3824 ## 2014-05-12 17:00:33.677 9437184 3211 ## 2014-05-12 17:00:35.538 9437184 17621 ## 2014-05-12 17:00:37.811 9437184 17504 ## 2014-05-12 17:00:41.427 9437184 28672 Example of Two Benchmark Runs in One Log File The data in the following graph is from a different log file, not the one of primary interest to this article. I’m including this image because it is an example of idle periods followed by busy periods. It would be uninteresting to average the rate of garbage collection over the entire log file period. More interesting would be the rate of garbage collect in the two busy periods. Are they the same or different? Your production data may be similar, for example, bursts when employees return from lunch and idle times on weekend evenings, etc. Once the data is in an R Time Series, you can analyze isolated time windows. Clipping the Time Series data Flashing back to our test case… Viewing the data as a time series is interesting. You can see that the work intensive time period is between 9:00 PM and 3:00 AM. Lets clip the data to the interesting period:     par(mfrow=c(2,1)) plot(g1gc.z$UserTime, type="h", main="User Time per GC\nTime: Complete Log File", xlab="Time of Day", ylab="CPU Seconds per GC", col="#1b9e77") clipped.g1gc.z=window(g1gc.z, start=as.POSIXct("2014-05-12 21:00:00"), end=as.POSIXct("2014-05-13 03:00:00")) plot(clipped.g1gc.z$UserTime, type="h", main="User Time per GC\nTime: Limited to Benchmark Execution", xlab="Time of Day", ylab="CPU Seconds per GC", col="#1b9e77") box(which = "outer", lty = "solid") Cumulative Incremental and Full GC count Here is the cumulative incremental and full GC count. When the line is very steep, it indicates that the GCs are repeating very quickly. Notice that the scale on the Y axis is different for full vs. incremental. plot(clipped.g1gc.z[,c(2:3)], main="Cumulative Incremental and Full GC count", xlab="Time of Day", col="#1b9e77") GC Analysis of Benchmark Execution using Time Series data In the following series of 3 graphs: The “After Size” show the amount of heap space in use after each garbage collection. Many Java objects are still referenced, i.e. alive, during each garbage collection. This may indicate that the application has a memory leak, or may indicate that the application has a very large memory footprint. Typically, an application's memory footprint plateau's in the early stage of execution. One would expect this graph to have a flat top. The steep decline in the heap space may indicate that the application crashed after 2:00. The second graph shows that the outliers in real execution time, discussed above, occur near 2:00. when the Java heap seems to be quite full. The third graph shows that Full GCs are infrequent during the first few hours of execution. The rate of Full GC's, (the slope of the cummulative Full GC line), changes near midnight.   plot(clipped.g1gc.z[,c("AfterSize","RealTime","FullCount")], xlab="Time of Day", col=c("#1b9e77","red","#1b9e77")) GC Analysis of heap recovered Each GC trace includes the amount of heap space in use before and after the individual GC event. During garbage coolection, unreferenced objects are identified, the space holding the unreferenced objects is freed, and thus, the difference in before and after usage indicates how much space has been freed. The following box plot and bar chart both demonstrate the same point - the amount of heap space freed per garbage colloection is surprisingly low. par(mfrow=c(2,1)) boxplot(as.vector(clipped.g1gc.z$Delta), main="Amount of Heap Recovered per GC Pass", xlab="Size in KB", horizontal = TRUE, col="red") hist(as.vector(clipped.g1gc.z$Delta), main="Amount of Heap Recovered per GC Pass", xlab="Size in KB", breaks=100, col="red") box(which = "outer", lty = "solid") This graph is the most interesting. The dark blue area shows how much heap is occupied by referenced Java objects. This represents memory that holds live data. The red fringe at the top shows how much data was recovered after each garbage collection. barplot(clipped.g1gc.z[,c("AfterSize","Delta")], col=c("#7570b3","#e7298a"), xlab="Time of Day", border=NA) legend("topleft", c("Live Objects","Heap Recovered on GC"), fill=c("#7570b3","#e7298a")) box(which = "outer", lty = "solid") When I discuss the data in the log files with the customer, I will ask for an explaination for the large amount of referenced data resident in the Java heap. There are two are posibilities: There is a memory leak and the amount of space required to hold referenced objects will continue to grow, limited only by the maximum heap size. After the maximum heap size is reached, the JVM will throw an “Out of Memory” exception every time that the application tries to allocate a new object. If this is the case, the aplication needs to be debugged to identify why old objects are referenced when they are no longer needed. The application has a legitimate requirement to keep a large amount of data in memory. The customer may want to further increase the maximum heap size. Another possible solution would be to partition the application across multiple cluster nodes, where each node has responsibility for managing a unique subset of the data. Conclusion In conclusion, R is a very powerful tool for the analysis of Java garbage collection log files. The primary difficulty is data cleansing so that information can be read into an R data frame. Once the data has been read into R, a rich set of tools may be used for thorough evaluation.

  Read the article

< Previous Page | 82 83 84 85 86 87 88 89 90 91 92 93  | Next Page >