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  • Two imageViews vs one imageView and a canvas

    - by user3009842
    I have a bitmap and I want to scale it up to fill an ImageView and overlay the unscaled version of the bitmap on top. Which would be cheaper (in terms of memory and processor usage)? Using two ImageViews, one for each version of the bitmap Using a canvas and drawing on the singular bitmap, using one ImageView I saw this question about ImageView vs Canvas, but it doesn't address memory/processor concerns. My intuition says two ImageViews may use more RAM, while using a canvas would use more processing power while the drawing occurs.

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  • Porting 32 bit C++ code to 64 bit - is it worth it? Why?

    - by NTDLS
    I am aware of some the obvious gains of the x64 architecture (higher addressable RAM addresses, ect)... but: What if my program has no real need to run in native 64 bit mode. Should I port it anyway? Are there any foreseeable deadlines for ending 32 bit support? Would my application run faster / better / more secure as native x64 code?

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  • How to copy a ram_base file to disk efficiently

    - by Hui Jin
    I want to copy a large a ram-based file (located at /dev/shm direcotry) to local disk, is there some way for an efficient copy instead of read char one by one or create another piece memory? I can use only C language here. Is there anyway that I can put the memory file directly to disk? Thanks!

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  • Returning the size of available virtual memory at run-time in C++

    - by Greenhouse Gases
    In C++ is there a predefined library function that will return the size of RAM currently available on a computer a program is being run on, at run-time? For instance, if an object is 4bytes, then can we divide the available virtual memory by 4 bytes to give an estimate of how many more objects could be stored by the program safely? I have used the sizeof() function to return the size of objects within my program. Thanks

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  • Processing large (over 1 Gig) files in PHP using stream_filter_*

    - by mike
    $fp_src=fopen('file','r'); $filter = stream_filter_prepend($fp_src, 'convert.iconv.ISO-8859-1/UTF-8'); while(fread($fp_src,4096)){ ++$count; if($count%1000==0) print ftell($fp_src)."\n"; } When I run this the script ends up consuming ~ 200 MB of RAM after going through just 35MB of the file. Running it without the stream_filter zips right through with a constant memory footprint of ~10 MB. What gives?

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  • Writing a script with the cmd prompt.

    - by Josh
    I'm trying to make a script that will place a list (in a .csv file) of processes that are running that take up more than 10 mb of RAM and shows the time + date the script was run. My teacher did this during his lecture but I can't remember how he did it. Just trying to figure out how to be better at IT. So my question is, can anyone help me with this? I don't even know where to start.

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  • Is Appfogs pricing model sustainable?

    - by Kyle Finley
    I was looking at AppFog's Pricing and they appear to be giving 2GB of ram away for free, to nonpaying customers. This seems unprecedented for PAAS provodes--providers like Heroku and App Engine remove the app from memory if it has been inactive for certain amount of time. Does cloudfoundry work similarly? Am I wrong in assuming that in a few years appfog servers will be filled with inactive non paying applications?

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  • mySQL: How many rows in a table before performance is affected?

    - by Industrial
    Hi everybody, Is there a "known limit" for columns & rows in a mySQL table that when passed, it can be safe to say that performance is severely affected? I've think that I had heard that there is a "golden number" that you really dont want to exceed in either columns or rows in a table. - Or is it all about the size of the index and available RAM + CPU on the server? Thanks!

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  • Is an Object the smallest pageable unit in the Heap?

    - by DonnieKun
    Hi, If I have a 2 GB ram and I have an 2 instances of an Object which is 1.5 GB each, the operating system will help and context switch the pages to and from harddisk. What if I have 1 instances but is 3 GB. Can the same paging method breakdown this instances into 2 pages? Or will I encounter out-of-memory issue? Thanks.

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  • Useful software for netbook?

    - by Moayad Mardini
    I'm looking for recommendations of good software that are particularly useful for netbooks. Software that run great on small screens and low CPU/RAM requirments. I'll start off with the following : Operating Systems: Ubuntu Netbook Remix. Easy Peasy: A fork of Ubuntu Netbook Remix that was once called UBuntu EEE. It isn't just for eeePCs though. Definitely worth a look if vanilla Netbook Remix isn't cutting it. (MarkM) Damn Small Linux (Source) Windows 7: With trimming the installation or compressing the Windows directory to fit on an 8GB SSD. (Will Eddins) nLite: A utility to install a lightweight version of Windows XP without the unnecessary components (like Media Player, Internet Explorer, Outlook Express, MSN Explorer, Messenger...). Utilites: TouchFreeze: To disable the touch pad while typing (Source) InSSIDer: Not only does it make it easier to find and keep a wireless connection, but it turns a netbook into the perfect mobile tool for troubleshooting wireless networks. (phenry) AltMove: Adds more functionality to your mouse for interacting with windows. (Rob) ASUS Font Resizer Utility and other tools by ASUS, specific to ASUS Eee PC series. Internet: Run FileZilla FTP client for a small screen : You can hide a lot of FileZilla's interface parts in the View menu, even the directory trees. Go into Settings = Interface and move the message log next to the transfer queue, if you haven't hidden them both or you want to see them. Select a theme with 16x16 icons. (Source) IDEs and Text Editors: Best lightweight IDE/Text Editor: A question on Stack Overflow that has many good suggestions of IDEs and general text editors for programmers. What’s a good linux C/C++ IDE for a low-res screen?: IDEs for Linux-powered netbooks. Online tools: Dropbox: Since the Netbook has limited disk space, you would like to use Cloud Apps like Dropbox and Ubuntu One so that you don't run out of space especially if you are on a holiday. Later when you go back to your desktop with big hard disk,you can take out the files from your dropbox repo. (Manish Sinha) Google products: like Docs, Calendar and Reader (aviraldg) Web sites and software lists: Netbookfiles.com: Netbook specific software downloads. Software Apps to Maximise your Netbook Battery Power: Netbooks are known for their portability. Not only are they small and lightweight but with their increased power efficiency, batteries can last much longer than conventional laptops. This also means you no longer have to carry a power adapter with you! Several brands emphasis the longevity of the battery as a strong selling point, and for those people who travel a lot, it sure is. Free Must-Have Netbook Apps: Finding software for netbooks can present challenges due to limited hard drive space, processor power, RAM, and screen real-estate. That doesn't mean you have to do without essential programs. The apps below cover all the bases -- entertainment, productivity, security, and communication -- without compromising on performance or usability. Best of all, they're free! Useful Netbook Software: With short battery lives and small resolution screens Netbooks, unlike many other computers on the market, could so with some specific software for their use. Now, not all of those I’ve found are specifically designed for Netbooks, but all are relevant. And they’re designed for Windows XP. The question is community wiki, so feel free to edit it. Updated, thank you all for suggestions.

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  • Why do GPUs overheat?

    - by JAD
    About a year ago, I added a 9800GT (1 GB version) and a Corsair CX500 PSU to an HP M8000N computer. A few weeks ago, the HDD overheated and I decided to transfer the GPU & PSU to a new build, which consists of: i3 @ 3.3Ghz Gigabyte H61 Micro ATX Mobo 4GB RAM 500GB WD HDD DVD RW Drive Cooler Master Elite 430 Tower Once I had Win7 up and running, I installed all the essential drivers that came with the Gigabyte Mobo CD. However, whenever I tried installing the Graphics Media Accelerator driver, the computer would crash and enter an endless boot sequence on the next startup. I skipped installing this driver and installed the CD driver for the 9800GT, which by now is a year old. Everything was working fine, WEI rated my GPU at 6.6 graphics & aero performance. However, after updating my Nvidia drivers to the latest, the WEI dropped my rating to 3.3 for Aero, and 4.7 for graphics performance. Just to make sure that everything was ok, I ran Bad Company 2 on medium settings. The first few minutes ran just fine at a smooth framerate, so I dismissed this as Windows being Windows. About 6 hours later, I ran BC2 again. This time I averaged anywhere from 2-5 FPS. I checked the GPU temperature through GPU-Z, and it came back as 120C. The problem with this, is that the computer was on for six hours up to that point. Wouldn't the card have experienced a reactor core meltdown a lot sooner than that? Granted, the computer was "sleeping" some of the time, but still... The next day I took out a temperature gun and ran some tests. I would point the laser at a very specific area on the reverse side of the card (not the fan or "front"), and compare the temp reading with GPU-Z. After leaving the system on idle on idle for a few minutes, I ran BC2 twice. Here are the results: GPU-Z Reading / Temp Gun Reading / Time Null / 22.3°C / Comp is Off 53°C / 33.5°C / 1:49 78°C / 46°C / 1:53 - (First BC2 run; good framerate) 102°C / 64.6°C / 2:01 - (System is again on idle) 113°C / 64.8°C / 2:10 119°C / 71.8°C / 2:17 - (Second BC2 run; poor framerate) I should also mention that I also took a temp recording of another part of the GPU from 2:01-2:17. The temp in this area jumped from 75°C to 82.9°C in that time frame. This pretty much confirms that GPU-Z is reporting the temperature accurately, and the card is overheating. But I'd like to know why; the cars is doing nothing and still the temperature climbs at a steady rate. I thoroughly cleaned the GPU and PSU when I salvaged them from the old HP M8000N computer with a can of compressed air, dust cant be the issue. Similarly, the rest of the computer is brand new. I installed various Nvidia drivers, but no luck. It seems strange to me that a year-old card is suddenly failing on me; aren't they supposed to last at least two years? Could this be a driver issue? Is the motherboard faulty? Could the PSU be overfeeding the card on voltage? Neither case seems likely, as the CPU, RAM and otherwise the rest of the comp has worked flawlessly and has stayed well within respectable temp ranges (the i3 lingers around 50C, the HDD stays at 30C, so does the PSU). How can I pinpoint the issue?

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  • Graphics card initialisation problems when booting - requires a "double" boot

    - by DMA57361
    Problem Outline When booting from cold (and my machine is disconnected from main power when off, but leaving it connected doesn't help) the graphics card (single PCI-e card GeForce 460) will not initialise on the first boot, leaving me with the motherboards on-board graphics (which kick in automatically if no PCI-e card is found). However, if I restart the computer - normally I do this by powering it off just after the numlock lights up on the keyboard (ie, just after POST/BIOS and before Windows takes over), wait for the system to whirr down, and power up again - the graphics card will work correctly. Once double-booted in this matter the system seems to work correctly - with no noticeable problems. This is reproducible every time I try to boot - it has been working like this for about a month now. Background Information Sept 2010 - I suffered a hardware malfunction (crashes in Windows and graphics corruption on BIOS screens). By way of spare hardware I determined that replacing the PSU removed the issue, so I replaced the PSU with a brand new one of slightly higher power (460W replaced with 500W). Oct 2010 - The problem resurfaced. I purchased a new graphics card (GeForce 460), which removed the problem. The new graphics card immediately started having the boot initialisation problems mentioned. I presumed there was a motherboard fault all along, but because the system worked once booted, and I was temporarily out of spare money, I left the system alone and continued to use it. Early/Mid Dec 2010 - In the space of 5 days I recieved 3 instances of hard drive corruption (seemlingly fixed by chkdsk and sfc in each case...). Since I was already under the impression the motherboard was faulty, I purchased a new one ASAP, this also required new RAM (as I dropped from 4 slots to 2 and didn't want to drop mem quantity). Past 3-4 weeks - With a brand new PSU, Graphics Card, Motherboard and RAM I'm suffering the problem outlined above. So, what could be causing this and how do I can resolve it? Additional Notes Once double-booted the system seems to work entirely correctly. The graphics card problem has occured on two entirely different motherboards. I do not have the opportunity to test the graphics card in a different computer (I've only the old motherboard, which is dubious, or a really old desktop that still has an AGP port). Under load (ie, modern games for long enough for temperatures to plateau) the system remains stable and performs as expected. The software that came with the new motherboard and SpeenFan both report all voltages and temperatures are within nominal bounds, when idle and when under load. I've looking over the BIOS settings for my motherboard multiple times and can find nothing that helps. This system is configured to run with everything at standard levels - no overclocking. I've tried booting the system with only the mobo and graphics card connected (thinking maybe my new PSU was too weak for the new gfx card, even though it meets the quoted PSU requirements for the card) but the same problem persists (and really if the PSU was weak I'd have problems with the system under load). When the gfx card does not initialise the fan on its cooling unit is running, possibly slower than otherwise - but this measurement is by eye and so unreliable.

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  • Diagnosing Solaris 8 server memory and swap space usage

    - by datSilencer
    Hello everyone. Essentially, my question is related to memory allocation for Solaris virtual machines. I am running a couple of old Sun ONE 6 Java web servers on two Solaris 8 virtual machines. I see that there's a reasonable amount of swap space being used, but I'm not exactly sure if this could indicate a need to add more RAM to these machines. At service peak hours (mornings usually), the response time of the web application these servers host jumps up to at most 11 seconds (somewhat detrimental for a relatively simple web page loading action). Average response time at non peak times is about 5 seconds. What would you be able to infer about the RAM usage for these machines from the ouput below? Is this information reasonably sufficient? Or would I need to run some other commands to rule out server memory starvation? Finally, since there is a Java application at the core of the setup, I've also thought about: 1) Trace the heap's Object allocation to detect potential memory leaks. 2) Do some performance profiling to see if this instead related to networking delays. I mention this since the application talks with a single Oracle Database, but I would doubt this to be the case since they're pretty close from a network segmentation perspective. I appreciate any kind of insight and feedback you could provide. Thanks for your time and help. Server 1: 40 processes: 38 sleeping, 1 zombie, 1 on cpu CPU states: 99.1% idle, 0.4% user, 0.4% kernel, 0.0% iowait, 0.0% swap Memory: 2048M real, 295M free, 865M swap in use, 3788M swap free PID USERNAME THR PRI NICE SIZE RES STATE TIME CPU COMMAND 12676 webservd 112 29 10 616M 242M sleep 103:37 0.48% webservd 18317 root 1 59 0 23M 19M sleep 67:24 0.08% perl 9479 support 1 59 0 6696K 2448K cpu/1 0:11 0.05% top 8012 root 10 59 0 34M 704K sleep 80:54 0.04% java 1881 root 33 29 10 110M 13M sleep 33:03 0.02% webservd 7808 root 1 59 0 83M 67M sleep 7:59 0.00% perl 1461 root 20 59 0 5328K 1392K sleep 6:49 0.00% syslogd 1691 root 2 59 0 27M 680K sleep 4:22 0.00% webservd 24386 root 1 59 0 15M 11M sleep 2:50 0.00% perl 23259 root 1 59 0 11M 4240K sleep 2:42 0.00% perl 24718 root 1 59 0 11M 5464K sleep 2:29 0.00% perl 22810 root 1 59 0 19M 11M sleep 2:21 0.00% perl 24451 root 1 53 2 11M 3800K sleep 2:18 0.00% perl 18501 root 1 56 1 11M 3960K sleep 2:18 0.00% perl 14450 root 1 56 1 15M 6920K sleep 1:49 0.00% perl Server 2 42 processes: 40 sleeping, 1 zombie, 1 on cpu CPU states: 98.8% idle, 0.4% user, 0.8% kernel, 0.0% iowait, 0.0% swap Memory: 1024M real, 31M free, 554M swap in use, 3696M swap free PID USERNAME THR PRI NICE SIZE RES STATE TIME CPU COMMAND 5607 webservd 74 29 10 284M 173M sleep 20:14 0.21% webservd 15919 support 1 59 0 4056K 2520K cpu/1 0:08 0.09% top 13138 root 10 59 0 34M 1952K sleep 210:51 0.08% java 13753 root 1 59 0 22M 12M sleep 170:15 0.07% perl 22979 root 33 29 10 112M 7864K sleep 85:07 0.04% webservd 22930 root 1 59 0 3424K 1552K sleep 17:47 0.01% xntpd 22978 root 2 59 0 27M 2296K sleep 10:49 0.00% webservd 13571 root 1 59 0 9400K 5112K sleep 5:52 0.00% perl 5606 root 2 29 10 29M 9056K sleep 0:36 0.00% webservd 15910 support 1 59 0 9128K 2616K sleep 0:00 0.00% sshd 13106 root 1 59 0 82M 3520K sleep 7:47 0.00% perl 13547 root 1 59 0 12M 5528K sleep 6:38 0.00% perl 13518 root 1 59 0 9336K 3792K sleep 6:24 0.00% perl 13399 root 1 56 1 8072K 3616K sleep 5:18 0.00% perl 13557 root 1 53 2 8248K 3624K sleep 5:12 0.00% perl

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  • AMD 24 core server memory bandwidth

    - by ntherning
    I need some help to determine whether the memory bandwidth I'm seeing under Linux on my server is normal or not. Here's the server spec: HP ProLiant DL165 G7 2x AMD Opteron 6164 HE 12-Core 40 GB RAM (10 x 4GB DDR1333) Debian 6.0 Using mbw on this server I get the following numbers: foo1:~# mbw -n 3 1024 Long uses 8 bytes. Allocating 2*134217728 elements = 2147483648 bytes of memory. Using 262144 bytes as blocks for memcpy block copy test. Getting down to business... Doing 3 runs per test. 0 Method: MEMCPY Elapsed: 0.58047 MiB: 1024.00000 Copy: 1764.082 MiB/s 1 Method: MEMCPY Elapsed: 0.58012 MiB: 1024.00000 Copy: 1765.152 MiB/s 2 Method: MEMCPY Elapsed: 0.58010 MiB: 1024.00000 Copy: 1765.201 MiB/s AVG Method: MEMCPY Elapsed: 0.58023 MiB: 1024.00000 Copy: 1764.811 MiB/s 0 Method: DUMB Elapsed: 0.36174 MiB: 1024.00000 Copy: 2830.778 MiB/s 1 Method: DUMB Elapsed: 0.35869 MiB: 1024.00000 Copy: 2854.817 MiB/s 2 Method: DUMB Elapsed: 0.35848 MiB: 1024.00000 Copy: 2856.481 MiB/s AVG Method: DUMB Elapsed: 0.35964 MiB: 1024.00000 Copy: 2847.310 MiB/s 0 Method: MCBLOCK Elapsed: 0.23546 MiB: 1024.00000 Copy: 4348.860 MiB/s 1 Method: MCBLOCK Elapsed: 0.23544 MiB: 1024.00000 Copy: 4349.230 MiB/s 2 Method: MCBLOCK Elapsed: 0.23544 MiB: 1024.00000 Copy: 4349.359 MiB/s AVG Method: MCBLOCK Elapsed: 0.23545 MiB: 1024.00000 Copy: 4349.149 MiB/s On one of my other servers (based on Intel Xeon E3-1270): foo2:~# mbw -n 3 1024 Long uses 8 bytes. Allocating 2*134217728 elements = 2147483648 bytes of memory. Using 262144 bytes as blocks for memcpy block copy test. Getting down to business... Doing 3 runs per test. 0 Method: MEMCPY Elapsed: 0.18960 MiB: 1024.00000 Copy: 5400.901 MiB/s 1 Method: MEMCPY Elapsed: 0.18922 MiB: 1024.00000 Copy: 5411.690 MiB/s 2 Method: MEMCPY Elapsed: 0.18944 MiB: 1024.00000 Copy: 5405.491 MiB/s AVG Method: MEMCPY Elapsed: 0.18942 MiB: 1024.00000 Copy: 5406.024 MiB/s 0 Method: DUMB Elapsed: 0.14838 MiB: 1024.00000 Copy: 6901.200 MiB/s 1 Method: DUMB Elapsed: 0.14818 MiB: 1024.00000 Copy: 6910.561 MiB/s 2 Method: DUMB Elapsed: 0.14820 MiB: 1024.00000 Copy: 6909.628 MiB/s AVG Method: DUMB Elapsed: 0.14825 MiB: 1024.00000 Copy: 6907.127 MiB/s 0 Method: MCBLOCK Elapsed: 0.04362 MiB: 1024.00000 Copy: 23477.623 MiB/s 1 Method: MCBLOCK Elapsed: 0.04262 MiB: 1024.00000 Copy: 24025.151 MiB/s 2 Method: MCBLOCK Elapsed: 0.04258 MiB: 1024.00000 Copy: 24048.849 MiB/s AVG Method: MCBLOCK Elapsed: 0.04294 MiB: 1024.00000 Copy: 23847.599 MiB/s For reference here's what I get on my Intel based laptop: laptop:~$ mbw -n 3 1024 Long uses 8 bytes. Allocating 2*134217728 elements = 2147483648 bytes of memory. Using 262144 bytes as blocks for memcpy block copy test. Getting down to business... Doing 3 runs per test. 0 Method: MEMCPY Elapsed: 0.40566 MiB: 1024.00000 Copy: 2524.269 MiB/s 1 Method: MEMCPY Elapsed: 0.38458 MiB: 1024.00000 Copy: 2662.638 MiB/s 2 Method: MEMCPY Elapsed: 0.38876 MiB: 1024.00000 Copy: 2634.043 MiB/s AVG Method: MEMCPY Elapsed: 0.39300 MiB: 1024.00000 Copy: 2605.600 MiB/s 0 Method: DUMB Elapsed: 0.30707 MiB: 1024.00000 Copy: 3334.745 MiB/s 1 Method: DUMB Elapsed: 0.30425 MiB: 1024.00000 Copy: 3365.653 MiB/s 2 Method: DUMB Elapsed: 0.30342 MiB: 1024.00000 Copy: 3374.849 MiB/s AVG Method: DUMB Elapsed: 0.30491 MiB: 1024.00000 Copy: 3358.328 MiB/s 0 Method: MCBLOCK Elapsed: 0.07875 MiB: 1024.00000 Copy: 13003.670 MiB/s 1 Method: MCBLOCK Elapsed: 0.08374 MiB: 1024.00000 Copy: 12228.034 MiB/s 2 Method: MCBLOCK Elapsed: 0.07635 MiB: 1024.00000 Copy: 13411.216 MiB/s AVG Method: MCBLOCK Elapsed: 0.07961 MiB: 1024.00000 Copy: 12862.006 MiB/s So according to mbw my laptop is 3 times faster than the server!!! Please help me explain this. I've also tried to mount a ram disk and use dd to benchmark it and I get similar differences so I don't think mbw is to blame. I've checked the BIOS settings and the memory seem to be running at full speed. According to the hosting company the modules are all OK. Could this have something to do with NUMA? It seems like Node Interleaving is disabled on this server. Will enabling it (thus turning off NUMA) make a difference? foo1:~# numactl --hardware available: 4 nodes (0-3) node 0 cpus: 0 1 2 3 4 5 node 0 size: 8190 MB node 0 free: 7898 MB node 1 cpus: 6 7 8 9 10 11 node 1 size: 12288 MB node 1 free: 12073 MB node 2 cpus: 18 19 20 21 22 23 node 2 size: 12288 MB node 2 free: 12034 MB node 3 cpus: 12 13 14 15 16 17 node 3 size: 8192 MB node 3 free: 8032 MB node distances: node 0 1 2 3 0: 10 20 20 20 1: 20 10 20 20 2: 20 20 10 20 3: 20 20 20 10

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  • GNU/Linux swapping blocks system

    - by Ole Tange
    I have used GNU/Linux on systems from 4 MB RAM to 512 GB RAM. When they start swapping, most of the time you can still log in and kill off the offending process - you just have to be 100-1000 times more patient. On my new 32 GB system that has changed: It blocks when it starts swapping. Sometimes with full disk activity but other times with no disk activity. To examine what might be the issue I have written this program. The idea is: 1 grab 3% of the memory free right now 2 if that caused swap to increase: stop 3 keep the chunk used for 30 seconds by forking off 4 goto 1 - #!/usr/bin/perl sub freekb { my $free = `free|grep buffers/cache`; my @a=split / +/,$free; return $a[3]; } sub swapkb { my $swap = `free|grep Swap:`; my @a=split / +/,$swap; return $a[2]; } my $swap = swapkb(); my $lastswap = $swap; my $free; while($lastswap >= $swap) { print "$swap $free"; $lastswap = $swap; $swap = swapkb(); $free = freekb(); my $used_mem = "x"x(1024 * $free * 0.03); if(not fork()) { sleep 30; exit(); } } print "Swap increased $swap $lastswap\n"; Running the program forever ought to keep the system at the limit of swapping, but only grabbing a minimal amount of swap and do that very slowly (i.e. a few MB at a time at most). If I run: forever free | stdbuf -o0 timestamp > freelog I ought to see swap slowly rising every second. (forever and timestamp from https://github.com/ole-tange/tangetools). But that is not the behaviour I see: I see swap increasing in jumps and that the system is completely blocked during these jumps. Here the system is blocked for 30 seconds with the swap usage increases with 1 GB: secs 169.527 Swap: 18440184 154184 18286000 170.531 Swap: 18440184 154184 18286000 200.630 Swap: 18440184 1134240 17305944 210.259 Swap: 18440184 1076228 17363956 Blocked: 21 secs. Swap increase 2400 MB: 307.773 Swap: 18440184 581324 17858860 308.799 Swap: 18440184 597676 17842508 330.103 Swap: 18440184 2503020 15937164 331.106 Swap: 18440184 2502936 15937248 Blocked: 20 secs. Swap increase 2200 MB: 751.283 Swap: 18440184 885288 17554896 752.286 Swap: 18440184 911676 17528508 772.331 Swap: 18440184 3193532 15246652 773.333 Swap: 18440184 1404540 17035644 Blocked: 37 secs. Swap increase 2400 MB: 904.068 Swap: 18440184 613108 17827076 905.072 Swap: 18440184 610368 17829816 942.424 Swap: 18440184 3014668 15425516 942.610 Swap: 18440184 2073580 16366604 This is bad enough, but what is even worse is that the system sometimes stops responding at all - even if I wait for hours. I have the feeling it is related to the swapping issue, but I cannot tell for sure. My first idea was to tweak /proc/sys/vm/swappiness from 60 to 0 or 100, just to see if that had any effect at all. 0 did not have an effect, but 100 did cause the problem to arise less often. How can I prevent the system from blocking for such a long time? Why does it decide to swapout 1-3 GB when less than 10 MB would suffice?

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  • Linux not buffering block I/O when the device is not "in use" (i.e. mounted)

    - by Radek Hladík
    I am installing new server and I've found an interesting issue. The server is running Fedora 19 (3.11.7-200.fc19.x86_64 kernel) and is supposed to host a few KVM/Qemu virtual servers (mail server, file server, etc..). The HW is Intel(R) Xeon(R) CPU 5160 @ 3.00GHz with 16GB RAM. One of the most important features will be Samba server and we have decided to make it as virtual machine with almost direct access to the disks. So the real HDD is cached on SSD (via bcache) then raided with md and the final device is exported into the virtual machine via virtio. The virtual machine is again Fedora 19 with the same kernel. One important topic to find out is whether the virtualization layer will not introduce high overload into disk I/Os. So far I've been able to get up to 180MB/s in VM and up to 220MB/s on real HW (on the SSD disk). I am still not sure why the overhead is so big but it is more than the network can handle so I do not care so much. The interesting thing is that I've found that the disk reads are not buffered in the VM unless I create and mount FS on the disk or I use the disks somehow. Simply put: Lets do dd to read disk for the first time (the /dev/vdd is an old Raptor disk 70MB/s is its real speed): [root@localhost ~]# dd if=/dev/vdd of=/dev/null bs=256k count=10000 ; cat /proc/meminfo | grep Buffers 2621440000 bytes (2.6 GB) copied, 36.8038 s, 71.2 MB/s Buffers: 14444 kB Rereading the data shows that they are cached somewhere but not in buffers of the VM. Also the speed increased to "only" 500MB/s. The VM has 4GB of RAM (more that the test file) [root@localhost ~]# dd if=/dev/vdd of=/dev/null bs=256k count=10000 ; cat /proc/meminfo | grep Buffers 2621440000 bytes (2.6 GB) copied, 5.16016 s, 508 MB/s Buffers: 14444 kB [root@localhost ~]# dd if=/dev/vdd of=/dev/null bs=256k count=10000 ; cat /proc/meminfo | grep Buffers 2621440000 bytes (2.6 GB) copied, 5.05727 s, 518 MB/s Buffers: 14444 kB Now lets mount the FS on /dev/vdd and try the dd again: [root@localhost ~]# mount /dev/vdd /mnt/tmp [root@localhost ~]# dd if=/dev/vdd of=/dev/null bs=256k count=10000 ; cat /proc/meminfo | grep Buffers 2621440000 bytes (2.6 GB) copied, 4.68578 s, 559 MB/s Buffers: 2574592 kB [root@localhost ~]# dd if=/dev/vdd of=/dev/null bs=256k count=10000 ; cat /proc/meminfo | grep Buffers 2621440000 bytes (2.6 GB) copied, 1.50504 s, 1.7 GB/s Buffers: 2574592 kB While the first read was the same, all 2.6GB got buffered and the next read was at 1.7GB/s. And when I unmount the device: [root@localhost ~]# umount /mnt/tmp [root@localhost ~]# cat /proc/meminfo | grep Buffers Buffers: 14452 kB [root@localhost ~]# dd if=/dev/vdd of=/dev/null bs=256k count=10000 ; cat /proc/meminfo | grep Buffers 2621440000 bytes (2.6 GB) copied, 5.10499 s, 514 MB/s Buffers: 14468 kB The bcache was disabled while testing and the results are same on faster (newer) HDDs and on SSD (except for the initial read speed of course). To sum it up. When I read from the device via dd first time, it gets read from the disk. Next time I reread it gets cached in the host but not in the guest (thats actually the same issue, more on that later). When I mount the filesystem but try to read the device directly it gets cached in VM (via buffers). As soon as I stop "using" it, buffers are discarded and the device is not cached anymore in the VM. When I looked into buffers value on the host I realized that the situation is the same. The block I/O gets buffered only when the disk is in use, in this case it means "exported to a VM". On host, after all the measurement done: 3165552 buffers On the host, after the VM shutdown: 119176 buffers I know it is not important as the disks will be mounted all the time but I am curious and I would like to know why it is working like this.

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  • Is Apache 2.2.22 able to sustain 1.000 simultaneous connected clients?

    - by Fnux
    For an article in a news paper, I'm benchmarking 5 different web servers (Apache2, Cherokee, Lighttpd, Monkey and Nginx). The tests made consist of measuring the execution times as well as different parameters such as the number of request served per second, the amount of RAM, the CPU used, during a growing load of simultaneous clients (from 1 to 1.000 with a step of 10) each client sending 1.000.000 requets of a small fixed file, then of a medium fixed file, then a small dynamic content (hello.php) and finally a complex dynamic content (the computation of the reimbursment of a loan). All the web servers are able to sustain such a load (up to 1.000 clients) but Apache2 which always stops to respond when the test reach 450 to 500 simultaneous clients. My configuration is : CPU: AMD FX 8150 8 cores @ 4.2 GHz RAM: 32 Gb. SSD: 2 x Crucial 240 Gb SATA6 OS: Ubuntu 12.04.3 64 bit WS: Apache 2.2.22 My Apache2 configuration is as follows: /etc/apache2/apache2.conf LockFile ${APACHE_LOCK_DIR}/accept.lock PidFile ${APACHE_PID_FILE} Timeout 30 KeepAlive On MaxKeepAliveRequests 1000000 KeepAliveTimeout 2 ServerName "fnux.net" <IfModule mpm_prefork_module> StartServers 16 MinSpareServers 16 MaxSpareServers 16 ServerLimit 2048 MaxClients 1024 MaxRequestsPerChild 0 </IfModule> User ${APACHE_RUN_USER} Group ${APACHE_RUN_GROUP} AccessFileName .htaccess <Files ~ "^\.ht"> Order allow,deny Deny from all Satisfy all </Files> DefaultType None HostnameLookups Off ErrorLog ${APACHE_LOG_DIR}/error.log LogLevel emerg Include mods-enabled/*.load Include mods-enabled/*.conf Include httpd.conf Include ports.conf LogFormat "%v:%p %h %l %u %t \"%r\" %>s %O \"%{Referer}i\" \"%{User-Agent}i\"" vhost_combined LogFormat "%h %l %u %t \"%r\" %>s %O \"%{Referer}i\" \"%{User-Agent}i\"" combined LogFormat "%h %l %u %t \"%r\" %>s %O" common LogFormat "%{Referer}i -> %U" referer LogFormat "%{User-agent}i" agent Include conf.d/ Include sites-enabled/ /etc/apache2/ports.conf NameVirtualHost *:8180 Listen 8180 <IfModule mod_ssl.c> Listen 443 </IfModule> <IfModule mod_gnutls.c> Listen 443 </IfModule> /etc/apache2/mods-available <IfModule mod_fastcgi.c> AddHandler php5-fcgi .php Action php5-fcgi /cgi-bin/php5.external <Location "/cgi-bin/php5.external"> Order Deny,Allow Deny from All Allow from env=REDIRECT_STATUS </Location> </IfModule> /etc/apache2/sites-available/default <VirtualHost *:8180> ServerAdmin webmaster@localhost DocumentRoot /var/www/apache2 <Directory /> Options FollowSymLinks AllowOverride None </Directory> <Directory /var/www/> Options Indexes FollowSymLinks MultiViews AllowOverride None Order allow,deny allow from all </Directory> ScriptAlias /cgi-bin/ /usr/lib/cgi-bin/ <Directory "/usr/lib/cgi-bin"> AllowOverride None Options +ExecCGI -MultiViews +SymLinksIfOwnerMatch Order allow,deny Allow from all </Directory> ErrorLog ${APACHE_LOG_DIR}/error.log LogLevel emerg ##### CustomLog ${APACHE_LOG_DIR}/access.log combined Alias /doc/ "/usr/share/doc/" <Directory "/usr/share/doc/"> Options Indexes MultiViews FollowSymLinks AllowOverride None Order deny,allow Deny from all Allow from 127.0.0.0/255.0.0.0 ::1/128 </Directory> <IfModule mod_fastcgi.c> AddHandler php5-fcgi .php Action php5-fcgi /php5-fcgi Alias /php5-fcgi /usr/lib/cgi-bin/php5-fcgi FastCgiExternalServer /usr/lib/cgi-bin/php5-fcgi -host 127.0.0.1:9000 -pass-header Authorization </IfModule> </VirtualHost> /etc/security/limits.conf * soft nofile 1000000 * hard nofile 1000000 So, I would trully appreciate your advice to setup Apache2 to make it able to sustain 1.000 simultaneous clients, if this is even possible. TIA for your help. Cheers.

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  • Performance issues when using SSD for a developer notebook (WAMP/LAMP stack)?

    - by András Szepesházi
    I'm a web application developer using my notebook as a standalone development environment (WAMP stack). I just switched from a Core2-duo Vista 32 bit notebook with 2Gb RAM and SATA HDD, to an i5-2520M Win7 64 bit with 4Gb RAM and 128 GB SDD (Corsair P3 128). My initial experience was what I expected, fast boot, quick load of all the applications (Eclipse takes now 5 seconds as opposed to 30s on my old notebook), overall great experience. Then I started to build up my development stack, both as LAMP (using VirtualBox with a debian guest) and WAMP (windows native apache + mysql + php). I wanted to compare those two. This still all worked great out, then I started to pull in my projects to these stacks. And here came the nasty surprise, one of those projects produced a lot worse response times than on my old notebook (that was true for both the VirtualBox and WAMP stack). Apache, php and mysql configurations were practically identical in all environments. I started to do a lot of benchmarking and profiling, and here is what I've found: All general benchmarks (Performance Test 7.0, HDTune Pro, wPrime2 and some more) gave a big advantage to the new notebook. Nothing surprising here. Disc specific tests showed that read/write operations peaked around 380M/160M for the SSD, and all the different sized block operations also performed very well. Started apache performance benchmarking with Apache Benchmark for a small static html file (10 concurrent threads, 500 iterations). Old notebook: min 47ms, median 111ms, max 156ms New WAMP stack: min 71ms, median 135ms, max 296ms New LAMP stack (in VirtualBox): min 6ms, median 46ms, max 175ms Right here I don't get why the native WAMP stack performed so bad, but at least the LAMP environment brought the expected speed. Apache performance measurement for non-cached php content. The php runs a loop of 1000 and generates sha1(uniqid()) inisde. Again, 10 concurrent threads, 500 iterations were used for the benchmark. Old notebook: min 0ms, median 39ms, max 218ms New WAMP stack: min 20ms, median 61ms, max 186ms New LAMP stack (in VirtualBox): min 124ms, median 704ms, max 2463ms What the hell? The new LAMP performed miserably, and even the new native WAMP was outperformed by the old notebook. php + mysql test. The test consists of connecting to a database and reading a single record form a table using INNER JOIN on 3 more (indexed) tables, repeated 100 times within a loop. Databases were identical. 10 concurrent threads, 100 iterations were used for the benchmark. Old notebook: min 1201ms, median 1734ms, max 3728ms New WAMP stack: min 367ms, median 675ms, max 1893ms New LAMP stack (in VirtualBox): min 1410ms, median 3659ms, max 5045ms And the same test with concurrency set to 1 (instead of 10): Old notebook: min 1201ms, median 1261ms, max 1357ms New WAMP stack: min 399ms, median 483ms, max 539ms New LAMP stack (in VirtualBox): min 285ms, median 348ms, max 444ms Strictly for my purposes, as I'm using a self contained development environment (= low concurrency) I could be satisfied with the second test's result. Though I have no idea why the VirtualBox environment performed so bad with higher concurrency. Finally I performed a test of including many php files. The application that I mentioned at the beginning, the one that was performing so bad, has a heavy bootstrap, loads hundreds of small library and configuration files while initializing. So this test does nothing else just includes about 100 files. Concurrency set to 1, 100 iterations: Old notebook: min 140ms, median 168ms, max 406ms New WAMP stack: min 434ms, median 488ms, max 604ms New LAMP stack (in VirtualBox): min 413ms, median 1040ms, max 1921ms Even if I consider that VirtualBox reached those files via shared folders, and that slows things down a bit, I still don't see how could the old notebook outperform so heavily both new configurations. And I think this is the real root of the slow performance, as the application uses even more includes, and the whole bootstrap will occur several times within a page request (for each ajax call, for example). To sum it up, here I am with a brand new high-performance notebook that loads the same page in 20 seconds, that my old notebook can do in 5-7 seconds. Needless to say, I'm not a very happy person right now. Why do you think I experience these poor performance values? What are my options to remedy this situation?

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  • SmartOS reboots spontaneously

    - by Alex
    I run a SmartOS system on a Hetzner EX4S (Intel Core i7-2600, 32G RAM, 2x3Tb SATA HDD). There are six virtual machines on the host: [root@10-bf-48-7f-e7-03 ~]# vmadm list UUID TYPE RAM STATE ALIAS d2223467-bbe5-4b81-a9d1-439e9a66d43f KVM 512 running xxxx1 5f36358f-68fa-4351-b66f-830484b9a6ee KVM 1024 running xxxx2 d570e9ac-9eac-4e4f-8fda-2b1d721c8358 OS 1024 running xxxx3 ef88979e-fb7f-460c-bf56-905755e0a399 KVM 1024 running xxxx4 d8e06def-c9c9-4d17-b975-47dd4836f962 KVM 4096 running xxxx5 4b06fe88-db6e-4cf3-aadd-e1006ada7188 KVM 9216 running xxxx5 [root@10-bf-48-7f-e7-03 ~]# The host reboots several times a week with no crash dump in /var/crash and no messages in the /var/adm/messages log. Basically /var/adm/messages looks like there was a hard reset: 2012-11-23T08:54:43.210625+00:00 10-bf-48-7f-e7-03 rsyslogd: -- MARK -- 2012-11-23T09:14:43.187589+00:00 10-bf-48-7f-e7-03 rsyslogd: -- MARK -- 2012-11-23T09:34:43.165100+00:00 10-bf-48-7f-e7-03 rsyslogd: -- MARK -- 2012-11-23T09:54:43.142065+00:00 10-bf-48-7f-e7-03 rsyslogd: -- MARK -- 2012-11-23T10:14:43.119365+00:00 10-bf-48-7f-e7-03 rsyslogd: -- MARK -- 2012-11-23T10:34:43.096351+00:00 10-bf-48-7f-e7-03 rsyslogd: -- MARK -- 2012-11-23T10:54:43.073821+00:00 10-bf-48-7f-e7-03 rsyslogd: -- MARK -- 2012-11-23T10:57:55.610954+00:00 10-bf-48-7f-e7-03 genunix: [ID 540533 kern.notice] #015SunOS Release 5.11 Version joyent_20121018T224723Z 64-bit 2012-11-23T10:57:55.610962+00:00 10-bf-48-7f-e7-03 genunix: [ID 299592 kern.notice] Copyright (c) 2010-2012, Joyent Inc. All rights reserved. 2012-11-23T10:57:55.610967+00:00 10-bf-48-7f-e7-03 unix: [ID 223955 kern.info] x86_feature: lgpg 2012-11-23T10:57:55.610971+00:00 10-bf-48-7f-e7-03 unix: [ID 223955 kern.info] x86_feature: tsc 2012-11-23T10:57:55.610974+00:00 10-bf-48-7f-e7-03 unix: [ID 223955 kern.info] x86_feature: msr 2012-11-23T10:57:55.610978+00:00 10-bf-48-7f-e7-03 unix: [ID 223955 kern.info] x86_feature: mtrr 2012-11-23T10:57:55.610981+00:00 10-bf-48-7f-e7-03 unix: [ID 223955 kern.info] x86_feature: pge 2012-11-23T10:57:55.610984+00:00 10-bf-48-7f-e7-03 unix: [ID 223955 kern.info] x86_feature: de 2012-11-23T10:57:55.610987+00:00 10-bf-48-7f-e7-03 unix: [ID 223955 kern.info] x86_feature: cmov 2012-11-23T10:57:55.610995+00:00 10-bf-48-7f-e7-03 unix: [ID 223955 kern.info] x86_feature: mmx 2012-11-23T10:57:55.611000+00:00 10-bf-48-7f-e7-03 unix: [ID 223955 kern.info] x86_feature: mca 2012-11-23T10:57:55.611004+00:00 10-bf-48-7f-e7-03 unix: [ID 223955 kern.info] x86_feature: pae 2012-11-23T10:57:55.611008+00:00 10-bf-48-7f-e7-03 unix: [ID 223955 kern.info] x86_feature: cv8 The problem is that sometimes the host loses the network interface on reboot so we need to perform a manual hardware reset to bring it back. We do not have physical or virtual access to the server console - no KVM, no iLO or anything like this. So, the only way to debug is to analyze crash dumps/log files. I am not a SmartOS/Solaris expert so I am not sure how to proceed. Is there any equivalent of Linux netconsole for SmartOS? Can I just redirect the console output to the network port somehow? Maybe I am missing something obvious and crash information is located somewhere else.

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  • Wear and tear on server hard drive from filesystem polling by PHP script

    - by jackie
    So I'm working on a discussion platform, and various clients will visit http://host/thread.php, which will render the discussion thread to date in addition to a form to submit a new post. When a new post is submitted, I would like all of the other clients with browser windows open to have it appear in near-real-time. One of the constraints of my script is that it may not use a DBMS and it must stay in the filesystem. Additionally, I can't use any PECL/PEAR extensions like inotify or anything like that for IPC. The flow will look like this: Client A requests thread.php and the thread is so far empty, but nonetheless it opens a Server-Side Event at eventPusher.php. Client B does the same. Client A fills out a post in the form and and submits (POSTs) it to subHandler.php. ??? (subHandler stores the new submission into the main thread storefile which gets read from when a fresh, new client requests thread.php, in addition to somehow signalling to the continually-running eventPusher event-source that a new comment was posted and that it should echo the event-json to the client. How, exactly, it will send this signal I'm yet unsure of, but there are a few options that I've thought of -- this is the crux of the question, so see below for more clarification) eventPusher.php happily pushes the new event to the client and it shows up soon after it was originally submitted on all clients who have the page open's screens. Now for the #4 missing-link mystery-step, I see a few problems. I mean, either way, eventPusher is gonna be doing a while loop of some sort -- it's gonna be polling something, I think that much is clear. (If that's a bad assumption please do let me know.) Now, the simplest way would be subHandler gets invoked on the form submission, writes it to the main store in addition to newComments.xml, then exits without doing anything else. Then eventPusher checks in newComments.xml every X seconds (by the way, what would be a reasonable time interval here?) and if it finds something then it emits an event to the client. Now, my fear with this is that the server's hard drive will have to constantly start spinning up. Maybe this isn't the case, perhaps it would just get cached in RAM and the linux kernel would take care of this transparently such that filesystem access doesn't actually engage the device because the kernel knows that that particular file hasn't changed since last read. * idea #2: I have no idea how to go about this, but perhaps there is a variable scope that gets stored in general RAM on the system which can be read by any process. Like if we mega-exported a bash variable so that $new_post is normally false but it gets toggled to true by subHandler, and then back to flase once it's pushed to the client. I doubt there's such a variable scope in PHP directly, but I struggle with the concept of variable scope, I just can't seem to understand it no matter what I read on it. * idea #3: eventPusher queries ps in its whileloop for another instance of itself. If there's not another eventPusher active then it's highly unlikely that new comments will be getting submitted. It's okay if this only works =90% of the time, it doesn't need to be completely foolproof. * idea #4: eventPusher queries DMESG to see if that file's been written to recently. So to sum everything up, I need to have inter-php-script-communication in near-real-time that will work on a standard mod_php shared hosting setup without any elevated privileges, PHP addon modules, or other system adjustments that can't be done from the PHP script itself at runtime. With*out* spinning up the drive more than a few times. No SQL servers either. Apologies if my english isn't the best, I'm still trying to improve on it.

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  • Asus P8P67 Rev. 3.1 Motherboard issues powering on and saving settings

    - by Scott
    Edit: New Information Have some updated information from the old question below: So basically my issue right now is somewhat similar, but I've been able to rule out a couple of things. I don't think this has anything to do with light on the motherboard. No matter what lights are on/off on the motherboard when the computer is off, they don't affect this issue. The main power LED on the Mobo is always lit when the power supply is turned on, and that's what matters anyway. Even when the main power LED is on, the PC will NOT boot up the first time I hit the power switch. I have to go reset the power supply (make all lights turn off on the Mobo and back on), and THEN hit the power switch. Then everything boots up. Also, the BIOS settings are reset every time this happens. Asus Tech Support told me to try jumping the power with something metal to try and rule out that it's a problem with the connectors getting power, or if it's a problem with the case power switch pins - haven't done that yet though. Any ideas? This is a lot simpler than it was before when I thought it had to do with certain LED indicators for RAM, EPU, etc. Original Question So I built my new desktop just about 3 weeks ago. I've been having a few issues which I think are all related to my motherboard, an Asus P8P67 Revision 3.1, but I'm not 100% sure as this is really the first from-scratch build I've ever done. I've posted these questions on the Asus forums, Asus Tech Support, and the Corsair forums as well as I thought it might have something to do with my power supply at one point. None of these avenues have solved my issue until now completely, so I thought I'd come here to see what you guys think. Here's what's happening: My computer is off, and I go to power it on. I press the power switch on the case (Antec Nine Hundred), and nothing seems to happen. Upon further inspection, I see that what this actually does is simply turn on the EPU LED on my motherboard, but doesn't actually boot anything up. I then have to go and flip the main power switch on the power supply off and back on. What this does is turn off all lights on the Motherboard after a few seconds, and turn them all back on (including the EPU LED that was off before I hit the power switch the first time). Now, hitting the power switch works. The machine boots up fine, and starts going through the boot up process. As a side note: My Motherboard is set to "Force BIOS", and every single time I change this to do the opposite, the next time my computer boots up that change reverts itself. I think this may be due to the fact that I am doing the hard reset on the power supply each time, but I'm not sure. I had thought that the Motherboard would keep its BIOS settings unless you did something to the Mobo itself - so this may be a related issue, or something else completely. That's basically it. Once it's on, it's on. It works fine, recognizes all of my hardware, and runs great. All fans/lights in the case work great, and I'm getting standard readings. The next time I go to shut the computer down however, I can expect the same exact process getting it up and running, including being forced to go into BIOS and exit again before I can load Windows. Another side note: If I power on my computer using the power switch DIRECTLY after shutting it down, it powers right back on (I think this is because the EPU LED light doesn't have time to turn off). It looks as if as long as the EPU LED is lit up on the motherboard before I hit the power switch on the case, the thing will boot up fine (although this doesn't explain the "Force BIOS" issue, at least it's something). Any ideas? Thanks guys. P.S. - System Specs Asus P8P67 Rev. 3.1 Motherboard Intel Core i7 2600K Processor 16GB (4x4GB) G-Skill 1600 RAM NVIDIA EVGA GTX 570 Video Card Crucial 128GB SSD HD Corsair 850W Power Supply Seagate 2TB HDD

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  • Amazon EC2 Instance - m1.medium Ubuntu 12.04 - Started to crash three days ago

    - by Joy
    The environment: Amazon EC2 Instance - m1.medium Ubuntu 12.04 Apache 2.2.22 - Running a Drupal Site Using MySQL DB Server RAM info: ~$ free -gt total used free shared buffers cached Mem: 3 1 2 0 0 0 -/+ buffers/cache: 0 2 Swap: 0 0 0 Total: 3 1 2 Hard drive info: Filesystem Size Used Avail Use% Mounted on /dev/xvda1 7.9G 4.7G 2.9G 62% / udev 1.9G 8.0K 1.9G 1% /dev tmpfs 751M 180K 750M 1% /run none 5.0M 0 5.0M 0% /run/lock none 1.9G 0 1.9G 0% /run/shm /dev/xvdb 394G 199M 374G 1% /mnt The problem About two days ago the site started failing becaue the MySQL server was shut down by Apache with the following message: kernel: [2963685.664359] [31716] 106 31716 226946 22748 0 0 0 mysqld kernel: [2963685.664730] Out of memory: Kill process 31716 (mysqld) score 23 or sacrifice child kernel: [2963685.664764] Killed process 31716 (mysqld) total-vm:907784kB, anon-rss:90992kB, file-rss:0kB kernel: [2963686.153608] init: mysql main process (31716) killed by KILL signal kernel: [2963686.169294] init: mysql main process ended, respawning That states that the VM was occupying 0.9GB, but my Ram has 2GB free, so 1GB was still left free. I understand that in Linux applications can allocate more memory than physically available. I don't know if this is the problme, it's the first time that it has started to happen. Obviously, the MySQL server tries to restart, but there's no memory for it apparently and it won't restart. Here is its error log: Plugin 'FEDERATED' is disabled. The InnoDB memory heap is disabled Mutexes and rw_locks use GCC atomic builtins Compressed tables use zlib 1.2.3.4 Initializing buffer pool, size = 128.0M InnoDB: mmap(137363456 bytes) failed; errno 12 Completed initialization of buffer pool Fatal error: cannot allocate memory for the buffer pool Plugin 'InnoDB' init function returned error. Plugin 'InnoDB' registration as a STORAGE ENGINE failed. Unknown/unsupported storage engine: InnoDB [ERROR] Aborting [Note] /usr/sbin/mysqld: Shutdown complete I simply restarted the Mysql service. About two hours later it happened again. I restarted it. Then it happened again 9 hours later. So then I thought of the MaxClients parameter of apache.conf, so I went to check it out. It was set at 150. I decided to drop it down to 60. As so: <IfModule mpm_prefork_module> ... MaxClients 60 </IfModule> <IfModule mpm_worker_module> ... MaxClients 60 </IfModule> <IfModule mpm_event_module> ... MaxClients 60 </IfModule> Once I did that, I had the apache2 service restart and it all went smoothly for 3/4 of a day. Since at night the MySQL service shut down once again, but this time it wasn't killed by the Apache2 service. Instead it called the OOM-Killer with the following message: kernel: [3104680.005312] mysqld invoked oom-killer: gfp_mask=0x201da, order=0, oom_adj=0, oom_score_adj=0 kernel: [3104680.005351] [<ffffffff81119795>] oom_kill_process+0x85/0xb0 kernel: [3104680.548860] init: mysql main process (30821) killed by KILL signal Now I'm out of ideas. Some articles state that the ideal thing to do is change the kernel behaviour with the following (include it to the file /etc/sysctl.conf ) vm.overcommit_memory = 2 vm.overcommit_ratio = 80 So no overcommits will take place. I'm wondering if this is the way to go? Keep in mind I'm no server administrator, I have basic knowldege. Thanks a bunch in advance.

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  • Problems with XP, Office, and PC in general - any ideas?

    - by molecule
    Hi all This may not make a whole lot of sense so pls bear with me... I am about to perform a routine check on one of my user's PC. Some background - the PC has a Xeon processor and 4Gb of RAM and running XP SP3 He has 2xHDD and pagefile is hosted on the secondary HDD (D:) and min/max values are set to 4096. NO pagefile on C: This user has 6 monitors so he has an NVIDIA Quadro NVS440 hosting 4xmonitors and an NVIDIA Quadro NVS290 hosting 2xmonitors. There is a video card driver from NVIDIA which is compatible with both NVS440 and NVS290 and he is on the latest version of that driver. (Note: Make of video cards are different - one is from leadtek and the other from Nvidia) He is a heavy Bloomberg, Outlook, Word, and Excel user and runs two Citrix applications. Other apps are FoxIt PDF and IE. Problems - Outlook and Excel frequently crashes - I am going to perform an Outlook and Excel repair and also check/remove unnecessary addins - will he lose any customizations if I repaired and chose "Restore my shortcuts while repairing" and do not select "Discard my customized settings and restore default settings". Does repair really repair anything? FYI - It stopped crashing ever since i moved a large spreadsheet he has open to his local HDD instead of over the network. This spreadsheet "refreshes" constantly as it is pulling live data to update cells and I suspect it was auto-saving so frequently that it caused crashes if saving over the network. At times, his right click completely fails to respond. His left click works fine but he can't right click on anything in any Window and even on the desktop. Sometimes, he needs to start to close certain applications such as Adobe and the right click will start functioning again. I removed Adobe and installed FoxIt as I figured it was a resource issue but I do not think so as he does have sufficient resources when the problem is happening. Sometimes he can't bring task manager up until he kills certain apps. Definitely sounds like a resource issue but I am not confident that is the root cause. Also not sure if this is related to one of the apps installed but his Start bar flickers (does not completely disappear) intermittently from time to time. The taskbar icons which are hidden appear and then get hidden again as if it was having "fits". I have performed reg scans, malware scans etc but problems do not go away. I am planning to perform sfc /scannow and office repair but would like to know if anyone has any other suggestions. What about setting a "small" pagefile on C:. I have heard that this is recommended and may be the reason why a minidmp file was not generated when he encountered a blue screen. Also, any feedback on his video cards? Do you think different models would cause problems? The drivers seem to work but he only has 2.5Gb out of 4Gb available RAM as I believe the video card chomped up a portion of this. I have recommended creating a new profile for him but due to the amount of customisations he has and the amount of time and effort it will take to get him up and running again, he prefers to bear with the problem than to go down that path. However, at least once a week, his PC acts up and I can't think of any other tools or techniques to rectify his problems. I guess we are at a stage where we just want to "stabilize" things so he won't encounter issues that frequently. Any feedback is very much appreciated.

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  • Parallel processing slower than sequential?

    - by zebediah49
    EDIT: For anyone who stumbles upon this in the future: Imagemagick uses a MP library. It's faster to use available cores if they're around, but if you have parallel jobs, it's unhelpful. Do one of the following: do your jobs serially (with Imagemagick in parallel mode) set MAGICK_THREAD_LIMIT=1 for your invocation of the imagemagick binary in question. By making Imagemagick use only one thread, it slows down by 20-30% in my test cases, but meant I could run one job per core without issues, for a significant net increase in performance. Original question: While converting some images using ImageMagick, I noticed a somewhat strange effect. Using xargs was significantly slower than a standard for loop. Since xargs limited to a single process should act like a for loop, I tested that, and found it to be about the same. Thus, we have this demonstration. Quad core (AMD Athalon X4, 2.6GHz) Working entirely on a tempfs (16g ram total; no swap) No other major loads Results: /media/ramdisk/img$ time for f in *.bmp; do echo $f ${f%bmp}png; done | xargs -n 2 -P 1 convert -auto-level real 0m3.784s user 0m2.240s sys 0m0.230s /media/ramdisk/img$ time for f in *.bmp; do echo $f ${f%bmp}png; done | xargs -n 2 -P 2 convert -auto-level real 0m9.097s user 0m28.020s sys 0m0.910s /media/ramdisk/img$ time for f in *.bmp; do echo $f ${f%bmp}png; done | xargs -n 2 -P 10 convert -auto-level real 0m9.844s user 0m33.200s sys 0m1.270s Can anyone think of a reason why running two instances of this program takes more than twice as long in real time, and more than ten times as long in processor time to complete the same task? After that initial hit, more processes do not seem to have as significant of an effect. I thought it might have to do with disk seeking, so I did that test entirely in ram. Could it have something to do with how Convert works, and having more than one copy at once means it cannot use processor cache as efficiently or something? EDIT: When done with 1000x 769KB files, performance is as expected. Interesting. /media/ramdisk/img$ time for f in *.bmp; do echo $f ${f%bmp}png; done | xargs -n 2 -P 1 convert -auto-level real 3m37.679s user 5m6.980s sys 0m6.340s /media/ramdisk/img$ time for f in *.bmp; do echo $f ${f%bmp}png; done | xargs -n 2 -P 1 convert -auto-level real 3m37.152s user 5m6.140s sys 0m6.530s /media/ramdisk/img$ time for f in *.bmp; do echo $f ${f%bmp}png; done | xargs -n 2 -P 2 convert -auto-level real 2m7.578s user 5m35.410s sys 0m6.050s /media/ramdisk/img$ time for f in *.bmp; do echo $f ${f%bmp}png; done | xargs -n 2 -P 4 convert -auto-level real 1m36.959s user 5m48.900s sys 0m6.350s /media/ramdisk/img$ time for f in *.bmp; do echo $f ${f%bmp}png; done | xargs -n 2 -P 10 convert -auto-level real 1m36.392s user 5m54.840s sys 0m5.650s

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  • Where is my VMware-ws FreeNAS CIFS(ZFS) bottle-neck?

    - by maka
    Background: I'm building a quiet HTPC + NAS that is also supposed to be used for general computer usage. I'm so far generally happy with things, it was just that I was expecting a little better IO performance. I have no clue if my expectations are unreal. The NAS is there as a general purpose file storage and as a media server for XBMC and other devices. ZFS is a requirement. Question: Where is my bottle-neck, and is there anything I can do config wise, to improve my performance? I'm thinking VM-disk settings could be something but I really have no idea where to go since I'm neither experienced with FreeNAS nor VMware-WS. Tests: When I'm on the host OS and copy files (from the SSD) to the CIFS share, I get around 30 Mbytes/sec read and write. When I'm on my laptop laptop, wired to the network, I get about the same specs. The test I've done are with a 16 GB ISO, and with about 200 MB of RARs and I've tried avoiding the RAM-cache by reading different files than the ones I'm writing ( 10 GB). It feels like having less CPU cores is a lot more efficient, since the resource manager in Windows reports less CPU-usage. With 4 cores in VMware, CPU usage was 50-80%, with 1 core it was 25-60%. EDIT: HD ActiveTime was quite high on SSD so I moved the page file, disabled hibernate and enabled Win DiskCache both on SSD and RAID. This resulted in no real performance difference for one file, but if i transferred 2 files the total speed went up to 50 Mbytes/s vs ~40. The ActiveTime avg also went down a lot (to ~20%) but has now higher bursts. DiskIO is on ~ 30-35 Mbytes/s avgs, with ~100Mb bursts. Network is on 200-250Mbits/s with ~45 active TCP connections. Hardware Asus F2A85-M Pro A10-5700 16GB DDR3 1600 OCZ Vertex 2 128GB SSD 2x Generic 1tb 7200 RPM drives as RAID0 (in win7) Intel Gigabit Desktop CT Software Host OS: Win7 (SSD) VMware Worksation 9 (SSD) FreeNAS 8.3 VM (20GB VDisk on SSD) CPU: I've tried 1, 2 and 4 cores. Virtualisation engine, Preferred mode: Automatic 10,24Gb ram 50Gb SCSI VDisk on the RAID0, VDisk is formatted as ZFS and exposed through CIFS through FreeNAS. NIC Bridge, Replicate physical network state Below are two typical process print-outs while I'm transfering one file to the CIFS share. last pid: 2707; load averages: 0.60, 0.43, 0.24 up 0+00:07:05 00:34:26 32 processes: 2 running, 30 sleeping Mem: 101M Active, 53M Inact, 1620M Wired, 2188K Cache, 149M Buf, 8117M Free Swap: 4096M Total, 4096M Free PID USERNAME THR PRI NICE SIZE RES STATE TIME WCPU COMMAND 2640 root 1 102 0 50164K 10364K RUN 0:25 25.98% smbd 1897 root 6 44 0 168M 74808K uwait 0:02 0.00% python last pid: 2746; load averages: 0.93, 0.60, 0.33 up 0+00:08:53 00:36:14 33 processes: 2 running, 31 sleeping Mem: 101M Active, 53M Inact, 4722M Wired, 2188K Cache, 152M Buf, 5015M Free Swap: 4096M Total, 4096M Free PID USERNAME THR PRI NICE SIZE RES STATE TIME WCPU COMMAND 2640 root 1 76 0 50164K 10364K RUN 0:52 16.99% smbd 1897 root 6 44 0 168M 74816K uwait 0:02 0.00% python I'm sorry if my question isn't phrased right, I'm really bad at these kind of things, and it is the first time I post here at SU. I also appreciate any other suggestions to something, I could have missed.

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