** Description changed: The standard ubuntu kernel uses 100hz timer resolution (for amd64, 250hz for x86). I don't know why this is, I'm assuming it's just used because it's the kernel default or something? Either way it's not ideal for typical desktop usage, 100hz especially really does introduce noticeable lag, can cause skips in audio and just generally makes the whole desktop tend to microstutter a bit. According to Con Kolivas (the guy who used to maintain the -ck patches and who - wrote the original completely fair scheduler for linux) the kernel devs - ran a lot of tests and for most desktop use cases the performance impact - was negligable, in some corner cases it caused up to a 1% performance - drop, whereas the desktop interactivity gains were very noticeable by - the users. + wrote the original completely fair [staircase] scheduler for linux) the + kernel devs ran some tests and for most desktop use cases, using 1000hz + over 100hz timers caused pretty much no performance impact, whilst in + some corner cases it caused up to a 1% performance drop. On the other + hand, the desktop interactivity gains were very noticeable by the users. DISCLAIMER: Of course it's always hard to justify these sorts of claims because desktop responsiveness is a notoriously woolly and hard to measure thing, but without at least suggesting some solutions I don't see how we can improve it, hence this bug report. Personally I think that a 1% performance drop is totally acceptable on a desktop in order to obtain a much smoother running system. In my opinion (one which I'd sincerely hope most people here share) we should be aiming at making Ubuntu Desktop the best desktop O/S you can have, which means providing the best user experience. With lower resolution timers, you can occasionally have audio skipping, your mouse inputs aren't always responded to quite as fast, your compiz is a bit more jerky, your games can sometimes lag for fractions of a second etc etc etc. Just general responsiveness suffers in the case of low res timers. Now I know these sort of claims are often made and because it's desktop interactivity, it's very hard to prove anything because it's subjective, but I encourage anybody reading this to compile a kernel with both 100hz timers and 1000hz timers and have a play around, just use the desktop like you normally would, typing text, moving windows, playing music etc. - I'm sure you will notice quite a difference. And hey, if I don't report - a bug and encourage some discussion on the topic, nothing gets done at - all, which is much worse ;-). - - ProblemType: Bug - Architecture: amd64 - AudioDevicesInUse: - USER PID ACCESS COMMAND - /dev/snd/controlC1: sam 2051 F.... pulseaudio - /dev/snd/pcmC1D0c: sam 2051 F...m pulseaudio - /dev/snd/controlC0: sam 2051 F.... pulseaudio - /dev/snd/pcmC0D0p: sam 2051 F...m pulseaudio - CRDA: Error: [Errno 2] No such file or directory - Card0.Amixer.info: - Card hw:0 'Revolution71'/'M Audio Revolution-7.1 at 0xec00, irq 17' - Mixer name : 'ICE1724 - multitrack' - Components : '' - Controls : 27 - Simple ctrls : 22 - Card1.Amixer.info: - Card hw:1 'Intel'/'HDA Intel at 0xf9ff8000 irq 22' - Mixer name : 'Realtek ALC1200' - Components : 'HDA:10ec0888,104382fe,00100101' - Controls : 40 - Simple ctrls : 22 - Date: Thu Nov 5 01:20:24 2009 - DistroRelease: Ubuntu 9.10 - MachineType: System manufacturer P5QL PRO - NonfreeKernelModules: nvidia - Package: linux-generic 2.6.31.14.27 - ProcCmdLine: root=UUID=f9c198f6-df39-49bf-9444-a1ad71d16bf6 ro elevator=deadline quiet splash - ProcEnviron: - LANG=en_GB.UTF-8 - SHELL=/bin/bash - RfKill: - - SourcePackage: linux-meta - Uname: Linux 2.6.31.5-bfs304-test-ice1724patch x86_64 - WpaSupplicantLog: - - dmi.bios.date: 11/28/2008 - dmi.bios.vendor: American Megatrends Inc. - dmi.bios.version: 0902 - dmi.board.asset.tag: To Be Filled By O.E.M. - dmi.board.name: P5QL PRO - dmi.board.vendor: ASUSTeK Computer INC. - dmi.board.version: Rev 1.xx - dmi.chassis.asset.tag: Asset-1234567890 - dmi.chassis.type: 3 - dmi.chassis.vendor: Chassis Manufacture - dmi.chassis.version: Chassis Version - dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr0902:bd11/28/2008:svnSystemmanufacturer:pnP5QLPRO:pvrSystemVersion:rvnASUSTeKComputerINC.:rnP5QLPRO:rvrRev1.xx:cvnChassisManufacture:ct3:cvrChassisVersion: - dmi.product.name: P5QL PRO - dmi.product.version: System Version - dmi.sys.vendor: System manufacturer + I'm sure you will notice quite a difference. I would politely request + that those in charge of setting these kernel configuration options try + out the different timer resolutions and have a play around and see if it + actually does make an improvement or not.
-- Stock ubuntu desktop kernel should be using 1000hz timer resolution https://bugs.launchpad.net/bugs/474977 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
