Comment 152 for bug 524281

Xcausing wakeups may coincide with enabled composing. On my Intel
chipset graphics, this
causes approx. an additional 50 wakeups per second. If composing is
disabled, everything is
back to normal. On another notebook with a Radeon 5470 (using fglrx),
there was no such
difference.

In addition, it also seems that X increases the load to rather large
levels, despite being idle.
With Ubuntu 10.10 (and kernel newer than 2.6.31) I have observed loads
around 0.7, without
anything showing up in top.

2010/11/4 Peter Sasi <email address hidden>:
>
> ** Attachment added: "powertop-dump-5min-2.6.36-020636-generic.txt"
>   https://bugs.launchpad.net/ubuntu/+source/linux/+bug/524281/+attachment/1722665/+files/powertop-dump-5min-2.6.36-020636-generic.txt
>
> ** Also affects: xorg (Ubuntu)
>   Importance: Undecided
>       Status: New
>
> --
> Tens of wakes per second in "[kernel scheduler] Load balancing tick" on Core 2 Duo even with only 1 core enabled
> https://bugs.launchpad.net/bugs/524281
> You received this bug notification because you are a direct subscriber
> of the bug.
>
> Status in “linux” package in Ubuntu: Triaged
> Status in “xorg” package in Ubuntu: New
> Status in Arch Linux: New
> Status in “linux-2.6” package in Debian: Incomplete
>
> Bug description:
> powertop reports many wakes per second (quantity depending on system)  in "[kernel scheduler] Load balancing tick" task, rising with little load, on many kinds of multi-core (?) systems (original report was on a Core 2 Duo processor (T6500) with a single core enabled (multicore disabled in BIOS)).
>
> Cause of the problem:
> With kernel 2.6.32, there came a patch to the scheduler that introduced this problem (that was backported to some other versions as well). Even though this problem occurred first in Lucid, it is NOT specific to Lucid or Ubuntu at all (Debian bug report at http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=521944, reproducable in Arch Linux as well). Work is ongoing to get things straight in kernel, but it will take a long time until this reaches Ubuntu (see http://lkml.org/lkml/2010/7/6/172).
>
> Workarounds that DO NOT work (may improve situation but not solve it):
> - maxcpus=1
> - noapic
> - nosmp
> - nolapic
> - use mainline kernel
>
> Workarounds that DO (probably) work:
> - tip version of kernel (git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip.git, from http://lkml.org/lkml/2010/7/8/75)
> - use maverick's kernel with applied patches (https://launchpad.net/~brian-rogers/+archive/power, from comment #80)
>
> ProblemType: Bug
> AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.21.
> Architecture: i386
> ArecordDevices:
>  **** List of CAPTURE Hardware Devices ****
>  card 0: Intel [HDA Intel], device 0: ALC269 Analog [ALC269 Analog]
>    Subdevices: 1/1
>    Subdevice #0: subdevice #0
> AudioDevicesInUse:
>  USER        PID ACCESS COMMAND
>  /dev/snd/controlC0:  etrusco    1606 F.... pulseaudio
>                       etrusco   15151 F.... foobar2000.exe
> CRDA: Error: [Errno 2] No such file or directory
> Card0.Amixer.info:
>  Card hw:0 'Intel'/'HDA Intel at 0xfddf8000 irq 22'
>    Mixer name   : 'Realtek ALC269'
>    Components   : 'HDA:10ec0269,1b0a4009,00100004 HDA:11c11040,1b0a4007,00100200'
>    Controls      : 19
>    Simple ctrls  : 11
> Card1.Amixer.info:
>  Card hw:1 'HDMI'/'HDA ATI HDMI at 0xfebec000 irq 17'
>    Mixer name   : 'ATI R6xx HDMI'
>    Components   : 'HDA:1002aa01,00aa0100,00100100'
>    Controls      : 4
>    Simple ctrls  : 1
> Card1.Amixer.values:
>  Simple mixer control 'IEC958',0
>    Capabilities: pswitch pswitch-joined penum
>    Playback channels: Mono
>    Mono: Playback [on]
> Date: Fri Feb 19 05:25:42 2010
> DistroRelease: Ubuntu 10.04
> EcryptfsInUse: Yes
> MachineType: Philco PHN10XXX.
> Package: linux-image-2.6.32-13-generic 2.6.32-13.18
> ProcCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.32-13-generic root=UUID=d482e94f-9370-4ad2-9536-986541003db5 ro acpi.power_nocheck=1 acpi_osi=linux radeon.blacklist=yes
> ProcEnviron:
>  LANG=en_US.UTF-8
>  SHELL=/bin/bash
> ProcVersionSignature: Ubuntu 2.6.32-13.18-generic
> Regression: No
> RelatedPackageVersions: linux-firmware 1.29
> Reproducible: Yes
> RfKill:
>  0: phy0: Wireless LAN
>   Soft blocked: no
>   Hard blocked: no
> SourcePackage: linux
> TestedUpstream: No
> Uname: Linux 2.6.32-13-generic i686
> dmi.bios.date: 06/01/2009
> dmi.bios.vendor: American Megatrends Inc.
> dmi.bios.version: 1.01
> dmi.board.asset.tag: To Be Filled By O.E.M.
> dmi.board.vendor: PEGATRON CORP.
> dmi.board.version: To be filled by O.E.M.
> dmi.chassis.asset.tag: To Be Filled By O.E.M.
> dmi.chassis.type: 10
> dmi.chassis.vendor: PEGATRON CORP.
> dmi.chassis.version: To Be Filled By O.E.M.
> dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr1.01:bd06/01/2009:svnPhilco:pnPHN10XXX.:pvr1.01:rvnPEGATRONCORP.:rn:rvrTobefilledbyO.E.M.:cvnPEGATRONCORP.:ct10:cvrToBeFilledByO.E.M.:
> dmi.product.name: PHN10XXX.
> dmi.product.version: 1.01
> dmi.sys.vendor: Philco
>
>
>
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