Ubuntu
linux package

Consider disabling NEW_FAIR_SLEEPERS

Bug #436342 reported by Johan Kiviniemi on 2009年09月25日

This bug affects 4 people

Affects		Status	Importance	Assigned to	Milestone
linux (Ubuntu)	Fix Released	Medium	Tim Gardner
Karmic	Fix Released	Medium	Tim Gardner

Bug Description

Due to latency problems with desktop interactivity when the NEW_FAIR_SLEEPERS scheduler feature is active, it was disabled by default for Linux 2.6.32, pending the bug being found and fixed.

http://git.kernel.org/?p=linux/kernel/git/x86/linux-2.6-tip.git;a=commitdiff;h=3f2aa307c4d26b4ed6509d0a79e8254c9e07e921

Please consider disabling it in Ubuntu kernels as well.

ProblemType: Bug
Architecture: i386
AudioDevicesInUse:
USER PID ACCESS COMMAND
/dev/snd/controlC0: ion 16762 F.... pulseaudio
CRDA: Error: command ['iw', 'reg', 'get'] failed with exit code 1: nl80211 not found.
Card0.Amixer.info:
Card hw:0 'SB'/'HDA ATI SB at 0xd2400000 irq 16'
Mixer name : 'Realtek ALC268'
Components : 'HDA:10ec0268,103c30f1,00100003 HDA:10573055,103c30f1,00100700'
Controls : 15
Simple ctrls : 12
Date: Fri Sep 25 05:39:59 2009
DistroRelease: Ubuntu 9.10
MachineType: Hewlett-Packard HP Pavilion tx2500 Notebook PC
NonfreeKernelModules: fglrx
Package: linux-image-2.6.31-10-generic-pae 2.6.31-10.35
ProcCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.31-10-generic-pae root=UUID=cb73d396-bca3-4c05-95a2-212a4cecc0b2 ro quiet splash
ProcVersionSignature: Ubuntu 2.6.31-10.35-generic-pae
RelatedPackageVersions:
linux-backports-modules-2.6.31-10-generic-pae 2.6.31-10.12
linux-firmware 1.19
RfKill:

SourcePackage: linux
Uname: Linux 2.6.31-10-generic-pae i686
WpaSupplicantLog:

dmi.bios.date: 02/17/2009
dmi.bios.vendor: Hewlett-Packard
dmi.bios.version: F.0B
dmi.board.asset.tag: Base Board Asset Tag
dmi.board.name: 30F1
dmi.board.vendor: Quanta
dmi.board.version: 97.20
dmi.chassis.type: 10
dmi.chassis.vendor: Quanta
dmi.chassis.version: N/A
dmi.modalias: dmi:bvnHewlett-Packard:bvrF.0B:bd02/17/2009:svnHewlett-Packard:pnHPPaviliontx2500NotebookPC:pvrRev1:rvnQuanta:rn30F1:rvr97.20:cvnQuanta:ct10:cvrN/A:
dmi.product.name: HP Pavilion tx2500 Notebook PC
dmi.product.version: Rev 1
dmi.sys.vendor: Hewlett-Packard

Related branches

lp:ubuntu/karmic/linux-mvl-dove

lp:ubuntu/karmic/linux-fsl-imx51

lp:ubuntu/karmic/linux-ec2

Revision history for this message

Johan Kiviniemi (ion) wrote on 2009年09月25日: #1

AlsaDevices.txt Edit (463 bytes, text/plain; charset="utf-8")
AplayDevices.txt Edit (265 bytes, text/plain; charset="utf-8")
ArecordDevices.txt Edit (264 bytes, text/plain; charset="utf-8")
BootDmesg.gz Edit (13.1 KiB, application/x-gzip)
Card0.Amixer.values.txt Edit (2.3 KiB, text/plain; charset="utf-8")
Card0.Codecs.codec.0.txt Edit (7.4 KiB, text/plain; charset="utf-8")
Card0.Codecs.codec.1.txt Edit (145 bytes, text/plain; charset="utf-8")
CurrentDmesg.txt Edit (16.4 KiB, text/plain; charset="utf-8")
Dependencies.txt Edit (1.4 KiB, text/plain; charset="utf-8")
IwConfig.txt Edit (173 bytes, text/plain; charset="utf-8")
Lspci.txt Edit (14.3 KiB, text/plain; charset="utf-8")
Lsusb.txt Edit (795 bytes, text/plain; charset="utf-8")
PciMultimedia.txt Edit (557 bytes, text/plain; charset="utf-8")
ProcCpuinfo.txt Edit (1.5 KiB, text/plain; charset="utf-8")
ProcEnviron.txt Edit (116 bytes, text/plain; charset="utf-8")
ProcInterrupts.txt Edit (1.3 KiB, text/plain; charset="utf-8")
ProcModules.txt Edit (3.2 KiB, text/plain; charset="utf-8")
UdevDb.txt Edit (104.0 KiB, text/plain; charset="utf-8")
UdevLog.txt Edit (134.0 KiB, text/plain; charset="utf-8")
WifiSyslog.gz Edit (34.8 KiB, application/x-gzip)

Leann Ogasawara (leannogasawara) on 2009年09月25日

Changed in linux (Ubuntu):

importance: Undecided → Medium

status: New → Triaged

Revision history for this message

Tim Gardner (timg-tpi) wrote on 2009年09月29日: #2

http://kernel.ubuntu.com/git?p=ubuntu/ubuntu-karmic.git;a=commit;h=98399d89992af489d26f9b7191dc5502b7c63775

Changed in linux (Ubuntu):

assignee: nobody → Tim Gardner (timg-tpi)

status: Triaged → Fix Committed

Revision history for this message

Launchpad Janitor (janitor) wrote on 2009年10月02日: #3

This bug was fixed in the package linux - 2.6.31-11.38

---------------
linux (2.6.31-11.38) karmic; urgency=low

[ Stefan Bader ]

* [Upstream] acerhdf: Limit modalias matching to supported boards
- LP: #435958

[ Tim Gardner ]

* [Config] Added sata_via to d-i/modules/sata-modules
- LP: #434827
* SAUCE: (drop after 2.6.31) Disable iwl-1000 series wireless adapters
- LP: #439285
* [Upstream] i915: Fix i2c init message
- LP: #409361
* [Config] Add sym53c8xx.ko to virtual sub-flavour
- LP: #439415

[ Upstream Kernel Changes ]

* sched: Disable NEW_FAIR_SLEEPERS for now
- LP: #436342

* ACPI video: ignore buggy _BQC
* ACPI video: work-around BIOS AML bug in _BQC
- LP: #428910
* ALSA: hda - Added quirk to enable sound on Toshiba NB200
- LP: #438318

-- Tim Gardner <email address hidden> 2009年10月01日 13:52:09 -0600

Changed in linux (Ubuntu Karmic):

status: Fix Committed → Fix Released

Revision history for this message

Markus Thielmann (thielmann) wrote on 2009年10月03日: #4

Please notice that disabling NEW_FAIR_SLEEPERS made my system much slower. In fact, Karmic was the first release which allowed me to play tremulous in fullscreen with a nice speed. With NO_NEW_FAIR_SLEEPERS, the system is much slower.

Revision history for this message

Peter Cordes (peter-cordes) wrote on 2009年11月29日: #5

Markus, and anyone else wondering about interactive performance regressions, NEW_FAIR_SLEEPERS is modifiable at run time; just run

echo NEW_FAIR_SLEEPERS | sudo tee /sys/kernel/debug/sched_features

grep --color=tty NEW_FAIR_SLEEPERS /sys/kernel/debug/sched_features

(Ubuntu mounts linux's debugfs at /sys/kernel/debug, not at /debug like you see referenced on the lkml threads talking about this.)

To enable for every reboot, put
echo NEW_FAIR_SLEEPERS > /sys/kernel/debug/sched_features
in /etc/rc.local, or whatever.

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