It might be a cludge, but a workaround might be to disable the
tickless kernel option,  multiple core systems and hyperthreading
would still work with a slight increase in overhead- at least until
this has an accepted patch from the kernel folks.



On 5/12/11, nanog <email address hidden> wrote:
> Looks like the discussion at lkml has been going on for a long time.
>
> http://lkml.org/lkml/2010/4/26/249
>
> This history of this set of patches correlates well with the timeline of
> increased power consumption from phoronix testing. IMO, the loss of
> power consumption does not equal the benefit of increased kernel
> responsiveness especially for laptops.
>
>>I haven't tested this, but single CPU/single core machines might not be
>> affected by this,
> As one would expect this bug is present on hyperthreaded single core atom
> chips.
> For those who want increased battery life on their atom chips...2.6.34 is
> running terrifically in natty.
>
> --
> You received this bug notification because you are a direct subscriber
> of the bug.
> https://bugs.launchpad.net/bugs/760131
>
> Title:
>   Power consumption raised significantly in natty
>
> Status in Release Notes for Ubuntu:
>   Fix Released
> Status in “linux” package in Ubuntu:
>   Confirmed
> Status in “linux” source package in Natty:
>   Confirmed
> Status in “linux” source package in Oneiric:
>   Confirmed
>
> Bug description:
>   This is a regression moving from maverick->natty.  With the same sort
>   of light interactive usage, Battery life has gone from ~4 hours to
>   2:45 or so.
>
>   Running powertop shows the system in P-state "Turbo mode" 10-15% of
>   the time.  Typically this was almost zero in maverick, 98+% of the
>   time maverick was in the lowest state.
>
>   wakeups reported in the 5-600/s range where previously (from memory)
>   it was 200 ish.  i915 driver is high on the list.  This is
>   irrespective of whether running unity or classic desktop.
>
>   ProblemType: Bug
>   DistroRelease: Ubuntu 11.04
>   Package: linux-image-2.6.38-8-generic 2.6.38-8.42
>   Regression: Yes
>   Reproducible: Yes
>   ProcVersionSignature: Ubuntu 2.6.38-8.42-generic 2.6.38.2
>   Uname: Linux 2.6.38-8-generic x86_64
>   AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.23.
>   Architecture: amd64
>   ArecordDevices:
>    **** List of CAPTURE Hardware Devices ****
>    card 0: Intel [HDA Intel], device 0: CONEXANT Analog [CONEXANT Analog]
>      Subdevices: 1/1
>      Subdevice #0: subdevice #0
>   AudioDevicesInUse:
>    USER        PID ACCESS COMMAND
>    /dev/snd/controlC0:  james      2068 F.... pulseaudio
>   CRDA: Error: [Errno 2] No such file or directory
>   Card0.Amixer.info:
>    Card hw:0 'Intel'/'HDA Intel at 0xf2620000 irq 47'
>      Mixer name	: 'Conexant CX20561 (Hermosa)'
>      Components	: 'HDA:14f15051,17aa20ff,00100000'
>      Controls      : 16
>      Simple ctrls  : 8
>   Card29.Amixer.info:
>    Card hw:29 'ThinkPadEC'/'ThinkPad Console Audio Control at EC reg 0x30,
> fw 7XHT24WW-1.06'
>      Mixer name	: 'ThinkPad EC 7XHT24WW-1.06'
>      Components	: ''
>      Controls      : 1
>      Simple ctrls  : 1
>   Card29.Amixer.values:
>    Simple mixer control 'Console',0
>      Capabilities: pswitch pswitch-joined penum
>      Playback channels: Mono
>      Mono: Playback [on]
>   Date: Wed Apr 13 15:03:35 2011
>   EcryptfsInUse: Yes
>   HibernationDevice: RESUME=UUID=bb479652-f524-4abe-b1b0-27646d6deebc
>   InstallationMedia: Ubuntu 10.10 "Maverick Meerkat" - Release Candidate
> amd64 (20100928)
>   MachineType: LENOVO 7465CTO
>   ProcEnviron:
>    LANGUAGE=en_US:en_GB:en
>    PATH=(custom, user)
>    LANG=en_US.UTF-8
>    SHELL=/bin/bash
>   ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.38-8-generic
> root=UUID=266abe9a-19c2-4cc3-9ef7-238b729b6044 ro quiet splash
> libata.force=noncq vt.handoff=7
>   RelatedPackageVersions:
>    linux-restricted-modules-2.6.38-8-generic N/A
>    linux-backports-modules-2.6.38-8-generic  N/A
>    linux-firmware                            1.50
>   RfKill:
>    0: phy0: Wireless LAN
>     Soft blocked: no
>     Hard blocked: no
>   SourcePackage: linux
>   UpgradeStatus: Upgraded to natty on 2011-04-06 (7 days ago)
>   dmi.bios.date: 11/10/2009
>   dmi.bios.vendor: LENOVO
>   dmi.bios.version: 6DET61WW (3.11 )
>   dmi.board.name: 7465CTO
>   dmi.board.vendor: LENOVO
>   dmi.board.version: Not Available
>   dmi.chassis.asset.tag: No Asset Information
>   dmi.chassis.type: 10
>   dmi.chassis.vendor: LENOVO
>   dmi.chassis.version: Not Available
>   dmi.modalias:
> dmi:bvnLENOVO:bvr6DET61WW(3.11):bd11/10/2009:svnLENOVO:pn7465CTO:pvrThinkPadX200s:rvnLENOVO:rn7465CTO:rvrNotAvailable:cvnLENOVO:ct10:cvrNotAvailable:
>   dmi.product.name: 7465CTO
>   dmi.product.version: ThinkPad X200s
>   dmi.sys.vendor: LENOVO
>
>   === Release Notes ===
>
>   Due to a regression inherited from the upstream linux kernel, Natty 11.04
> can exhibit a 10-30% increase in power consumption.  This is a known issue
> which is actively being investigated.  A SRU will be released onced a viable
> solution is found. For more information, please see
>
> http://www.phoronix.com/scan.php?page=article&item=linux_mobile_uffda&num=1
>
> To unsubscribe from this bug, go to:
> https://bugs.launchpad.net/ubuntu-release-notes/+bug/760131/+subscribe
>

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