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Linux Kernel Power Bug Now High Importance In Ubuntu

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  • fewt
    replied
    Originally posted by Michael View Post
    Nope, it doesn't need any update. And users have reported the issue independent of PTS - hence the original Canonical bug report completely independent of that, etc. Most users don't even know how to use the power monitoring features in PTS.
    Are you sure the users reporting the issue have correctly identified the problem? How are you confirming verification of the bug, what does the dataset look like? The Launchpad bug report I saw is questionable at best.

    Leave a comment:


  • Michael
    replied
    Originally posted by fewt View Post
    It is most likely that this is just a misconfiguration blown grossly out of proportion.
    So the mainline kernel PPA, Ubuntu kernel config, Arch Linux config, openSUSE config, Fedora config, and other peoples configurations, etc all went out of whack? There's been independent tests in all of those cases.

    Leave a comment:


  • Michael
    replied
    Originally posted by fewt View Post
    C) The Phoronix test suite itself
    (2.6.37 pretty much required a new version of Powertop, Phoronix test suite probably also needs an update)
    Nope, it doesn't need any update. And users have reported the issue independent of PTS - hence the original Canonical bug report completely independent of that, etc. Most users don't even know how to use the power monitoring features in PTS.

    Leave a comment:


  • fewt
    replied
    Originally posted by yotambien View Post
    It was rhetorical. I assume you read the article and saw the plots. How do you explain them?
    I can't explain them (there isn't enough data), however I believe that the problem could be:

    A) The build options between kernel versions may be different
    B) Something in userspace
    C) The Phoronix test suite itself
    (2.6.37 pretty much required a new version of Powertop, Phoronix test suite probably also needs an update)
    D) The kernel doesn't tune itself for power / battery (requiring a userspace tool like Jupiter)

    It is most likely that this is just a misconfiguration blown grossly out of proportion.

    Leave a comment:


  • yotambien
    replied
    Originally posted by fewt View Post
    Yes. It doesn't change my opinion (or my evidence) that this is not a kernel problem.
    It was rhetorical. I assume you read the article and saw the plots. How do you explain them?

    Leave a comment:


  • fewt
    replied
    Originally posted by yotambien View Post
    Did you see the plots?
    Yes. It doesn't change my opinion (or my evidence) that this is not a kernel problem.

    Leave a comment:


  • yotambien
    replied
    Originally posted by fewt View Post
    Ugh .. Still no evidence but the sky is certainly falling.
    Did you see the plots?

    Leave a comment:


  • Adarion
    replied
    So is this a bug that affects all kernels or just Ubuntu patched ones? I don't understand this fixation on Ubuntu here (and generally). If this happens in vanilla kernels it should not just be reported to Ubuntu but to upstream Kernel development and maybe other distributors. Or did I miss something?

    Leave a comment:


  • fewt
    replied
    Oh, and .. PowerTOP version 1.13

    PowerTOP 1.97 is required to take report on and take advantage of the new powersaving features of kernel 2.6.37 and newer.

    http://lists.lesswatts.org/pipermail...ry/000509.html

    The most common of these have been built into Jupiter.

    Has the Phoronix test suite been updated to use the kernel "perf" infrastructure?

    Leave a comment:


  • fewt
    replied
    Ugh .. Still no evidence but the sky is certainly falling.

    Lenovo T400
    Fuduntu 14.9 (64bit)
    Kernel 2.6.38.4
    Completely idle on battery for ~15 minutes.
    6.36 Watts, 108 wakeups per second.



    Asus Eee PC 1015PEM
    Fuduntu 14.9 (32bit)
    Kernel 2.6.38.4
    Completely idle on battery (as before)
    7.31 Watts, 135.8 wakeups per second.



    As you can see from the images, even my Thinkpad is using only 6ish watts, and well under 200 wakeups per second (closer to 100 really!)..

    The only reason there are 33 reports is because you asked people in your forum to report it!

    http://phoronix.com/forums/showthrea...105#post201105

    Lets take a look at the data supplied in that bug report

    Code:
    Wakeups-from-idle per second : 542.9    interval: 10.0s
    Power usage (ACPI estimate): 14.1W (2.4 hours) (long term: 14.7W,/2.3h)
    
    Top causes for wakeups:
      25.7% (155.8)   [i915] <interrupt>
      13.3% ( 80.3)D  chromium-browse
      17.9% (108.5)   [extra timer interrupt]
       5.7% ( 34.7)   [iwlagn] <interrupt>
       5.1% ( 31.2)   PS/2 keyboard/mouse/touchpad interrupt
       5.0% ( 30.2)   [kernel scheduler] Load balancing tick
       4.9% ( 29.9)   kworker/0:0
       4.4% ( 26.5)   [Rescheduling interrupts] <kernel IPI>
       3.3% ( 20.1)   compiz
       0.0% (  0.0)D  flush-8:0
       3.2% ( 19.6)   desktopcouch-se
       0.1% (  0.7)D  ntop
       1.2% (  7.3)D  thunderbird-bin
       1.7% ( 10.0)   gwibber-service
       1.6% (  9.9)   ubuntuone-syncd
       1.4% (  8.6)   [TLB shootdowns] <kernel IPI>
       1.4% (  8.3)   [acpi] <interrupt>
       0.6% (  3.9)   [ahci] <interrupt>
    The program 'flush-8:0' is writing to file 'ECRYPTFS_FNEK_ENCRYPTED.FWY-tcU' on /dev/sda1.
    This prevents the disk from going to powersave mode.
    - https://launchpadlibrarian.net/69300044/hardcopy.0

    Code:
      25.7% (155.8)   [i915] <interrupt>
      13.3% ( 80.3)D  chromium-browse
      17.9% (108.5)   [extra timer interrupt]
       5.1% ( 31.2)   PS/2 keyboard/mouse/touchpad interrupt
    These are all related.

    375.8 wakeups per second contribute to applications

    What's not reported in the bug though (and probably the root cause), top output.

    Leave a comment:

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