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    SubjectRe: kmemleak, cpu usage jump out of nowhere
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    On Wed, Jul 14, 2010 at 11:54 AM, Zeno Davatz <zdavatz@gmail.com> wrote:
    > On Wed, Jul 14, 2010 at 10:38 AM, Pekka Enberg <penberg@cs.helsinki.fi> wrote:
    >> Zeno Davatz wrote:
    >>>
    >>> On Wed, Jul 14, 2010 at 10:31 AM, Damien Wyart <damien.wyart@free.fr>
    >>> wrote:
    >>>
    >>>>> On Wed, Jul 14, 2010 at 9:12 AM, Zeno Davatz <zdavatz@gmail.com> wrote:
    >>>>>>
    >>>>>> I got a new Intel core-8 i7 processor.
    >>>>>> I am on kernel uname -a
    >>>>>> Linux zenogentoo 2.6.35-rc5 #97 SMP Tue Jul 13 16:13:25 CEST 2010 i686
    >>>>>> Intel(R) Core(TM) i7 CPU 960 @ 3.20GHz GenuineIntel GNU/Linux
    >>>>>> Sometimes in the middle of nowhere all of a sudden all of my 8-cores
    >>>>>> are at 100% CPU usage and my machine really lags and hangs and is not
    >>>>>> useable anymore. Some random process just grabs a bunch CPUs according
    >>>>>> to htop.
    >>>>
    >>>> * Pekka Enberg <penberg@cs.helsinki.fi> [2010-07-14 11:05]:
    >>>>>
    >>>>> Why did you enable CONFIG_DEBUG_KMEMLEAK? Memory leak scanning is
    >>>>> likely the source of these pauses.
    >>>>
    >>>> I am seeing the same problem with a Core i7 920 and 2.6.35-rc5, and I do
    >>>> not have CONFIG_DEBUG_KMEMLEAK enabled, so I think this is not related.
    >>>>
    >>>> I do not see anything special in the logs, just the load becoming mad
    >>>> and almost preventing ssh access. I've been seeing that since the first
    >>>> 2.6.35 rc I tested (-rc2 or -rc3, I don't remember) and I did not have
    >>>> time to report it before but I was surprised nobody else did. No problem
    >>>> with 2.6.34 and 2.6.34.1.
    >>>
    >>> same with me. My last build I tested was 2.6.34-rc7. No problems
    >>> there. No CPU jumps out of nowhere.
    >>>
    >>> It is like any application all of a sudden use 400% CPU i.e. htop.
    >>
    >> Interesting. Lets CC some scheduler folks for help.
    >
    > Once it is gdm, once it is firefox-bin once it is htop. Its really od.
    > Nothing crashes one of those just uses lots of CPU. The machine just
    > gets really slow and then calms down again and everything is back to
    > normal.

    That's the part that makes me think it's scheduler and/or cpufreq related.

    > ;)
    >
    > Maybe a bad temper?

    Yeah, maybe Tux is having a bad day. :-)


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