On Sat, 2010-02-06 at 09:31 +0000, Tom Parker wrote: > On 2 February 2010 21:16, maximilian attems <m...@stro.at> wrote: > > Squeeze will release with 2.6.32 can anyone of you still > > reproduce this? > > > > also please make sure to use latest powertop, aka > > ii powertop 1.13~pre201001 Linux tool to find out what is using power > > palf...@drone:[~] dpkg -l |grep powertop > ii powertop 1.13~pre20100125-1 > Linux tool to find out what is using power > o > palf...@drone:[~] uname -a > Linux drone 2.6.32-1-686 #1 SMP Mon Feb 1 01:37:26 UTC 2010 i686 GNU/Linux > > Attached is powertop.log ('powertop -d') and top.log('top -b -n 1') > > As you can see, the major wakeup is still "Load balancing tick", which > I'm guessing is a translated name for hrtimer_start_expires? I think > the ACPI estimate of 1.1W is a little off though...
hrtimer_start_expires() is a generic function in the kernel to schedule a wakeup by the high-resolution timer. In 2.6.32 it is an inline function that calls hrtimer_start_range_ns(). Powertop recognises and relabels some specific calling sequences, including this one. If I understand correctly, these are scheduler ticks that periodically interrupt the running task (preemption). However, on a kernel compiled with the NOHZ option (as Debian's kernel images are) this should never wake the system up - scheduler ticks are disabled when there are no tasks ready to run and no other timers due to expire before the next tick. I can only suggest you report this upstream at <http://bugzilla.kernel.org>. Use product 'Process Management', component 'Scheduler'. Let us know the bug number so we can track it. > So, doesn't look fixed. I'm currently at FOSDEM if anyone with more > knowledge wants to borrow my laptop to do more debugging on this. Sorry I didn't have the time to do this. This is not really my area of expertise though. Ben. -- Ben Hutchings Humour is the best antidote to reality.
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