Re: [.32-rc3] scheduler: iwlagn consistently high in "waiting forCPU"

From: Mike Galbraith
Date: Thu Oct 08 2009 - 09:19:33 EST


On Thu, 2009-10-08 at 15:09 +0200, Frans Pop wrote:
> On Thursday 08 October 2009, Mike Galbraith wrote:
> > Care to try a patch?
> >
> > latencytop: only account on-runqueue wait time as being scheduler
> > latency.
> >
> > Latencytop was accounting uninterruptible and interruptible sleep time
> > up to 5ms, which is not the latency the user is looking for. Account
> > time waiting on-runqueue instead. Also add a clock update to
> > update_curr() for the case where there's nobody home. When coming out
> > of idle with NO_HZ, not updating the clock leads to bogus max latency
> > report.
>
> With this patch the high values for iwlagn and phy0 are gone. The values
> now match roughly with the output of your script.
>
> If (un)interruptible sleep is worth displaying in latencytop then maybe it
> should be identified as a separate cause instead of lumped under "waiting
> for CPU"?

That's what I was just thing about trying, add a cause sleep.

> > TODO: Figure out where the heck empty braces come from.
>
> I also see these lines with "[]" sometimes; looks to come from 'sleep'.
>
> And I still see lines with only a "." as the cause; this seems specific to
> targets marked with the penguin (work queues?).
>
> > Signed-off-by: Mike Galbraith <efault@xxxxxx>
> > Arjan van de Ven <arjan@xxxxxxxxxxxxx>
> > Cc: Ingo Molnar <mingo@xxxxxxx>
> > Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
> > LKML-Reference: <new-submission>
>
> If Arjan is happy with the patch, please add my:

Probably just a diagnostic, but...

> Reported-and-tested-by: Frans Pop <elendil@xxxxxxxxx>

Saved.

-Mike

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/