Re: [PATCH 5/5] Account ksoftirqd time as cpustat softirq -v2

From: Peter Zijlstra
Date: Wed Dec 22 2010 - 09:06:33 EST


On Wed, 2010-12-22 at 05:59 -0800, Venkatesh Pallipadi wrote:
> > So you add the ksoftirqd runtime as softirq time in the /proc/stat
> > output?
> >
> > That seems dubious...
> >
>
> Yes. Thats similar to what we do today. As long as we are in softirq,
> whether bottomhalf or ksoftirqd, we account the tick as softirq time
> in /proc/stat.
> I thought it also makes sense from user perspective. They want to know
> how much time are we currently spending serving softirqs and hardirqs.
> It is better to get that information at one place, instead of say look
> at /proc/stat and add percpu ksoftirqd time to it. I mean,
> user/administrator does not have to care whether ksoftirqd is involved
> or not to know how much time was spend serving softirqs.
>
But ksoftirqd time is also counted as sys time, so somewhere this won't
add up to 100%.
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