Messages in this thread | | | Date | Wed, 4 Jun 2014 14:09:18 +0100 | From | Morten Rasmussen <> | Subject | Re: [PATCH v2 08/11] sched: get CPU's activity statistic |
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On Wed, Jun 04, 2014 at 12:52:46PM +0100, Vincent Guittot wrote: > On 4 June 2014 13:23, Morten Rasmussen <morten.rasmussen@arm.com> wrote: > > I get: > > > > A: 15/40 ms = 37.5% > > B: 20/40 ms = 50% > > > > Schedule: > > > > | 5 ms | 5 ms | 5 ms | 5 ms | 5 ms | 5 ms | 5 ms | 5 ms | 5 ms | > > A: run rq run ----------- sleeping ------------- run > > B: rq run rq run ---- sleeping ------------- rq > > > >> and CPU runnable will be 60% too > > > > rq->avg.runnable_avg_sum should be 50%. You have two tasks running for > > 20 ms every 40 ms. > > > > Right? > > ok, i see the misunderstood. > it's depends of what we mean by runnable. You take the % of time > whereas i take the runnable_avg_sum/period
Right. There is a difference.
> > so A is on_rq 15/40 ms = 37.5% of the time which gives a > runnable_avg_sum/runnable_avg_period of 47% > B is on_rq 20/40 ms = 50% of the time which gives a > runnable_avg_sum/runnable_avg_period of 60% > and CPU has a task on its rq 20/40ms = 50% of the time which gives a > runnable_avg_sum/runnable_avg_period of 60%
Yes, that seems about right.
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