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SubjectRe: [PATCH v3 15/22] sched: log the cpu utilization at rq
On Fri, Jan 11, 2013 at 03:30:30AM +0000, Alex Shi wrote:
> On 01/10/2013 07:40 PM, Morten Rasmussen wrote:
> >> > #undef P64
> >> > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> >> > index ee015b8..7bfbd69 100644
> >> > --- a/kernel/sched/fair.c
> >> > +++ b/kernel/sched/fair.c
> >> > @@ -1495,8 +1495,12 @@ static void update_cfs_rq_blocked_load(struct cfs_rq *cfs_rq, int force_update)
> >> >
> >> > static inline void update_rq_runnable_avg(struct rq *rq, int runnable)
> >> > {
> >> > + u32 period;
> >> > __update_entity_runnable_avg(rq->clock_task, &rq->avg, runnable);
> >> > __update_tg_runnable_avg(&rq->avg, &rq->cfs);
> >> > +
> >> > + period = rq->avg.runnable_avg_period ? rq->avg.runnable_avg_period : 1;
> >> > + rq->util = rq->avg.runnable_avg_sum * 100 / period;
> > The existing tg->runnable_avg and cfs_rq->tg_runnable_contrib variables
> > both holds
> > rq->avg.runnable_avg_sum / rq->avg.runnable_avg_period scaled by
> > NICE_0_LOAD (1024). Why not use one of the existing variables instead of
> > introducing a new one?
>
> we want to a rq variable that reflect the utilization of the cpu, not of
> the tg

It is the same thing for the root tg. You use exactly the same variables
for calculating rq->util as is used to calculate both tg->runnable_avg and
cfs_rq->tg_runnable_contrib in __update_tg_runnable_avg(). The only
difference is that you scale by 100 while __update_tg_runnable_avg()
scale by NICE_0_LOAD.

Morten

> --
> Thanks Alex
> --
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