Messages in this thread | | | Subject | Re: [PATCH 1/2] sched/fair: move cpufreq hook to update_cfs_rq_load_avg() | From | Dietmar Eggemann <> | Date | Mon, 28 Mar 2016 14:02:30 +0200 |
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Hi Steve,
these patches fall into the bucket of 'optimization of updating the value only if the root cfs_rq util has changed' as discussed in '[PATCH 5/8] sched/cpufreq: pass sched class into cpufreq_update_util' of Mike T's current series '[PATCH 0/8] schedutil enhancements', right?
I wonder if it makes sense to apply them before a proper 'capacity vote aggregation from CFS/RT/DL' has been agreed upon?
Otherwise I agree with the changes in your 3 patches (inc. "[RFC PATCH] sched/fair: call cpufreq hook in additional paths") to only invoke cpufreq_update_util() if &rq->cfs.avg.util_avg has really changed.
On 03/22/2016 01:21 AM, Steve Muckle wrote: > The cpufreq hook should be called whenever the root cfs_rq > utilization changes so update_cfs_rq_load_avg() is a better > place for it. The current location is not invoked in the > enqueue_entity() or update_blocked_averages() paths. > > Suggested-by: Vincent Guittot <vincent.guittot@linaro.org> > Signed-off-by: Steve Muckle <smuckle@linaro.org> > --- > kernel/sched/fair.c | 50 ++++++++++++++++++++++++++------------------------ > 1 file changed, 26 insertions(+), 24 deletions(-) > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index 46d64e4ccfde..d418deb04049 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -2825,7 +2825,9 @@ static inline u64 cfs_rq_clock_task(struct cfs_rq *cfs_rq); > static inline int update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq) > { > struct sched_avg *sa = &cfs_rq->avg; > + struct rq *rq = rq_of(cfs_rq); > int decayed, removed = 0; > + int cpu = cpu_of(rq); > > if (atomic_long_read(&cfs_rq->removed_load_avg)) { > s64 r = atomic_long_xchg(&cfs_rq->removed_load_avg, 0); > @@ -2840,7 +2842,7 @@ static inline int update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq) > sa->util_sum = max_t(s32, sa->util_sum - r * LOAD_AVG_MAX, 0); > } > > - decayed = __update_load_avg(now, cpu_of(rq_of(cfs_rq)), sa, > + decayed = __update_load_avg(now, cpu, sa, > scale_load_down(cfs_rq->load.weight), cfs_rq->curr != NULL, cfs_rq);
Why did you change these 3 lines above? You reverted this back in "[RFC PATCH] sched/fair: call cpufreq hook in additional paths".
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