Messages in this thread | | | Subject | Re: [PATCH v3] sched/cpufreq: optimize cpufreq update kicker to avoid update multiple times | From | "Rafael J. Wysocki" <> | Date | Fri, 22 Apr 2016 14:04:56 +0200 |
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[Added linux-pm to the CC - can you please do so for PM-related patches in the future?]
On 4/22/2016 11:07 AM, Wanpeng Li wrote: > From: Wanpeng Li <wanpeng.li@hotmail.com> > > Sometimes delta_exec is 0 due to update_curr() is called multiple times, > this is captured by: > > u64 delta_exec = rq_clock_task(rq) - curr->se.exec_start; > > This patch optimizes the cpufreq update kicker by bailing out when nothing > changed, it will benefit the upcoming schedutil, since otherwise it will > (over)react to the special util/max combination. > > Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
The changelog looks better now, thanks!
Peter, do I think correctly that you're going to take care of this one? Or do you want me to take it?
> --- > v1 -> v2: > * add From: head > v2 -> v3: > * update changelog > > kernel/sched/deadline.c | 8 ++++---- > kernel/sched/rt.c | 8 ++++---- > 2 files changed, 8 insertions(+), 8 deletions(-) > > diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c > index affd97e..8f9b5af 100644 > --- a/kernel/sched/deadline.c > +++ b/kernel/sched/deadline.c > @@ -717,10 +717,6 @@ static void update_curr_dl(struct rq *rq) > if (!dl_task(curr) || !on_dl_rq(dl_se)) > return; > > - /* Kick cpufreq (see the comment in linux/cpufreq.h). */ > - if (cpu_of(rq) == smp_processor_id()) > - cpufreq_trigger_update(rq_clock(rq)); > - > /* > * Consumed budget is computed considering the time as > * observed by schedulable tasks (excluding time spent > @@ -736,6 +732,10 @@ static void update_curr_dl(struct rq *rq) > return; > } > > + /* kick cpufreq (see the comment in linux/cpufreq.h). */ > + if (cpu_of(rq) == smp_processor_id()) > + cpufreq_trigger_update(rq_clock(rq)); > + > schedstat_set(curr->se.statistics.exec_max, > max(curr->se.statistics.exec_max, delta_exec)); > > diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c > index c41ea7a..19e1306 100644 > --- a/kernel/sched/rt.c > +++ b/kernel/sched/rt.c > @@ -953,14 +953,14 @@ static void update_curr_rt(struct rq *rq) > if (curr->sched_class != &rt_sched_class) > return; > > - /* Kick cpufreq (see the comment in linux/cpufreq.h). */ > - if (cpu_of(rq) == smp_processor_id()) > - cpufreq_trigger_update(rq_clock(rq)); > - > delta_exec = rq_clock_task(rq) - curr->se.exec_start; > if (unlikely((s64)delta_exec <= 0)) > return; > > + /* Kick cpufreq (see the comment in linux/cpufreq.h). */ > + if (cpu_of(rq) == smp_processor_id()) > + cpufreq_trigger_update(rq_clock(rq)); > + > schedstat_set(curr->se.statistics.exec_max, > max(curr->se.statistics.exec_max, delta_exec)); >
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