Messages in this thread | | | From | Valentin Schneider <> | Subject | Re: [PATCH 1/3] sched/fair: Make cpu_overutilized() EAS dependent | Date | Mon, 20 Dec 2021 17:17:09 +0000 |
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On 20/12/21 12:43, Vincent Donnefort wrote: > On a system with Energy Aware Scheduling (EAS), tasks are placed according > to their energy consumption estimation and load balancing is disabled to > not break that energy biased placement. If the system becomes > overutilized, i.e. one of the CPU has too much utilization, energy > placement would then be disabled, in favor of Capacity-Aware Scheduling > (CAS), including load balancing. This is the sole usage for > rd->overutilized. Hence, there is no need to raise it for !EAS systems. > > Fixes: 2802bf3cd936 ("sched/fair: Add over-utilization/tipping point indicator")
I'm not sure a Fixes: is warranted, this does not fix any misbehaviour or performance regression (even if this might gain us a few extra IPS by not writing 1's to rd->overutilized on SMP systems, note that this still gives us writes of 0's).
Regardless:
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
> Signed-off-by: Vincent Donnefort <vincent.donnefort@arm.com> > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index 095b0aa378df..e2f6fa14e5e7 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -5511,7 +5511,8 @@ static inline void hrtick_update(struct rq *rq) > #ifdef CONFIG_SMP > static inline bool cpu_overutilized(int cpu) > { > - return !fits_capacity(cpu_util_cfs(cpu), capacity_of(cpu)); > + return sched_energy_enabled() && > + !fits_capacity(cpu_util_cfs(cpu), capacity_of(cpu)); > } > > static inline void update_overutilized_status(struct rq *rq) > -- > 2.25.1
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