Messages in this thread | | | From | Vincent Guittot <> | Date | Wed, 16 Nov 2022 12:00:24 +0100 | Subject | Re: [PATCH] sched/core: use correct cpu_capacity in wake_affine_weight() |
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On Wed, 16 Nov 2022 at 10:12, Honglei Wang <wanghonglei@didiglobal.com> wrote: > > It seems make more sense to do the load weight calculation with > respective cpu_capacity. > > Signed-off-by: Honglei Wang <wanghonglei@didiglobal.com> > --- > kernel/sched/fair.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index e4a0b8bd941c..a9f75040969b 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -6262,13 +6262,13 @@ wake_affine_weight(struct sched_domain *sd, struct task_struct *p, > this_eff_load += task_load; > if (sched_feat(WA_BIAS)) > this_eff_load *= 100; > - this_eff_load *= capacity_of(prev_cpu); > + this_eff_load *= capacity_of(this_cpu); > > prev_eff_load = cpu_load(cpu_rq(prev_cpu)); > prev_eff_load -= task_load; > if (sched_feat(WA_BIAS)) > prev_eff_load *= 100 + (sd->imbalance_pct - 100) / 2; > - prev_eff_load *= capacity_of(this_cpu); > + prev_eff_load *= capacity_of(prev_cpu);
we want to test : (cpu_load(this_rq) + task_h_load(p) ) / capacity_of(this_cpu) < cpu_load(prev_rq) / capacity_of(prev_cpu)
but instead of doing expensive division, we do the below which gives the same result (cpu_load(this_rq) + task_h_load(p) ) * capacity_of(prev_cpu) < cpu_load(prev_rq) * capacity_of(this_cpu)
> > /* > * If sync, adjust the weight of prev_eff_load such that if > -- > 2.14.1 >
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