Messages in this thread | | | Date | Wed, 16 Nov 2022 19:17:18 +0800 | Subject | Re: [PATCH] sched/core: use correct cpu_capacity in wake_affine_weight() | From | Honglei Wang <> |
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On 2022/11/16 19:00, Vincent Guittot wrote: > 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) > >
ha, I misunderstand the strategy, thanks for coaching, Vincent.
>> >> /* >> * If sync, adjust the weight of prev_eff_load such that if >> -- >> 2.14.1 >>
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