Messages in this thread Patch in this message | | | From | Mel Gorman <> | Subject | [PATCH 06/10] sched/fair: Clear the target CPU from the cpumask of CPUs searched | Date | Thu, 3 Dec 2020 14:11:20 +0000 |
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The target CPU is definitely not idle in both select_idle_core and select_idle_cpu. For select_idle_core(), the SMT is potentially checked unnecessarily as the core is definitely not idle if the target is busy. For select_idle_cpu(), the first CPU checked is simply a waste.
Signed-off-by: Mel Gorman <mgorman@techsingularity.net> --- kernel/sched/fair.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 68dd9cd62fbd..1d8f5c4b4936 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -6077,6 +6077,7 @@ static int select_idle_core(struct task_struct *p, struct sched_domain *sd, int return -1; cpumask_and(cpus, sched_domain_span(sd), p->cpus_ptr); + __cpumask_clear_cpu(target, cpus); for_each_cpu_wrap(core, cpus, target) { bool idle = true; @@ -6181,6 +6182,7 @@ static int select_idle_cpu(struct task_struct *p, struct sched_domain *sd, int t time = cpu_clock(this); cpumask_and(cpus, sched_domain_span(sd), p->cpus_ptr); + __cpumask_clear_cpu(target, cpus); for_each_cpu_wrap(cpu, cpus, target) { schedstat_inc(this_rq()->sis_scanned); -- 2.26.2
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