SIS_AVG_CPU was introduced as a means of avoiding a search when the average search cost indicated that the search would likely fail. It was a blunt instrument and disabled by 4c77b18cf8b7 ("sched/fair: Make select_idle_cpu() more aggressive") and later replaced with a proportional search depth by 1ad3aaf3fcd2 ("sched/core: Implement new approach to scale select_idle_cpu()").
While there are corner cases where SIS_AVG_CPU is better, it has now been disabled for almost three years. As the intent of SIS_PROP is to reduce the time complexity of select_idle_cpu(), lets drop SIS_AVG_CPU and focus on SIS_PROP as a throttling mechanism. Signed-off-by: Mel Gorman <mgor...@techsingularity.net> --- kernel/sched/fair.c | 3 --- kernel/sched/features.h | 1 - 2 files changed, 4 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 98075f9ea9a8..23934dbac635 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -6161,9 +6161,6 @@ static int select_idle_cpu(struct task_struct *p, struct sched_domain *sd, int t avg_idle = this_rq()->avg_idle / 512; avg_cost = this_sd->avg_scan_cost + 1; - if (sched_feat(SIS_AVG_CPU) && avg_idle < avg_cost) - return -1; - if (sched_feat(SIS_PROP)) { u64 span_avg = sd->span_weight * avg_idle; if (span_avg > 4*avg_cost) diff --git a/kernel/sched/features.h b/kernel/sched/features.h index 68d369cba9e4..e875eabb6600 100644 --- a/kernel/sched/features.h +++ b/kernel/sched/features.h @@ -54,7 +54,6 @@ SCHED_FEAT(TTWU_QUEUE, true) /* * When doing wakeups, attempt to limit superfluous scans of the LLC domain. */ -SCHED_FEAT(SIS_AVG_CPU, false) SCHED_FEAT(SIS_PROP, true) /* -- 2.26.2