Messages in this thread Patch in this message | | | From | Yicong Yang <> | Subject | [PATCH] sched/fair: Track target domain's avg_scan_cost in select_idle_cpu | Date | Sat, 11 Dec 2021 18:43:24 +0800 |
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We regulate the LLC domain scan in select_idle_cpu() by comparing the average scan cost of this_sd against the average idle time of this_rq. This is correct when the domain to scan is the LLC domain of this cpu. But when the domain to scan is different from this LLC domain, we'll have an inaccurate estimation of the scan cost on the target domain as this_sd->avg_scan_cost contains contributions of scanning other domains besides the target domain.
Track the avg_scan_cost of the target domain to make the estimation more accurate.
Signed-off-by: Yicong Yang <yangyicong@hisilicon.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 6e476f6d9435..6301740d98cb 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -6267,7 +6267,7 @@ static int select_idle_cpu(struct task_struct *p, struct sched_domain *sd, bool } avg_idle = this_rq->wake_avg_idle; - avg_cost = this_sd->avg_scan_cost + 1; + avg_cost = sd->avg_scan_cost + 1; span_avg = sd->span_weight * avg_idle; if (span_avg > 4*avg_cost) @@ -6305,7 +6305,7 @@ static int select_idle_cpu(struct task_struct *p, struct sched_domain *sd, bool */ this_rq->wake_avg_idle -= min(this_rq->wake_avg_idle, time); - update_avg(&this_sd->avg_scan_cost, time); + update_avg(&sd->avg_scan_cost, time); } return idle_cpu; -- 2.33.0
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