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From: subhra mazumdar <subhra.mazumdar@oracle.com>
To: linux-kernel@vger.kernel.org
Cc: peterz@infradead.org, mingo@redhat.com,
	steven.sistare@oracle.com, dhaval.giani@oracle.com,
	daniel.lezcano@linaro.org, vincent.guittot@linaro.org,
	viresh.kumar@linaro.org, tim.c.chen@linux.intel.com,
	mgorman@techsingularity.net
Subject: [PATCH v3 7/7] sched: use per-cpu variable cpumask_weight_sibling
Date: Sat,  8 Jun 2019 18:49:54 -0700	[thread overview]
Message-ID: <20190609014954.1033-8-subhra.mazumdar@oracle.com> (raw)
In-Reply-To: <20190609014954.1033-1-subhra.mazumdar@oracle.com>

Use per-cpu var cpumask_weight_sibling for quick lookup in select_idle_cpu.
This is the fast path of scheduler and every cycle is worth saving. Usage
of cpumask_weight can result in iterations.

Signed-off-by: subhra mazumdar <subhra.mazumdar@oracle.com>
---
 kernel/sched/fair.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 6a74808..878f11c 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -6206,7 +6206,7 @@ static int select_idle_cpu(struct task_struct *p, struct sched_domain *sd, int t
 
 	if (sched_feat(SIS_PROP)) {
 		u64 span_avg = sd->span_weight * avg_idle;
-		floor = cpumask_weight(topology_sibling_cpumask(target));
+		floor = topology_sibling_weight(target);
 		if (floor < 2)
 			floor = 2;
 		limit = floor << 1;
-- 
2.9.3


  parent reply	other threads:[~2019-06-09  1:55 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-09  1:49 [PATCH v3 0/7] Improve scheduler scalability for fast path subhra mazumdar
2019-06-09  1:49 ` [PATCH v3 1/7] sched: limit cpu search in select_idle_cpu subhra mazumdar
2019-06-09  1:49 ` [PATCH v3 2/7] sched: introduce per-cpu var next_cpu to track search limit subhra mazumdar
2019-06-09  1:49 ` [PATCH v3 3/7] sched: rotate the cpu search window for better spread subhra mazumdar
2019-06-09  1:49 ` [PATCH v3 4/7] sched: add sched feature to disable idle core search subhra mazumdar
2019-06-09  1:49 ` [PATCH v3 5/7] sched: SIS_CORE " subhra mazumdar
2019-06-09  1:49 ` [PATCH v3 6/7] x86/smpboot: introduce per-cpu variable for HT siblings subhra mazumdar
2019-06-09  1:49 ` subhra mazumdar [this message]
2019-06-27  1:29 [RESEND PATCH v3 0/7] Improve scheduler scalability for fast path subhra mazumdar
2019-06-27  1:29 ` [PATCH v3 7/7] sched: use per-cpu variable cpumask_weight_sibling subhra mazumdar

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