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
next prev 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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