From: riel@redhat.com
To: linux-kernel@vger.kernel.org
Cc: jhladky@redhat.com, mingo@kernel.org, mgorman@suse.de,
peterz@infradead.org
Subject: [PATCH 2/4] sched: simplify wake_affine for single socket case
Date: Fri, 23 Jun 2017 12:55:28 -0400 [thread overview]
Message-ID: <20170623165530.22514-3-riel@redhat.com> (raw)
In-Reply-To: <20170623165530.22514-1-riel@redhat.com>
From: Rik van Riel <riel@redhat.com>
Then this_cpu and prev_cpu are in the same socket, select_idle_sibling
will do its thing regardless of the return value of wake_affine. Just
return true and don't look at all the other things.
Signed-off-by: Rik van Riel <riel@redhat.com>
---
kernel/sched/fair.c | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 2180c8591e16..949de24e36bd 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -5373,6 +5373,13 @@ static int wake_affine(struct sched_domain *sd, struct task_struct *p,
this_load = target_load(this_cpu, idx);
/*
+ * Common case: CPUs are in the same socket, and select_idle_sibling
+ * will do its thing regardless of what we return.
+ */
+ if (cpus_share_cache(prev_cpu, this_cpu))
+ return true;
+
+ /*
* If sync wakeup then subtract the (maximum possible)
* effect of the currently running task from the load
* of the current CPU:
@@ -5960,11 +5967,15 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int sd_flag, int wake_f
if (affine_sd) {
sd = NULL; /* Prefer wake_affine over balance flags */
- if (cpu != prev_cpu && wake_affine(affine_sd, p, prev_cpu, sync))
+ if (cpu == prev_cpu)
+ goto pick_cpu;
+
+ if (wake_affine(affine_sd, p, prev_cpu, sync))
new_cpu = cpu;
}
if (!sd) {
+ pick_cpu:
if (sd_flag & SD_BALANCE_WAKE) /* XXX always ? */
new_cpu = select_idle_sibling(p, prev_cpu, new_cpu);
--
2.9.4
next prev parent reply other threads:[~2017-06-23 16:55 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-23 16:55 [PATCH 0/4] NUMA improvements with task wakeup and load balancing riel
2017-06-23 16:55 ` [PATCH 1/4] sched,numa: override part of migrate_degrades_locality when idle balancing riel
2017-06-24 6:58 ` Ingo Molnar
2017-06-24 23:45 ` Rik van Riel
2017-06-24 7:22 ` [tip:sched/core] sched/numa: Override part of migrate_degrades_locality() " tip-bot for Rik van Riel
2017-06-23 16:55 ` riel [this message]
2017-06-24 7:22 ` [tip:sched/core] sched/fair: Simplify wake_affine() for the single socket case tip-bot for Rik van Riel
2017-06-23 16:55 ` [PATCH 3/4] sched,numa: implement numa node level wake_affine riel
2017-06-24 7:23 ` [tip:sched/core] sched/numa: Implement NUMA node level wake_affine() tip-bot for Rik van Riel
2017-06-26 14:43 ` [PATCH 3/4] sched,numa: implement numa node level wake_affine Peter Zijlstra
2017-06-23 16:55 ` [PATCH 4/4] sched,fair: remove effective_load riel
2017-06-24 7:23 ` [tip:sched/core] sched/fair: Remove effective_load() tip-bot for Rik van Riel
2017-06-26 14:44 ` [PATCH 4/4] sched,fair: remove effective_load Peter Zijlstra
2017-06-26 14:46 ` Peter Zijlstra
2017-06-26 14:55 ` Rik van Riel
2017-06-26 15:04 ` Peter Zijlstra
2017-06-26 15:20 ` Rik van Riel
2017-06-26 16:12 ` Peter Zijlstra
2017-06-26 19:34 ` Rik van Riel
2017-06-27 5:39 ` Peter Zijlstra
2017-06-27 14:55 ` Rik van Riel
2017-08-01 12:19 ` [PATCH] sched/fair: Fix wake_affine() for !NUMA_BALANCING Peter Zijlstra
2017-08-01 19:26 ` Josef Bacik
2017-08-01 21:43 ` Peter Zijlstra
2017-08-24 22:29 ` Chris Wilson
2017-08-25 15:46 ` Chris Wilson
2017-06-27 18:27 ` [PATCH 4/4] sched,fair: remove effective_load Rik van Riel
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