From: Mel Gorman <mgorman@techsingularity.net>
To: Linux-Stable <stable@vger.kernel.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Subject: [PATCH 5/9] sched/numa: Override part of migrate_degrades_locality() when idle balancing
Date: Mon, 10 Jul 2017 13:37:48 +0100 [thread overview]
Message-ID: <20170710123752.7563-6-mgorman@techsingularity.net> (raw)
In-Reply-To: <20170710123752.7563-1-mgorman@techsingularity.net>
From: Rik van Riel <riel@redhat.com>
commit 739294fb03f590401bbd7faa6d31a507e3ffada5 upstream.
Several tests in the NAS benchmark seem to run a lot slower with
NUMA balancing enabled, than with NUMA balancing disabled. The
slower run time corresponds with increased idle time.
Overriding the final test of migrate_degrades_locality (but still
doing the other NUMA tests first) seems to improve performance
of those benchmarks.
Reported-by: Jirka Hladky <jhladky@redhat.com>
Signed-off-by: Rik van Riel <riel@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/20170623165530.22514-2-riel@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
---
kernel/sched/fair.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 85ed4d2df424..bbf45ed4a370 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -6687,6 +6687,10 @@ static int migrate_degrades_locality(struct task_struct *p, struct lb_env *env)
if (dst_nid == p->numa_preferred_nid)
return 0;
+ /* Leaving a core idle is often worse than degrading locality. */
+ if (env->idle != CPU_NOT_IDLE)
+ return -1;
+
if (numa_group) {
src_faults = group_faults(p, src_nid);
dst_faults = group_faults(p, dst_nid);
--
2.13.1
next prev parent reply other threads:[~2017-07-10 12:43 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-10 12:37 [PATCH 0/9] Performance-related backports for 4.12 Mel Gorman
2017-07-10 12:37 ` [PATCH 1/9] x86/uaccess: Optimize copy_user_enhanced_fast_string() for short strings Mel Gorman
2017-07-10 12:37 ` [PATCH 2/9] sched/fair, cpumask: Export for_each_cpu_wrap() Mel Gorman
2017-07-10 12:37 ` [PATCH 3/9] sched/core: Implement new approach to scale select_idle_cpu() Mel Gorman
2017-07-10 12:37 ` [PATCH 4/9] sched/numa: Use down_read_trylock() for the mmap_sem Mel Gorman
2017-07-10 12:37 ` Mel Gorman [this message]
2017-07-10 12:37 ` [PATCH 6/9] sched/fair: Simplify wake_affine() for the single socket case Mel Gorman
2017-07-10 12:37 ` [PATCH 7/9] sched/numa: Implement NUMA node level wake_affine() Mel Gorman
2017-07-10 12:37 ` [PATCH 8/9] sched/fair: Remove effective_load() Mel Gorman
2017-07-10 12:37 ` [PATCH 9/9] sched/numa: Hide numa_wake_affine() from UP build Mel Gorman
2017-07-10 15:25 ` [PATCH 0/9] Performance-related backports for 4.12 Greg KH
2017-07-10 15:32 ` Mel Gorman
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