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Commit 739294fb authored by Rik van Riel's avatar Rik van Riel Committed by Ingo Molnar
Browse files

sched/numa: Override part of migrate_degrades_locality() when idle balancing 



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: default avatarJirka Hladky <jhladky@redhat.com>
Signed-off-by: default avatarRik 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: default avatarIngo Molnar <mingo@kernel.org>
parent 1bc3cd4d

kernel/sched/fair.c

+4 −0
Original line number Diff line number Diff line
@@ -6688,6 +6688,10 @@ 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);