From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932339AbdGJRLZ (ORCPT ); Mon, 10 Jul 2017 13:11:25 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:46574 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932097AbdGJRLW (ORCPT ); Mon, 10 Jul 2017 13:11:22 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jirka Hladky , Rik van Riel , Linus Torvalds , Mel Gorman , Mike Galbraith , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Mel Gorman Subject: [PATCH 4.12 21/27] sched/numa: Override part of migrate_degrades_locality() when idle balancing Date: Mon, 10 Jul 2017 19:10:18 +0200 Message-Id: <20170710170104.777631942@linuxfoundation.org> X-Mailer: git-send-email 2.13.2 In-Reply-To: <20170710170103.831324799@linuxfoundation.org> References: <20170710170103.831324799@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Rik van Riel 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 Signed-off-by: Rik van Riel Cc: Linus Torvalds Cc: Mel Gorman Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/r/20170623165530.22514-2-riel@redhat.com Signed-off-by: Ingo Molnar Signed-off-by: Mel Gorman Signed-off-by: Greg Kroah-Hartman --- kernel/sched/fair.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -6661,6 +6661,10 @@ static int migrate_degrades_locality(str 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);