From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753475AbaHLOyP (ORCPT ); Tue, 12 Aug 2014 10:54:15 -0400 Received: from terminus.zytor.com ([198.137.202.10]:37039 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753050AbaHLOyJ (ORCPT ); Tue, 12 Aug 2014 10:54:09 -0400 Date: Tue, 12 Aug 2014 07:53:18 -0700 From: tip-bot for Rik van Riel Message-ID: Cc: linux-kernel@vger.kernel.org, riel@redhat.com, hpa@zytor.com, mingo@kernel.org, torvalds@linux-foundation.org, peterz@infradead.org, tglx@linutronix.de Reply-To: mingo@kernel.org, hpa@zytor.com, riel@redhat.com, linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, peterz@infradead.org, tglx@linutronix.de In-Reply-To: <1407173008-9334-3-git-send-email-riel@redhat.com> References: <1407173008-9334-3-git-send-email-riel@redhat.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:sched/core] sched/numa: Fix numa capacity computation Git-Commit-ID: 83d7f2424741c9dc76c21377c9d00d47abaf88df X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 83d7f2424741c9dc76c21377c9d00d47abaf88df Gitweb: http://git.kernel.org/tip/83d7f2424741c9dc76c21377c9d00d47abaf88df Author: Rik van Riel AuthorDate: Mon, 4 Aug 2014 13:23:28 -0400 Committer: Ingo Molnar CommitDate: Tue, 12 Aug 2014 12:48:23 +0200 sched/numa: Fix numa capacity computation Commit c61037e9 fixes the phenomenon of 'fantom' cores due to N*frac(smt_power) >= 1 by limiting the capacity to the actual number of cores in the load balancing code. This patch applies the same correction to the NUMA balancing code. Signed-off-by: Rik van Riel Signed-off-by: Peter Zijlstra Cc: mgorman@suse.de Cc: vincent.guittot@linaro.org Cc: Morten.Rasmussen@arm.com Cc: nicolas.pitre@linaro.org Cc: efault@gmx.de Cc: Linus Torvalds Link: http://lkml.kernel.org/r/1407173008-9334-3-git-send-email-riel@redhat.com Signed-off-by: Ingo Molnar --- kernel/sched/fair.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index e1cf419..1413c44 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -1038,7 +1038,8 @@ struct numa_stats { */ static void update_numa_stats(struct numa_stats *ns, int nid) { - int cpu, cpus = 0; + int smt, cpu, cpus = 0; + unsigned long capacity; memset(ns, 0, sizeof(*ns)); for_each_cpu(cpu, cpumask_of_node(nid)) { @@ -1062,8 +1063,12 @@ static void update_numa_stats(struct numa_stats *ns, int nid) if (!cpus) return; - ns->task_capacity = - DIV_ROUND_CLOSEST(ns->compute_capacity, SCHED_CAPACITY_SCALE); + /* smt := ceil(cpus / capacity), assumes: 1 < smt_power < 2 */ + smt = DIV_ROUND_UP(SCHED_CAPACITY_SCALE * cpus, ns->compute_capacity); + capacity = cpus / smt; /* cores */ + + ns->task_capacity = min_t(unsigned, capacity, + DIV_ROUND_CLOSEST(ns->compute_capacity, SCHED_CAPACITY_SCALE)); ns->has_free_capacity = (ns->nr_running < ns->task_capacity); }