From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932579Ab0JOUMw (ORCPT ); Fri, 15 Oct 2010 16:12:52 -0400 Received: from smtp-out.google.com ([216.239.44.51]:43313 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932472Ab0JOUMs (ORCPT ); Fri, 15 Oct 2010 16:12:48 -0400 DomainKey-Signature: a=rsa-sha1; s=beta; d=google.com; c=nofws; q=dns; h=from:to:cc:subject:date:message-id:x-mailer:in-reply-to:references; b=PLU9KPVMxAA/wQzh2oqgFm+XHoOyFQzPssyq+86bXH3KwbU9igjDYHYQW8lpI+u15 YGKiSVgNE4reqfP7VVenQ== From: Nikhil Rao To: Ingo Molnar , Peter Zijlstra , Mike Galbraith , Suresh Siddha , Venkatesh Pallipadi Cc: linux-kernel@vger.kernel.org, Satoru Takeuchi , Nikhil Rao Subject: [PATCH 1/4] sched: do not consider SCHED_IDLE tasks to be cache hot Date: Fri, 15 Oct 2010 13:12:27 -0700 Message-Id: <1287173550-30365-2-git-send-email-ncrao@google.com> X-Mailer: git-send-email 1.7.1 In-Reply-To: <1287173550-30365-1-git-send-email-ncrao@google.com> References: <1287173550-30365-1-git-send-email-ncrao@google.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This patch adds a check in task_hot to return if the task has SCHED_IDLE policy. SCHED_IDLE tasks have very low weight, and when run with regular workloads, are typically scheduled many milliseconds apart. There is no need to consider these tasks hot for load balancing. Signed-off-by: Nikhil Rao --- kernel/sched.c | 3 +++ 1 files changed, 3 insertions(+), 0 deletions(-) diff --git a/kernel/sched.c b/kernel/sched.c index dc85ceb..9e01848 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -2003,6 +2003,9 @@ task_hot(struct task_struct *p, u64 now, struct sched_domain *sd) if (p->sched_class != &fair_sched_class) return 0; + if (unlikely(p->policy == SCHED_IDLE)) + return 0; + /* * Buddy candidates are cache hot: */ -- 1.7.1