Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755634AbYKJS3o (ORCPT ); Mon, 10 Nov 2008 13:29:44 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754150AbYKJS3g (ORCPT ); Mon, 10 Nov 2008 13:29:36 -0500 Received: from E23SMTP02.au.ibm.com ([202.81.18.163]:48580 "EHLO e23smtp02.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753859AbYKJS3f (ORCPT ); Mon, 10 Nov 2008 13:29:35 -0500 From: Vaidyanathan Srinivasan Subject: [RFC PATCH v3 2/5] sched: favour lower logical cpu number for sched_mc balance To: Linux Kernel , Suresh B Siddha , Venkatesh Pallipadi , Peter Zijlstra Cc: Ingo Molnar , Dipankar Sarma , Balbir Singh , Vatsa , Gautham R Shenoy , Andi Kleen , David Collier-Brown , Tim Connors , Max Krasnyansky , Vaidyanathan Srinivasan Date: Tue, 11 Nov 2008 00:03:16 +0530 Message-ID: <20081110183316.562.88128.stgit@drishya.in.ibm.com> In-Reply-To: <20081110181526.562.69941.stgit@drishya.in.ibm.com> References: <20081110181526.562.69941.stgit@drishya.in.ibm.com> User-Agent: StGIT/0.14.2 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1823 Lines: 44 Just in case two groups have identical load, prefer to move load to lower logical cpu number rather than the present logic of moving to higher logical number. find_busiest_group() tries to look for a group_leader that has spare capacity to take more tasks and freeup an appropriate least loaded group. Just in case there is a tie and the load is equal, then the group with higher logical number is favoured. This conflicts with user space irqbalance daemon that will move interrupts to lower logical number if the system utilisation is very low. Signed-off-by: Vaidyanathan Srinivasan --- kernel/sched.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/sched.c b/kernel/sched.c index 0dd6cf6..d910496 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -3251,7 +3251,7 @@ find_busiest_group(struct sched_domain *sd, int this_cpu, */ if ((sum_nr_running < min_nr_running) || (sum_nr_running == min_nr_running && - first_cpu(group->cpumask) < + first_cpu(group->cpumask) > first_cpu(group_min->cpumask))) { group_min = group; min_nr_running = sum_nr_running; @@ -3267,7 +3267,7 @@ find_busiest_group(struct sched_domain *sd, int this_cpu, if (sum_nr_running <= group_capacity - 1) { if (sum_nr_running > leader_nr_running || (sum_nr_running == leader_nr_running && - first_cpu(group->cpumask) > + first_cpu(group->cpumask) < first_cpu(group_leader->cpumask))) { group_leader = group; leader_nr_running = sum_nr_running; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/