Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752155AbYLQSqo (ORCPT ); Wed, 17 Dec 2008 13:46:44 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751438AbYLQSqW (ORCPT ); Wed, 17 Dec 2008 13:46:22 -0500 Received: from e28smtp05.in.ibm.com ([59.145.155.5]:53745 "EHLO e28smtp05.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751380AbYLQSqV (ORCPT ); Wed, 17 Dec 2008 13:46:21 -0500 Date: Wed, 17 Dec 2008 23:39:32 +0530 From: Balbir Singh To: Vaidyanathan Srinivasan Cc: Linux Kernel , Suresh B Siddha , Venkatesh Pallipadi , Peter Zijlstra , Ingo Molnar , Dipankar Sarma , Vatsa , Gautham R Shenoy , Andi Kleen , David Collier-Brown , Tim Connors , Max Krasnyansky , Gregory Haskins , Pavel Machek Subject: Re: [PATCH v6 2/7] sched: favour lower logical cpu number for sched_mc balance Message-ID: <20081217180932.GB26572@balbir.in.ibm.com> Reply-To: balbir@linux.vnet.ibm.com Mail-Followup-To: Vaidyanathan Srinivasan , Linux Kernel , Suresh B Siddha , Venkatesh Pallipadi , Peter Zijlstra , Ingo Molnar , Dipankar Sarma , Vatsa , Gautham R Shenoy , Andi Kleen , David Collier-Brown , Tim Connors , Max Krasnyansky , Gregory Haskins , Pavel Machek References: <20081217172309.534.28847.stgit@drishya.in.ibm.com> <20081217172642.534.10983.stgit@drishya.in.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <20081217172642.534.10983.stgit@drishya.in.ibm.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Vaidyanathan Srinivasan [2008-12-17 22:56:42]: > 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 16897ab..0b9bbbd 100644 > --- a/kernel/sched.c > +++ b/kernel/sched.c > @@ -3264,7 +3264,7 @@ 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; > @@ -3280,7 +3280,7 @@ 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; > > OK, so group_min is pushed to higher cpu numbers and group_leader is pulled to lower cpu numbers Acked-by: Balbir Singh -- Balbir -- 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/