Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756938Ab2J2N15 (ORCPT ); Mon, 29 Oct 2012 09:27:57 -0400 Received: from mail-la0-f46.google.com ([209.85.215.46]:42672 "EHLO mail-la0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754795Ab2J2N14 (ORCPT ); Mon, 29 Oct 2012 09:27:56 -0400 MIME-Version: 1.0 In-Reply-To: <50880774.5090605@ti.com> References: <1349595838-31274-1-git-send-email-vincent.guittot@linaro.org> <1349595838-31274-6-git-send-email-vincent.guittot@linaro.org> <50880774.5090605@ti.com> Date: Mon, 29 Oct 2012 14:27:54 +0100 Message-ID: Subject: Re: [RFC 5/6] sched: pack the idle load balance From: Vincent Guittot To: Santosh Shilimkar Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linaro-dev@lists.linaro.org, peterz@infradead.org, mingo@redhat.com, pjt@google.com, linux@arm.linux.org.uk Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2212 Lines: 70 On 24 October 2012 17:21, Santosh Shilimkar wrote: > On Sunday 07 October 2012 01:13 PM, Vincent Guittot wrote: >> >> Look for an idle CPU close the pack buddy CPU whenever possible. > > s/close/close to yes > >> The goal is to prevent the wake up of a CPU which doesn't share the power >> line of the pack CPU >> >> Signed-off-by: Vincent Guittot >> --- >> kernel/sched/fair.c | 18 ++++++++++++++++++ >> 1 file changed, 18 insertions(+) >> >> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c >> index 6df53b5..f76acdc 100644 >> --- a/kernel/sched/fair.c >> +++ b/kernel/sched/fair.c >> @@ -5158,7 +5158,25 @@ static struct { >> >> static inline int find_new_ilb(int call_cpu) >> { >> + struct sched_domain *sd; >> int ilb = cpumask_first(nohz.idle_cpus_mask); >> + int buddy = per_cpu(sd_pack_buddy, call_cpu); >> + >> + /* >> + * If we have a pack buddy CPU, we try to run load balance on a >> CPU >> + * that is close to the buddy. >> + */ >> + if (buddy != -1) >> + for_each_domain(buddy, sd) { >> + if (sd->flags & SD_SHARE_CPUPOWER) >> + continue; > > Do you mean SD_SHARE_POWERLINE here ? No, I just don't want to take hyperthread level for ILB > >> + >> + ilb = cpumask_first_and(sched_domain_span(sd), >> + nohz.idle_cpus_mask); >> + >> + if (ilb < nr_cpu_ids) >> + break; >> + } >> >> if (ilb < nr_cpu_ids && idle_cpu(ilb)) >> return ilb; >> > Can you please expand "idle CPU _close_ the pack buddy CPU" ? The goal is to packed the tasks on the pack buddy CPU so when the scheduler needs to start ILB, I try to wake up a CPU that is close to the buddy and preferably in the same cluster > > Regards > santosh -- 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/