Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753928AbaKDOTh (ORCPT ); Tue, 4 Nov 2014 09:19:37 -0500 Received: from mail-ie0-f181.google.com ([209.85.223.181]:64897 "EHLO mail-ie0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751104AbaKDOTe convert rfc822-to-8bit (ORCPT ); Tue, 4 Nov 2014 09:19:34 -0500 MIME-Version: 1.0 In-Reply-To: <5458B77F.9060007@gmail.com> References: <1415099585-31174-1-git-send-email-pang.xunlei@linaro.org> <1415099585-31174-5-git-send-email-pang.xunlei@linaro.org> <5458B77F.9060007@gmail.com> Date: Tue, 4 Nov 2014 22:19:33 +0800 Message-ID: Subject: Re: [PATCH v2 5/6] sched/dl: Optimize select_task_rq_dl() for non-DL curr task From: "pang.xunlei" To: Wanpeng Li Cc: lkml , Ingo Molnar , Peter Zijlstra , Steven Rostedt , Juri Lelli Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 4 November 2014 19:24, Wanpeng Li wrote: > > On 14/11/4 下午7:13, pang.xunlei wrote: >> >> When selecting the cpu for a waking DL task, if curr is a non-DL >> task which is bound only on this cpu, then we can give it a chance >> to select a different cpu for this DL task to avoid curr starving. >> >> Signed-off-by: pang.xunlei >> --- >> kernel/sched/deadline.c | 14 ++++++++++---- >> 1 file changed, 10 insertions(+), 4 deletions(-) >> >> diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c >> index 7b0b2d2..1f64d4a 100644 >> --- a/kernel/sched/deadline.c >> +++ b/kernel/sched/deadline.c >> @@ -954,6 +954,9 @@ select_task_rq_dl(struct task_struct *p, int cpu, int >> sd_flag, int flags) >> struct task_struct *curr; >> struct rq *rq; >> + if (p->nr_cpus_allowed == 1) >> + goto out; >> + >> if (sd_flag != SD_BALANCE_WAKE && sd_flag != SD_BALANCE_FORK) >> goto out; > > > I don't think you use right branch of tip tree. Hi Wanpeng, I'm using linux-3.18-rc3 as the base, does this have something wrong? please point me out if any. Thanks! > > Regards, > Wanpeng Li > >> @@ -970,11 +973,14 @@ select_task_rq_dl(struct task_struct *p, int cpu, >> int sd_flag, int flags) >> * can!) we prefer to send it somewhere else. On the >> * other hand, if it has a shorter deadline, we >> * try to make it stay here, it might be important. >> + * >> + * If the current task on @p's runqueue is a non-DL task, >> + * and this task is bound on current runqueue, then try to >> + * see if we can wake this DL task up on a different runqueue, >> */ >> - if (unlikely(dl_task(curr)) && >> - (curr->nr_cpus_allowed < 2 || >> - !dl_entity_preempt(&p->dl, &curr->dl)) && >> - (p->nr_cpus_allowed > 1)) { >> + if (unlikely(curr->nr_cpus_allowed < 2) || >> + unlikely(dl_task(curr) && >> + !dl_entity_preempt(&p->dl, &curr->dl))) { >> int target = find_later_rq(p); >> if (target != -1) > > -- 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/