From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID, URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 77BC8C433F5 for ; Fri, 31 Aug 2018 14:42:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 314D220839 for ; Fri, 31 Aug 2018 14:42:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="XHBGUBaa" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 314D220839 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728812AbeHaStq (ORCPT ); Fri, 31 Aug 2018 14:49:46 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:54392 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728155AbeHaStp (ORCPT ); Fri, 31 Aug 2018 14:49:45 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=MOqiY+qUkOIgh5+2M5RPTQ6GsfoDgjaZ/+YIBrUb1es=; b=XHBGUBaa9X4GQrjOtu2SnePd7 K4H/BRnbhq38Ls9cqMe64xzudCXb/76kTZu8FCqQJg4EMozjl1fmG38uHD9nKXiyLrvBgSkZC5ymx 8u9Nv/jNXOI9RdQVIFWQwiDxdO0YstMyiswspzod1wO1l/d1FK54IxOje99ZhRdpCOb1wVC+BHVct yCeQXZ7JH+Bl+b+ftyUsmEKFV2ag/nQosAclE1ol1Zw+4s1mLXtlIdq1dE+4hSe6IDeu3ARII7eaP bzgNCJojRmHTlN1JQphFj5hGgLymAA3tSiTyoMeyFamm+FR0ySoADtPu8dOnMmRB0eH756UKyw6Tc SCyM2NM9Q==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1fvkcW-0001EL-08; Fri, 31 Aug 2018 14:41:57 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 640822027215E; Fri, 31 Aug 2018 16:41:46 +0200 (CEST) Date: Fri, 31 Aug 2018 16:41:46 +0200 From: Peter Zijlstra To: Vincent Guittot Cc: mingo@redhat.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH] sched/pelt: fix update_blocked_averages() for dl and rt Message-ID: <20180831144146.GO24124@hirez.programming.kicks-ass.net> References: <1535723908-10779-1-git-send-email-vincent.guittot@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1535723908-10779-1-git-send-email-vincent.guittot@linaro.org> User-Agent: Mutt/1.10.0 (2018-05-17) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Aug 31, 2018 at 03:58:28PM +0200, Vincent Guittot wrote: > update_blocked_averages() is called to periodiccally decay the stalled load > of idle CPUs and to sync all loads before running load balance. > > When cfs rq is idle, it trigs a load balance during pick_next_task_fair() > in order to potentially pull tasks and to use this newly idle CPU. This > load balance happens whereas prev task from another class has not been put > and its utilization updated yet. This may lead to wrongly account running > time as idle time for rt or dl classes. > > Test that no rt or dl task is running when updating their utilization in > update_blocked_averages(). > > We still update rt and dl utilization instead of simply skipping them to > make sure that all metrics are synced when used during load balance. > Fixes: 371bf4273269 ("sched/rt: Add rt_rq utilization tracking") Fixes: 3727e0e16340 ("sched/dl: Add dl_rq utilization tracking") Right? > Signed-off-by: Vincent Guittot > --- > kernel/sched/fair.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index 309c93f..a1babaf 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -7262,6 +7262,7 @@ static void update_blocked_averages(int cpu) > { > struct rq *rq = cpu_rq(cpu); > struct cfs_rq *cfs_rq, *pos; > + const struct sched_class *curr_class = rq->curr->sched_class; > struct rq_flags rf; > bool done = true; > > @@ -7298,8 +7299,8 @@ static void update_blocked_averages(int cpu) > if (cfs_rq_has_blocked(cfs_rq)) > done = false; > } > - update_rt_rq_load_avg(rq_clock_task(rq), rq, 0); > - update_dl_rq_load_avg(rq_clock_task(rq), rq, 0); > + update_rt_rq_load_avg(rq_clock_task(rq), rq, curr_class == &rt_sched_class); > + update_dl_rq_load_avg(rq_clock_task(rq), rq, curr_class == &dl_sched_class); > update_irq_load_avg(rq, 0); > /* Don't need periodic decay once load/util_avg are null */ > if (others_have_blocked(rq)) Did you forget to update the second implementation of update_blocked_averages() ?