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=-9.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 4E6FEC433E1 for ; Thu, 20 Aug 2020 14:16:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2A93C20674 for ; Thu, 20 Aug 2020 14:16:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="WbrhuEOS" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727785AbgHTOQR (ORCPT ); Thu, 20 Aug 2020 10:16:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44860 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727104AbgHTOQK (ORCPT ); Thu, 20 Aug 2020 10:16:10 -0400 Received: from mail-ot1-x344.google.com (mail-ot1-x344.google.com [IPv6:2607:f8b0:4864:20::344]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 82DB4C061385 for ; Thu, 20 Aug 2020 07:16:10 -0700 (PDT) Received: by mail-ot1-x344.google.com with SMTP id 93so1575915otx.2 for ; Thu, 20 Aug 2020 07:16:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=B+J7lomXgLWNuigG3s6WQmeUx7fd4tzzG7fep5GXpWg=; b=WbrhuEOSwzQ0ObGN6ndI+J0+7iTyfNthtQmgj+fnMQADnHHK3EPfetHC5BUhedeKPH Y+hfciCpC4WmXkhwhQwJD7zhOYw6Rgy4UPQyjDiIHHCbm6/LZR67casnXVlDPtSolXkf LmolHZcKRMZxk1Dh7gcPAwYVXC+akqCuYFlIaq/7kBVz+CLFgDG/VI+C7DuB5RtkUT0d rumxxRq1ctpPnL1UXaR5CR7LaNo70qzCxLERpnuJ0u5D3pnZyy7psjon5x3Svql6w0uQ R43abRN1sfpJN/pbJKs5o+d8s4OgkOWTvf6z9H47bzkykLrCEfS8EaSX+2A8o5/FHTLB k+rA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=B+J7lomXgLWNuigG3s6WQmeUx7fd4tzzG7fep5GXpWg=; b=KY2wXpsdmowJt/UQYqTV7yemE2tIgGnJ5xmhU7SMv2kjKmPS21VLbljyhmBsdyd3yY KdvlSlDUbDl786KY6LoNwmmaYOY51P72zK5NC6eMVIJSYO8qPaXagiL7ZHmRp43dKx0h xI3jn4MEf1r3CnFfpFUpzbPNlZn/YpgRGs7vkAmF8QcPc7mOtpg4zaOThnDHCRps8Eji X8i7b03zyIEro48OXut6TafhSTsh851GbM/BQqQN/ReWpjj+Dp4QPQp5LBS4Sh01QXlr 0WnAEhRtE5cOcWZ1epHtSxELrUjMmebPsnRl1keM4OSp5356oIbDSbAyUCSnuajafuNz AJng== X-Gm-Message-State: AOAM531cjGkAtCcJkxotIy7Nuu0YFf4V49ncmaiABsObP9qboZt4Paip dgSKr6rSIGu33knphruJcFi9HQ4QSdl9g7pn5SQ= X-Google-Smtp-Source: ABdhPJyjc3/KwaQUMUvpqjECzPLWZFAanHrS3/z6f9rfWU56q1DncZ7INMgLPG7Ho1ujeFYaffDBCFT4H+W2wNT8wDQ= X-Received: by 2002:a9d:6b0c:: with SMTP id g12mr2426931otp.4.1597932969941; Thu, 20 Aug 2020 07:16:09 -0700 (PDT) MIME-Version: 1.0 References: <20200820120025.74460-1-benbjiang@tencent.com> In-Reply-To: From: Jiang Biao Date: Thu, 20 Aug 2020 22:15:59 +0800 Message-ID: Subject: Re: [PATCH] sched/fair: avoid vruntime compensation for SCHED_IDLE task To: Vincent Guittot Cc: Ingo Molnar , Peter Zijlstra , Juri Lelli , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , linux-kernel , Jiang Biao Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 20 Aug 2020 at 20:51, Vincent Guittot wrote: > > On Thu, 20 Aug 2020 at 14:00, Jiang Biao wrote: > > > > From: Jiang Biao > > > > Vruntime compensation has been down in place_entity() to > > boot the waking procedure for fair tasks. There is no need to > > s/boot/boost/ ? Yes. -:) > > > do that for SCHED_IDLE task actually. > > > > Not compensating vruntime for SCHED_IDLE task could make > > SCHED_IDLE task more harmless for normal tasks. > > > > Signed-off-by: Jiang Biao > > --- > > kernel/sched/fair.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > > index 1a68a0536add..adff77676a0a 100644 > > --- a/kernel/sched/fair.c > > +++ b/kernel/sched/fair.c > > @@ -4115,7 +4115,7 @@ place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int initial) > > vruntime += sched_vslice(cfs_rq, se); > > > > /* sleeps up to a single latency don't count. */ > > - if (!initial) { > > + if (!initial && likely(!task_has_idle_policy(task_of(se)))) { > > What if se is not a task ? Is it ok to limit the case to task se, like? + if (!initial && likely(!entity_is_task(se) || !task_has_idle_policy(task_of(se)))) { Thx. Regards, Jiang > > > unsigned long thresh = sysctl_sched_latency; > > > > /* > > -- > > 2.21.0 > >