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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8081BEB64DD for ; Mon, 14 Aug 2023 18:34:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231543AbjHNSdf (ORCPT ); Mon, 14 Aug 2023 14:33:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48858 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229788AbjHNSdC (ORCPT ); Mon, 14 Aug 2023 14:33:02 -0400 Received: from mail-ed1-x529.google.com (mail-ed1-x529.google.com [IPv6:2a00:1450:4864:20::529]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 15A45E63 for ; Mon, 14 Aug 2023 11:32:58 -0700 (PDT) Received: by mail-ed1-x529.google.com with SMTP id 4fb4d7f45d1cf-522ab557632so6267347a12.0 for ; Mon, 14 Aug 2023 11:32:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1692037976; x=1692642776; h=content-transfer-encoding:mime-version:user-agent:references :in-reply-to:date:cc:to:from:subject:message-id:from:to:cc:subject :date:message-id:reply-to; bh=+BpmMd9DCnNsopJ62AvbT/bgZJHPIb6r70TIq9xOz8E=; b=Uymj+6di+pNNTu6K6E9TRQrnWfY6YEMmKLn3RgGCY/elyt1ebNb7U4/n4r4sckrxJr pAKXkdsHdhRC2+RIsPCBKj7SWg1gQOKLBSozY+fw+hARWvaqT72whad9h9Sd6f0nQdJu QiXkxqT9mKKoKXv24fV/eNOYbmu067ZnnyyGMF6OCfRpuCT9d52kbq0XhfzSjyWomYtd t6JjReEjkYwuGHlzoynobG5SDN8S2bMcFSMLbI0HxaDg1pBbKi9tx+fK3FJsC6ek6j/T Egc06shIdY7Z6uYHO43nqnMZRMyp3q44A1vCjtWuOKvJ7EVN7AK6AgYMmrWq1bbdtsG1 Zr5A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1692037976; x=1692642776; h=content-transfer-encoding:mime-version:user-agent:references :in-reply-to:date:cc:to:from:subject:message-id:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=+BpmMd9DCnNsopJ62AvbT/bgZJHPIb6r70TIq9xOz8E=; b=VyC3wr1Abjkwuk0E+PUxoNjDuAkMCMOUU582LC9U82cXx+HaMXvexjKXejrh4HpMDX 15CmMw9vM0g8Udu3g4w0KiVVl3oFq1LyPMbIAjQS7iI+a9/QvRkqxA/1fnSAUraeM253 fS/JRsmaT8odoYKdETPir2wwy6WDhtIRp6+cIuK8gmCq+VacO42F2pk193KMfcsz1t83 y9vHbE8GUpaUaf7BxfC3dqCQX3TQpnVb/jrn2JWACuFursAWyCRBO6oPThBIDfE5hTjK wvu3+P8ULmAxKS2mkjqdhKShxR2sndq8yrIA7kogu6hN6idD7EjEEaj1V/UFIu3LHi3m LPIA== X-Gm-Message-State: AOJu0Yx6W+H3JPIwAkdBlsE11CRuYKeZhAf6oR3gFsAC520vl0CZPPqF li3BcUDweYO12oSVQwwxFDF6e8HeJ/p/2g== X-Google-Smtp-Source: AGHT+IGzZzTr/nhp1QdpwulYBBSdiz7yl56tPp2xbyf/XIkeFmv9llvKhhlwYtFrPyIuGyjfNh5f9w== X-Received: by 2002:aa7:da06:0:b0:525:69ec:e1c8 with SMTP id r6-20020aa7da06000000b0052569ece1c8mr1858219eds.40.1692037976312; Mon, 14 Aug 2023 11:32:56 -0700 (PDT) Received: from homer.fritz.box ([185.221.151.76]) by smtp.googlemail.com with ESMTPSA id f10-20020a056402150a00b00525727db542sm104045edw.54.2023.08.14.11.32.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 14 Aug 2023 11:32:56 -0700 (PDT) Message-ID: Subject: Re: [tip:sched/eevdf] [sched/fair] e0c2ff903c: phoronix-test-suite.blogbench.Write.final_score -34.8% regression From: Mike Galbraith To: Peter Zijlstra , Chen Yu Cc: kernel test robot , oe-lkp@lists.linux.dev, lkp@intel.com, linux-kernel@vger.kernel.org, x86@kernel.org, Ingo Molnar Date: Mon, 14 Aug 2023 20:32:55 +0200 In-Reply-To: <20230814132935.GK776869@hirez.programming.kicks-ass.net> References: <202308101628.7af4631a-oliver.sang@intel.com> <20230814132935.GK776869@hirez.programming.kicks-ass.net> Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.42.4 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2023-08-14 at 15:29 +0200, Peter Zijlstra wrote: > > --- > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index fe5be91c71c7..16d24e5dda8f 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -8047,6 +8047,15 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_ >         cfs_rq = cfs_rq_of(se); >         update_curr(cfs_rq); >   > +       if (sched_feat(WAKEUP_DEADLINE)) { > +               /* > +                * Only allow preemption if the virtual deadline of the new > +                * task is before the virtual deadline of the existing task. > +                */ > +               if (deadline_gt(deadline, pse, se)) > +                       return; > +       } > + >         /* >          * XXX pick_eevdf(cfs_rq) != se ? >          */ > diff --git a/kernel/sched/features.h b/kernel/sched/features.h > index 61bcbf5e46a4..e733981b32aa 100644 > --- a/kernel/sched/features.h > +++ b/kernel/sched/features.h > @@ -24,6 +24,7 @@ SCHED_FEAT(CACHE_HOT_BUDDY, true) >   * Allow wakeup-time preemption of the current task: >   */ >  SCHED_FEAT(WAKEUP_PREEMPTION, true) > +SCHED_FEAT(WAKEUP_DEADLINE, true) >   >  SCHED_FEAT(HRTICK, false) >  SCHED_FEAT(HRTICK_DL, false) I don't have that phoronix thingy, but the above didn't seem to do anything for hackbench here. I whack eevdf with the stick below to dampen its scheduling enthusiasm a little, and it did help the hackbench deficit some. (yup, it's all rob Peter to pay Paul.. this game has no winner:) hackbench -l 10000 avg 6.4.10-cfs 5.575 5.565 5.575 5.571 v cfs 6.4.10-eevdf 6.106 6.078 6.103 6.095 1.094 5.888 5.890 5.889 5.889 1.057 +RUN_TO_PARITY --- kernel/sched/fair.c | 6 ++++++ kernel/sched/features.h | 1 + 2 files changed, 7 insertions(+) --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -875,6 +875,12 @@ static struct sched_entity *pick_eevdf(s if (curr && (!curr->on_rq || !entity_eligible(cfs_rq, curr))) curr = NULL; + /* + * Once selected, run the task to parity to avoid overscheduling. + */ + if (sched_feat(RUN_TO_PARITY) && curr) + return curr; + while (node) { struct sched_entity *se = __node_2_se(node); --- a/kernel/sched/features.h +++ b/kernel/sched/features.h @@ -7,6 +7,7 @@ SCHED_FEAT(PLACE_LAG, true) SCHED_FEAT(PLACE_FUDGE, true) SCHED_FEAT(PLACE_DEADLINE_INITIAL, true) +SCHED_FEAT(RUN_TO_PARITY, true) /* * Prefer to schedule the task we woke last (assuming it failed