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 27EECC4167D for ; Thu, 2 Nov 2023 06:29:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231481AbjKBG1r (ORCPT ); Thu, 2 Nov 2023 02:27:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49344 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229445AbjKBG1q (ORCPT ); Thu, 2 Nov 2023 02:27:46 -0400 Received: from mail-oa1-x2a.google.com (mail-oa1-x2a.google.com [IPv6:2001:4860:4864:20::2a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D075B10E for ; Wed, 1 Nov 2023 23:27:40 -0700 (PDT) Received: by mail-oa1-x2a.google.com with SMTP id 586e51a60fabf-1eb39505ba4so415824fac.0 for ; Wed, 01 Nov 2023 23:27:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance.com; s=google; t=1698906460; x=1699511260; darn=vger.kernel.org; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=LY97XwVS1CtIq+KDG3Zlhc+7zSRKCnoy+zEISQpH94w=; b=JUP06NMXP6Hxldb0XmGiMePUQRoulBRgVfQzQnc8G1SqcTVAyIWyviH9TPnuTipiys pd9zeKTSozhcUgoV+vZrQx578XCMZy6YeAGv5pHF9EPtfitQW/7d5TsCBdC4gQ8+m2Eo ZNZQWSffDvESw10t2w4VcZFY/dfzTmzhn6nP3WDp++2RSV5wvfDEQ9/IpVvvT6Sdg3G7 C4JJ5m0E+mmigW4rYV8y8/d8IbrpkloABM2k2LiwzdO1AtyQ/gcQjcVDIUxXxoeh8c13 Yub4eV+ZX7cpO/vUpjcaJlVRufGwgv8LwXbfyjGHKsYYFBKRXUhqKyX/LsG7Zwqa+s5H tSGw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1698906460; x=1699511260; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=LY97XwVS1CtIq+KDG3Zlhc+7zSRKCnoy+zEISQpH94w=; b=jOXnmQN8sVBRHpjcbE39gm+7ZSiu8s0AsyffmOSfaFCNRYrt3/4OxBz3PprZnz7CMS /siMQjj5dw7tkpJKwaJauqAnJjBwCfOvHzhoEj7e+4xodpxXcE5S48wnMfN/905z8Arz A/Qsb1Fqvd3Jr+SRYWeUcULLJne72b/UcRK7IlWlm347MCEtppyKMSM0KbWQFAkd59Jb aR9XsQKLAr/PkF9qWW54MkatGfSA0hBtJaj/by8TLZ+Cu2+J4V/we5Q4fNbeE5x37YT0 Zr86P3IHqJkfJQ+Y9LUWHJdtMQuQv9C7vbZoPXmybfyUTchPfqBf7am2uny6TEMZXgO4 gjOw== X-Gm-Message-State: AOJu0Yyn9XZVd1OkBwML86t+YFRD2UDRWrTQQN5YkDth02rHJCXM1wsq Zy9IvCfIqQzdntN+/Z6CX7dzyQ== X-Google-Smtp-Source: AGHT+IG98hJMMO+OCyZL9MNqsE+NsCXApl/8XzZLkj5lQvHnTKbMKo7UFt6DIoGCVB+otqD5Av2U4g== X-Received: by 2002:a05:6870:e984:b0:1d5:a58d:1317 with SMTP id r4-20020a056870e98400b001d5a58d1317mr22153161oao.10.1698906460092; Wed, 01 Nov 2023 23:27:40 -0700 (PDT) Received: from [10.84.152.223] ([203.208.167.147]) by smtp.gmail.com with ESMTPSA id k11-20020a637b4b000000b0059cc2f1b7basm800780pgn.11.2023.11.01.23.27.36 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 01 Nov 2023 23:27:39 -0700 (PDT) Message-ID: Date: Thu, 2 Nov 2023 14:27:33 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] sched/fair: Track current se's EEVDF parameters To: s921975628@gmail.com, mingo@redhat.com, peterz@infradead.org Cc: vincent.guittot@linaro.org, dietmar.eggemann@arm.com, linux-kernel@vger.kernel.org References: <20231101174446.90413-1-s921975628@gmail.com> Content-Language: en-US From: Abel Wu In-Reply-To: <20231101174446.90413-1-s921975628@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/2/23 1:44 AM, s921975628@gmail.com Wrote: > From: Yiwei Lin > > After dequeuing the current-picked scheduling entity with > `__dequeue_entity`, its contribution to the EEVDF parameters > cfs_rq->avg_vruntime and cfs_rq->avg_load are also removed. > Because these should in fact be considered for the EEVDF algorithm, > we took curr as the special case and inserted back the contributions > when requests for cfs_rq->avg_vruntime and cfs_rq->avg_load. Being 'curr' means its vruntime is increasing, so does its contribution to avg_vruntime. And you failed to explain the most important part that how to commit its contribution to avg_vruntime (specifically in update_curr()). Regards, Abel > > Functions like `entity_eligible` which is called insied a loop may > therefore recalculate these statistics repeatly and require more effort. > Instead, we could just avoid to remove these statistics from > cfs_rq->avg_vruntime and cfs_rq->avg_load directly. > > Signed-off-by: Yiwei Lin > --- > kernel/sched/fair.c | 34 +++++++--------------------------- > 1 file changed, 7 insertions(+), 27 deletions(-) > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index 876798824..d507ade09 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -655,17 +655,9 @@ void avg_vruntime_update(struct cfs_rq *cfs_rq, s64 delta) > */ > u64 avg_vruntime(struct cfs_rq *cfs_rq) > { > - struct sched_entity *curr = cfs_rq->curr; > s64 avg = cfs_rq->avg_vruntime; > long load = cfs_rq->avg_load; > > - if (curr && curr->on_rq) { > - unsigned long weight = scale_load_down(curr->load.weight); > - > - avg += entity_key(cfs_rq, curr) * weight; > - load += weight; > - } > - > if (load) { > /* sign flips effective floor / ceil */ > if (avg < 0) > @@ -722,17 +714,9 @@ static void update_entity_lag(struct cfs_rq *cfs_rq, struct sched_entity *se) > */ > int entity_eligible(struct cfs_rq *cfs_rq, struct sched_entity *se) > { > - struct sched_entity *curr = cfs_rq->curr; > s64 avg = cfs_rq->avg_vruntime; > long load = cfs_rq->avg_load; > > - if (curr && curr->on_rq) { > - unsigned long weight = scale_load_down(curr->load.weight); > - > - avg += entity_key(cfs_rq, curr) * weight; > - load += weight; > - } > - > return avg >= entity_key(cfs_rq, se) * load; > } > > @@ -821,11 +805,12 @@ static void __enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) > __entity_less, &min_deadline_cb); > } > > -static void __dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) > +static void __dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, bool on_rq) > { > rb_erase_augmented_cached(&se->run_node, &cfs_rq->tasks_timeline, > &min_deadline_cb); > - avg_vruntime_sub(cfs_rq, se); > + if (!on_rq) > + avg_vruntime_sub(cfs_rq, se); > } > > struct sched_entity *__pick_first_entity(struct cfs_rq *cfs_rq) > @@ -3675,8 +3660,7 @@ static void reweight_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, > /* commit outstanding execution time */ > if (cfs_rq->curr == se) > update_curr(cfs_rq); > - else > - avg_vruntime_sub(cfs_rq, se); > + avg_vruntime_sub(cfs_rq, se); > update_load_sub(&cfs_rq->load, se->load.weight); > } > dequeue_load_avg(cfs_rq, se); > @@ -3712,8 +3696,7 @@ static void reweight_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, > enqueue_load_avg(cfs_rq, se); > if (se->on_rq) { > update_load_add(&cfs_rq->load, se->load.weight); > - if (cfs_rq->curr != se) > - avg_vruntime_add(cfs_rq, se); > + avg_vruntime_add(cfs_rq, se); > } > } > > @@ -5023,7 +5006,6 @@ place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) > * EEVDF: placement strategy #1 / #2 > */ > if (sched_feat(PLACE_LAG) && cfs_rq->nr_running) { > - struct sched_entity *curr = cfs_rq->curr; > unsigned long load; > > lag = se->vlag; > @@ -5081,8 +5063,6 @@ place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) > * vl_i = (W + w_i)*vl'_i / W > */ > load = cfs_rq->avg_load; > - if (curr && curr->on_rq) > - load += scale_load_down(curr->load.weight); > > lag *= load + scale_load_down(se->load.weight); > if (WARN_ON_ONCE(!load)) > @@ -5229,7 +5209,7 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) > > update_entity_lag(cfs_rq, se); > if (se != cfs_rq->curr) > - __dequeue_entity(cfs_rq, se); > + __dequeue_entity(cfs_rq, se, 0); > se->on_rq = 0; > account_entity_dequeue(cfs_rq, se); > > @@ -5264,7 +5244,7 @@ set_next_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) > * runqueue. > */ > update_stats_wait_end_fair(cfs_rq, se); > - __dequeue_entity(cfs_rq, se); > + __dequeue_entity(cfs_rq, se, 1); > update_load_avg(cfs_rq, se, UPDATE_TG); > /* > * HACK, stash a copy of deadline at the point of pick in vlag,