From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 089426F2FD for ; Wed, 14 Aug 2024 07:26:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.50.34 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723620365; cv=none; b=brFiu4K4rqvs9AidWD5jlJCErdg2VHh5jUNJ+6kY95yjD29+jVvPowAJTS/8RbC3mLJ1qf1BvGbY3hj87xvfa99EOIvYG00bF5qe7UblgNZDlXH3UxiSPBU/4oDVHI7n7clsVOgi8f3Rk3nCCFlg7vq1mFlncrM8AtOzeu5/84I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723620365; c=relaxed/simple; bh=poywOuStYhUetZu/UHSF/VloBA8a4576b2vd54xGlvQ=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=QqUmFwElyulRroUFKSBT5LG5Vh6xFwDJ/U5FAT++HoFuNY/fVLyp2OLPivlx5/rR0ciWkJFKVFSwaXLU1EdQ7bKQcp+Qsia4ONxZkf0Fe8lWHeHigfOWWqID4e2NRY0C8b7h2xEjNmvKloRi0FwwWeRI5G59URXrmCQek2DJkmY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=P+HLG3Vg; arc=none smtp.client-ip=90.155.50.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="P+HLG3Vg" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.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; bh=ktl7L6T+RI2efOnQZ23lWcMkdOS4KwDH6qEDEskAmOM=; b=P+HLG3VgbJO6d9nTBqXaPC666y V8/q+MAGTvGFL/5yAHJmlfyuy4QJWZiFmoYL38PWxhOnZMfOotuWriudoxO/OxotS2Jxk5l32PyGI /v/+Zkiipcdu9sZGQeOjELNTDDyP2CbONSoK6iBrR4BCOylWKjmNgqna+HXhJypVrgo8ANJFhIA/q 9KX5cfvOd2Ochhbd11JbA0Ak2cb1ZtC9W+A9XDOb4A98HpqZF9AZA3IBA1R2owMrdmqL/2DD0GPCV /1vDxiwhCH/O0ify03uk7zz+dyb7xnUS6+t6bREOif9zaTsCcAs3R85QfGgn0VchdHt7Co2ScXDmz bf3atzeg==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.97.1 #2 (Red Hat Linux)) id 1se8OE-00000000532-0Pm7; Wed, 14 Aug 2024 07:25:50 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 8586130074E; Wed, 14 Aug 2024 09:25:48 +0200 (CEST) Date: Wed, 14 Aug 2024 09:25:48 +0200 From: Peter Zijlstra To: Valentin Schneider Cc: mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, linux-kernel@vger.kernel.org, kprateek.nayak@amd.com, wuyun.abel@bytedance.com, youssefesmat@chromium.org, tglx@linutronix.de, efault@gmx.de Subject: Re: [PATCH 19/24] sched/eevdf: Fixup PELT vs DELAYED_DEQUEUE Message-ID: <20240814072548.GB22686@noisy.programming.kicks-ass.net> References: <20240727102732.960974693@infradead.org> <20240727105030.514088302@infradead.org> <20240813221806.GB10328@noisy.programming.kicks-ass.net> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240813221806.GB10328@noisy.programming.kicks-ass.net> On Wed, Aug 14, 2024 at 12:18:07AM +0200, Peter Zijlstra wrote: > On Tue, Aug 13, 2024 at 02:43:56PM +0200, Valentin Schneider wrote: > > On 27/07/24 12:27, Peter Zijlstra wrote: > > > Note that tasks that are kept on the runqueue to burn off negative > > > lag, are not in fact runnable anymore, they'll get dequeued the moment > > > they get picked. > > > > > > As such, don't count this time towards runnable. > > > > > > Signed-off-by: Peter Zijlstra (Intel) > > > --- > > > kernel/sched/fair.c | 2 ++ > > > kernel/sched/sched.h | 6 ++++++ > > > 2 files changed, 8 insertions(+) > > > > > > --- a/kernel/sched/fair.c > > > +++ b/kernel/sched/fair.c > > > @@ -5388,6 +5388,7 @@ dequeue_entity(struct cfs_rq *cfs_rq, st > > > if (cfs_rq->next == se) > > > cfs_rq->next = NULL; > > > se->sched_delayed = 1; > > > + update_load_avg(cfs_rq, se, 0); > > > > Shouldn't this be before setting ->sched_delayed? accumulate_sum() should > > see the time delta as spent being runnable. > > > > > return false; > > > } > > > } > > > @@ -6814,6 +6815,7 @@ requeue_delayed_entity(struct sched_enti > > > } > > > > > > se->sched_delayed = 0; > > > + update_load_avg(cfs_rq, se, 0); > > > > Ditto on the ordering > > Bah, so I remember thinking about it and then I obviously go and do it > the exact wrong way around eh? Let me double check this tomorrow morning > with the brain slightly more awake :/ OK, so I went over it again and I ended up with the below diff -- which assuming I didn't make a giant mess of things *again*, I should go fold back into various other patches ... --- diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 1b15dbfb1ce5..fa8907f2c716 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -5461,14 +5461,10 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) { bool sleep = flags & DEQUEUE_SLEEP; + update_curr(cfs_rq); + if (flags & DEQUEUE_DELAYED) { - /* - * DEQUEUE_DELAYED is typically called from pick_next_entity() - * at which point we've already done update_curr() and do not - * want to do so again. - */ SCHED_WARN_ON(!se->sched_delayed); - se->sched_delayed = 0; } else { bool delay = sleep; /* @@ -5479,14 +5475,13 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) delay = false; SCHED_WARN_ON(delay && se->sched_delayed); - update_curr(cfs_rq); if (sched_feat(DELAY_DEQUEUE) && delay && !entity_eligible(cfs_rq, se)) { if (cfs_rq->next == se) cfs_rq->next = NULL; - se->sched_delayed = 1; update_load_avg(cfs_rq, se, 0); + se->sched_delayed = 1; return false; } } @@ -5536,6 +5531,12 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) if ((flags & (DEQUEUE_SAVE | DEQUEUE_MOVE)) != DEQUEUE_SAVE) update_min_vruntime(cfs_rq); + if (flags & DEQUEUE_DELAYED) { + se->sched_delayed = 0; + if (sched_feat(DELAY_ZERO) && se->vlag > 0) + se->vlag = 0; + } + if (cfs_rq->nr_running == 0) update_idle_cfs_rq_clock_pelt(cfs_rq); @@ -5611,11 +5612,6 @@ pick_next_entity(struct rq *rq, struct cfs_rq *cfs_rq) struct sched_entity *se = pick_eevdf(cfs_rq); if (se->sched_delayed) { dequeue_entities(rq, se, DEQUEUE_SLEEP | DEQUEUE_DELAYED); - SCHED_WARN_ON(se->sched_delayed); - SCHED_WARN_ON(se->on_rq); - if (sched_feat(DELAY_ZERO) && se->vlag > 0) - se->vlag = 0; - return NULL; } return se; @@ -6906,7 +6902,7 @@ requeue_delayed_entity(struct sched_entity *se) struct cfs_rq *cfs_rq = cfs_rq_of(se); /* - * se->sched_delayed should imply both: se->on_rq == 1. + * se->sched_delayed should imply: se->on_rq == 1. * Because a delayed entity is one that is still on * the runqueue competing until elegibility. */ @@ -6927,8 +6923,8 @@ requeue_delayed_entity(struct sched_entity *se) } } - se->sched_delayed = 0; update_load_avg(cfs_rq, se, 0); + se->sched_delayed = 0; } /*