From: Peter Zijlstra <peterz@infradead.org>
To: Abel Wu <wuyun.abel@bytedance.com>
Cc: Ingo Molnar <mingo@kernel.org>,
Vincent Guittot <vincent.guittot@linaro.org>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Valentin Schneider <valentin.schneider@arm.com>,
Barry Song <21cnbao@gmail.com>,
Benjamin Segall <bsegall@google.com>,
Chen Yu <yu.c.chen@intel.com>,
Daniel Jordan <daniel.m.jordan@oracle.com>,
"Gautham R . Shenoy" <gautham.shenoy@amd.com>,
Joel Fernandes <joel@joelfernandes.org>,
K Prateek Nayak <kprateek.nayak@amd.com>,
Mike Galbraith <efault@gmx.de>, Qais Yousef <qyousef@layalina.io>,
Tim Chen <tim.c.chen@linux.intel.com>,
Yicong Yang <yangyicong@huawei.com>,
Youssef Esmat <youssefesmat@chromium.org>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/4] sched/eevdf: O(1) fastpath for task selection
Date: Tue, 7 Nov 2023 11:42:07 +0100 [thread overview]
Message-ID: <20231107104207.GT8262@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <b2b70241-04fe-4064-ba72-c5ed03a4d4fd@bytedance.com>
On Tue, Nov 07, 2023 at 06:12:49PM +0800, Abel Wu wrote:
> > @@ -904,7 +905,7 @@ static struct sched_entity *pick_eevdf(struct cfs_rq *cfs_rq)
> > * in this cfs_rq, saving some cycles.
> > */
> > if (cfs_rq->nr_running == 1)
> > - return curr && curr->on_rq ? curr : __node_2_se(node);
> > + return curr && curr->on_rq ? curr : se;
>
> Maybe we can reduce memory footprint on curr by:
>
> return se ? se : curr;
Irrespective, I think that logic makes more sense. If we know we have
but one task and the tree has a task, it must be that task, otherwise,
current must be it.
Anyway, I was still staring at the previous patch, flipping the tree
around like that is clever. Yes I suppose that ought to work just fine.
next prev parent reply other threads:[~2023-11-07 10:42 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-07 9:05 [PATCH 0/4] sched/eevdf: Optimize reweight and pick Abel Wu
2023-11-07 9:05 ` [PATCH 1/4] sched/eevdf: Fix vruntime adjustment on reweight Abel Wu
2023-11-07 9:52 ` Peter Zijlstra
2023-11-14 21:57 ` [tip: sched/urgent] " tip-bot2 for Abel Wu
2023-11-15 15:36 ` [PATCH 1/4] " Yiwei Lin
2023-11-16 4:48 ` Abel Wu
2023-11-16 4:59 ` Yiwei Lin
2023-11-16 9:01 ` Abel Wu
2023-11-16 5:07 ` Abel Wu
2023-11-16 6:51 ` Yiwei Lin
2023-11-16 7:11 ` Abel Wu
2024-02-29 9:24 ` Tianchen Ding
2024-02-29 14:25 ` Abel Wu
2024-03-01 6:41 ` Tianchen Ding
2024-03-01 8:30 ` Abel Wu
2024-03-01 10:04 ` Tianchen Ding
2023-11-07 9:05 ` [PATCH 2/4] sched/eevdf: Sort the rbtree by virtual deadline Abel Wu
2023-11-07 11:03 ` Peter Zijlstra
2023-11-07 11:06 ` Abel Wu
2023-11-07 23:26 ` Benjamin Segall
2023-11-08 8:51 ` Abel Wu
2023-11-07 9:05 ` [PATCH 3/4] sched/eevdf: O(1) fastpath for task selection Abel Wu
2023-11-07 10:12 ` Abel Wu
2023-11-07 10:42 ` Peter Zijlstra [this message]
2023-11-07 9:05 ` [PATCH 4/4] sched/stats: branch statistics for pick_eevdf Abel Wu
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