From: Peter Zijlstra <peterz@infradead.org>
To: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: mingo@redhat.com, vincent.guittot@linaro.org,
dietmar.eggemann@arm.com, bsegall@google.com,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] sched/fair: optimize entity_tick()
Date: Mon, 18 Jul 2022 12:10:29 +0200 [thread overview]
Message-ID: <YtUxlVPGftwLWQNV@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <20220718094937.37360-1-zhangpeng.00@bytedance.com>
On Mon, Jul 18, 2022 at 05:49:37PM +0800, Peng Zhang wrote:
> From: "zhangpeng.00" <zhangpeng.00@bytedance.com>
>
> entity_tick() will be called to check preemption by calculating each
> sched_entity's time_slice in a task group tree from bottom to top.
>
> If a need_resched_flag is set by a checking of a sched_entity,
> there is no necessary to check preemption of the sched_entity's
> parent and ancestor entity.
>
> So we can test if the need_resched_flag has been set before calling
> check_preempt_tick() to avoid unnecessary calculations.
>
> Signed-off-by: zhangpeng.00 <zhangpeng.00@bytedance.com>
Optimization patches should come with numbers showing they're worth it.
Also; did you consider side-effects from check_preempt_tick(), like
clearing buddy state etc.. ?
next prev parent reply other threads:[~2022-07-18 10:10 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-18 9:49 Peng Zhang
2022-07-18 10:10 ` Peter Zijlstra [this message]
2022-07-18 18:53 ` kernel test robot
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