linux-kernel - Re: [PATCH v3] sched/cpufreq: optimize cpufreq update kicker to avoid update multiple times

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Message-ID: <20160425143133.GK3430@twins.programming.kicks-ass.net>
Date:	Mon, 25 Apr 2016 16:31:33 +0200
From:	Peter Zijlstra <peterz@...radead.org>
To:	"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>
Cc:	Wanpeng Li <kernellwp@...il.com>, Ingo Molnar <mingo@...hat.com>,
	linux-kernel@...r.kernel.org, Wanpeng Li <wanpeng.li@...mail.com>,
	Linux PM <linux-pm@...r.kernel.org>
Subject: Re: [PATCH v3] sched/cpufreq: optimize cpufreq update kicker to
 avoid update multiple times

On Fri, Apr 22, 2016 at 02:04:56PM +0200, Rafael J. Wysocki wrote:
> [Added linux-pm to the CC - can you please do so for PM-related patches in
> the future?]
> 
> On 4/22/2016 11:07 AM, Wanpeng Li wrote:
> >From: Wanpeng Li <wanpeng.li@...mail.com>
> >
> >Sometimes delta_exec is 0 due to update_curr() is called multiple times,
> >this is captured by:
> >
> >	u64 delta_exec = rq_clock_task(rq) - curr->se.exec_start;
> >
> >This patch optimizes the cpufreq update kicker by bailing out when nothing
> >changed, it will benefit the upcoming schedutil, since otherwise it will
> >(over)react to the special util/max combination.
> >
> >Signed-off-by: Wanpeng Li <wanpeng.li@...mail.com>
> 
> The changelog looks better now, thanks!
> 
> Peter, do I think correctly that you're going to take care of this one?  Or
> do you want me to take it?

YEah, looks fine. I'll take it.

Thanks!