[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <55898E28.7040706@arm.com>
Date: Tue, 23 Jun 2015 17:49:44 +0100
From: Dietmar Eggemann <dietmar.eggemann@....com>
To: Yuyang Du <yuyang.du@...el.com>,
"mingo@...nel.org" <mingo@...nel.org>,
"peterz@...radead.org" <peterz@...radead.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC: "pjt@...gle.com" <pjt@...gle.com>,
"bsegall@...gle.com" <bsegall@...gle.com>,
Morten Rasmussen <Morten.Rasmussen@....com>,
"vincent.guittot@...aro.org" <vincent.guittot@...aro.org>,
"len.brown@...el.com" <len.brown@...el.com>,
"rafael.j.wysocki@...el.com" <rafael.j.wysocki@...el.com>,
"fengguang.wu@...el.com" <fengguang.wu@...el.com>,
"boqun.feng@...il.com" <boqun.feng@...il.com>,
"srikar@...ux.vnet.ibm.com" <srikar@...ux.vnet.ibm.com>
Subject: Re: [PATCH v9 1/4] sched: Remove rq's runnable avg
On 23/06/15 01:08, Yuyang Du wrote:
> The per-rq runnable averages (rq->avg) was introduced by Ben with this commit:
>
> commit 18bf2805d9b30cb823d4919b42cd230f59c7ce1f
> Author: Ben Segall <bsegall@...gle.com>
> Date: Thu Oct 4 12:51:20 2012 +0200
>
> sched: Maintain per-rq runnable averages
>
> Since runqueues do not have a corresponding sched_entity we instead embed a
> sched_avg structure directly.
>
> Signed-off-by: Ben Segall <bsegall@...gle.com>
> Reviewed-by: Paul Turner <pjt@...gle.com>
> Signed-off-by: Peter Zijlstra <a.p.zijlstra@...llo.nl>
> Link: http://lkml.kernel.org/r/20120823141506.442637130@google.com
> Signed-off-by: Ingo Molnar <mingo@...nel.org>
>
> With CONFIG_FAIR_GROUP_SCHED=y, the rq->avg (runnable_avg_sum, avg_period) is
> used to calc the contrib in __update_tg_runnable_avg() for the root group.
>
> But the root group's load data is never consumed since its merge into kernel
> in 2012. The basic reason is we have just one root group, and it is
> meaningless to give it weight. As the extra code is in the scheduler's
> hot path, so it is better to remove it.
>
> Signed-off-by: Yuyang Du <yuyang.du@...el.com>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@....com>
Tested-by: Dietmar Eggemann <dietmar.eggemann@....com>
There is an additional clean-up possible since idle_[enter|exit]_fair()
are empty now.
[...]
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists