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From: Dietmar Eggemann <dietmar.eggemann@arm.com>
To: Yuyang Du <yuyang.du@intel.com>,
	"mingo@kernel.org" <mingo@kernel.org>,
	"peterz@infradead.org" <peterz@infradead.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Cc: "pjt@google.com" <pjt@google.com>,
	"bsegall@google.com" <bsegall@google.com>,
	Morten Rasmussen <Morten.Rasmussen@arm.com>,
	"vincent.guittot@linaro.org" <vincent.guittot@linaro.org>,
	"arjan.van.de.ven@intel.com" <arjan.van.de.ven@intel.com>,
	"len.brown@intel.com" <len.brown@intel.com>,
	"rafael.j.wysocki@intel.com" <rafael.j.wysocki@intel.com>,
	"fengguang.wu@intel.com" <fengguang.wu@intel.com>,
	"boqun.feng@gmail.com" <boqun.feng@gmail.com>,
	"srikar@linux.vnet.ibm.com" <srikar@linux.vnet.ibm.com>
Subject: Re: [PATCH v8 1/4] sched: Remove rq's runnable avg
Date: Fri, 19 Jun 2015 19:27:24 +0100	[thread overview]
Message-ID: <55845F0C.8050504@arm.com> (raw)
In-Reply-To: <1434396367-27979-2-git-send-email-yuyang.du@intel.com>

Hi Yuyang,

On 15/06/15 20:26, Yuyang Du wrote:
> The current rq->avg is not used at all since its merge into kernel,
> and the code is in the scheduler's hot path, so remove it.

are you sure that this is the case? I was always under the impression
that w/ CONFIG_FAIR_GROUP_SCHED=y rq->avg (runnable_avg_sum, avg_period)
is used to calculate contrib in __update_tg_runnable_avg() for the root
group (cfs_rq->tg->css.id = 1).

On tg's w/ cfs_rq->tg->css.id > 1, se->avg (runnable_avg_sum,
avg_period) is used instead but we simply don't have a tg related se for
the root group. IMHO, that's why we have this rq::avg.

I understand that w/ the second patch in your series you don't need
rq::avg any more.

[...]

-- Dietmar

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  reply	other threads:[~2015-06-19 18:27 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-06-15 19:26 [Resend PATCH v8 0/4] sched: Rewrite runnable load and utilization average tracking Yuyang Du
2015-06-15 19:26 ` [PATCH v8 1/4] sched: Remove rq's runnable avg Yuyang Du
2015-06-19 18:27   ` Dietmar Eggemann [this message]
2015-06-21 22:26     ` Yuyang Du
2015-06-22 18:18       ` Dietmar Eggemann
2015-06-15 19:26 ` [PATCH v8 2/4] sched: Rewrite runnable load and utilization average tracking Yuyang Du
2015-06-19  6:00   ` Boqun Feng
2015-06-18 23:05     ` Yuyang Du
2015-06-19  7:57       ` Boqun Feng
2015-06-19  3:11         ` Yuyang Du
2015-06-19 12:22           ` Boqun Feng
2015-06-21 22:43             ` Yuyang Du
2015-06-15 19:26 ` [PATCH v8 3/4] sched: Init cfs_rq's sched_entity load average Yuyang Du
2015-06-15 19:26 ` [PATCH v8 4/4] sched: Remove task and group entity load when they are dead Yuyang Du
     [not found] ` <20150617030650.GB5695@fixme-laptop.cn.ibm.com>
2015-06-17  5:15   ` [Resend PATCH v8 0/4] sched: Rewrite runnable load and utilization average tracking Boqun Feng
2015-06-17  3:11     ` Yuyang Du
2015-06-17 13:06       ` Boqun Feng
2015-06-17 19:04         ` Yuyang Du
2015-06-18  6:31       ` Wanpeng Li
2015-06-17 22:46         ` Yuyang Du
2015-06-18 11:48           ` Wanpeng Li
2015-06-18 18:25             ` Yuyang Du
2015-06-19  3:33               ` Wanpeng Li

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