From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Paul Turner <pjt@google.com>
Cc: linux-kernel@vger.kernel.org, Venki Pallipadi <venki@google.com>,
Srivatsa Vaddagiri <vatsa@in.ibm.com>,
Vincent Guittot <vincent.guittot@linaro.org>,
Nikunj A Dadhania <nikunj@linux.vnet.ibm.com>,
Mike Galbraith <efault@gmx.de>,
Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>,
Ben Segall <bsegall@google.com>, Ingo Molnar <mingo@elte.hu>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Morten Rasmussen <Morten.Rasmussen@arm.com>,
Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Subject: Re: [PATCH 09/16] sched: normalize tg load contributions against runnable time
Date: Fri, 06 Jul 2012 14:23:59 +0200 [thread overview]
Message-ID: <1341577439.7709.49.camel@twins> (raw)
In-Reply-To: <20120628022414.30496.11931.stgit@kitami.mtv.corp.google.com>
On Wed, 2012-06-27 at 19:24 -0700, Paul Turner wrote:
> + contrib = div_u64(sa->runnable_avg_sum << 12,
> + sa->runnable_avg_period + 1);
> +
> + /*
> + * Unlike a task-entity, a group entity may be using >=1 cpu globally.
> + * However, in the case that it's using <1 cpu we need to form a
> + * correction term so that we contribute the same load as a task of
> + * equal weight. (Global runnable time is taken as a fraction over
> + * 2^12.)
> + */
> + runnable_avg = atomic_read(&tg->runnable_avg);
> + if (runnable_avg < (1<<12)) {
> + se->avg.load_avg_contrib *= runnable_avg;
> + se->avg.load_avg_contrib /= (1<<12);
> + }
Did we really have to open-code a 4096 fixed point here? Couldn't we
re-use some of the existing _SCALE things.. if not why 12?
next prev parent reply other threads:[~2012-07-06 12:24 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-06-28 2:24 [PATCH 00/16] Series short description Paul Turner
2012-06-28 2:24 ` [PATCH 09/16] sched: normalize tg load contributions against runnable time Paul Turner
2012-06-29 7:26 ` Namhyung Kim
2012-07-04 19:48 ` Peter Zijlstra
2012-07-06 11:52 ` Peter Zijlstra
2012-07-12 1:08 ` Andre Noll
2012-07-12 0:02 ` Paul Turner
2012-07-06 12:23 ` Peter Zijlstra [this message]
2012-06-28 2:24 ` [PATCH 06/16] sched: account for blocked load waking back up Paul Turner
2012-06-28 2:24 ` [PATCH 02/16] sched: maintain per-rq runnable averages Paul Turner
2012-06-28 2:24 ` [PATCH 01/16] sched: track the runnable average on a per-task entitiy basis Paul Turner
2012-06-28 6:06 ` Namhyung Kim
2012-07-12 0:14 ` Paul Turner
2012-07-04 15:32 ` Peter Zijlstra
2012-07-12 0:12 ` Paul Turner
2012-06-28 2:24 ` [PATCH 04/16] sched: maintain the load contribution of blocked entities Paul Turner
2012-06-29 1:27 ` Namhyung Kim
2012-06-28 2:24 ` [PATCH 07/16] sched: aggregate total task_group load Paul Turner
2012-06-28 2:24 ` [PATCH 05/16] sched: add an rq migration call-back to sched_class Paul Turner
2012-06-29 1:32 ` Namhyung Kim
2012-06-28 2:24 ` [PATCH 08/16] sched: compute load contribution by a group entity Paul Turner
2012-06-28 2:24 ` [PATCH 03/16] sched: aggregate load contributed by task entities on parenting cfs_rq Paul Turner
2012-06-28 6:33 ` Namhyung Kim
2012-07-04 15:28 ` Peter Zijlstra
2012-07-06 14:53 ` Peter Zijlstra
2012-07-09 9:15 ` Ingo Molnar
2012-06-28 2:24 ` [PATCH 11/16] sched: replace update_shares weight distribution with per-entity computation Paul Turner
2012-06-28 2:24 ` [PATCH 16/16] sched: introduce temporary FAIR_GROUP_SCHED dependency for load-tracking Paul Turner
2012-06-28 2:24 ` [PATCH 12/16] sched: refactor update_shares_cpu() -> update_blocked_avgs() Paul Turner
2012-06-29 7:28 ` Namhyung Kim
2012-07-12 0:03 ` Paul Turner
2012-07-05 11:58 ` Peter Zijlstra
2012-07-12 0:11 ` Paul Turner
2012-07-12 14:40 ` Peter Zijlstra
2012-06-28 2:24 ` [PATCH 15/16] sched: implement usage tracking Paul Turner
2012-06-28 2:24 ` [PATCH 13/16] sched: update_cfs_shares at period edge Paul Turner
2012-06-28 2:24 ` [PATCH 10/16] sched: maintain runnable averages across throttled periods Paul Turner
2012-06-28 2:24 ` [PATCH 14/16] sched: make __update_entity_runnable_avg() fast Paul Turner
2012-07-04 15:41 ` Peter Zijlstra
2012-07-04 17:20 ` Peter Zijlstra
2012-07-09 20:18 ` Benjamin Segall
2012-07-10 10:51 ` Peter Zijlstra
2012-07-12 0:15 ` Paul Turner
2012-07-12 14:30 ` Peter Zijlstra
2012-07-04 16:51 ` Peter Zijlstra
2012-08-23 14:14 [patch 00/16] sched: per-entity load-tracking pjt
2012-08-23 14:14 ` [patch 09/16] sched: normalize tg load contributions against runnable time pjt
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