linux-kernel - Re: [PATCH 2/2] sched: update runqueue clock before migrations away

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <52B1753A.7060501@arm.com>
Date:	Wed, 18 Dec 2013 10:13:14 +0000
From:	Chris Redpath <chris.redpath@....com>
To:	"bsegall@...gle.com" <bsegall@...gle.com>
CC:	Peter Zijlstra <peterz@...radead.org>,
	"pjt@...gle.com" <pjt@...gle.com>,
	"mingo@...hat.com" <mingo@...hat.com>,
	"alex.shi@...aro.org" <alex.shi@...aro.org>,
	Morten Rasmussen <Morten.Rasmussen@....com>,
	Dietmar Eggemann <Dietmar.Eggemann@....com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Vincent Guittot <vincent.guittot@...aro.org>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Chris Redpath <Chris.Redpath@....com>
Subject: Re: [PATCH 2/2] sched: update runqueue clock before migrations away

On 17/12/13 18:03, bsegall@...gle.com wrote:
> __synchronize_entity_decay will decay load_avg_contrib in order to
> figure out how much to remove from old_cfs_rq->blocked_load.
> update_entity_load_avg will update the underlying runnable_avg_sum/period that
> is used to update load_avg_contrib.
>
> (Normally we update runnable_avg_sum, which updates load_avg_contrib via
> __update_entity_load_avg_contrib. Here we go in the reverse direction
> because we don't hold the right rq locks at the right times.)
>

Thanks Ben, got it now. The only question remaining for me to figure out 
is if I need to include the missed tick time in the contrib decay or not 
- I definitely need to include it in the negative decay count we send 
through a migration. I'll go and check the places we use the removed 
load and update blocked load again.

--
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/