From: Ken Chen <kenchen@google.com>
To: bharata@linux.vnet.ibm.com
Cc: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@elte.hu>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Dhaval Giani <dhaval@linux.vnet.ibm.com>,
Srivatsa Vaddagiri <vatsa@in.ibm.com>,
Balbir Singh <balbir@linux.vnet.ibm.com>
Subject: Re: CFS group scheduler fairness broken starting from 2.6.29-rc1
Date: Thu, 23 Jul 2009 15:17:18 -0700 [thread overview]
Message-ID: <b040c32a0907231517l265a9528w628d48fa3625e261@mail.gmail.com> (raw)
In-Reply-To: <20090723075735.GA18878@in.ibm.com>
On Thu, Jul 23, 2009 at 12:57 AM, Bharata BRao<bharata@linux.vnet.ibm.com> wrote:> Hi,>> Group scheduler fainess is broken since 2.6.29-rc1. git bisect led me> to this commit:>> commit ec4e0e2fe018992d980910db901637c814575914> Author: Ken Chen <kenchen@google.com>> Date: Tue Nov 18 22:41:57 2008 -0800>> sched: fix inconsistency when redistribute per-cpu tg->cfs_rq shares>> Impact: make load-balancing more consistent> ....>> ======================================================================> % CPU time division b/n groups> Group 2.6.29-rc1 2.6.29-rc1 w/o the above patch> ======================================================================> a with 8 tasks 44 31> b with 5 tasks 32 34> c with 3 tasks 22 34> ======================================================================> All groups had equal shares.
What value did you use for each task_group's share? For very largevalue of tg->shares, it could be that all of the boost went to one CPUand subsequently causes load-balancer to shuffle tasks around. Do yousee any unexpected task migration?
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next prev parent reply other threads:[~2009-07-23 22:17 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-07-23 7:57 Bharata B Rao
2009-07-23 22:17 ` Ken Chen [this message]
2009-07-24 4:30 ` Bharata B Rao
2009-07-27 12:09 ` Peter Zijlstra
2009-07-28 4:14 ` Bharata B Rao
2009-07-28 7:28 ` Peter Zijlstra
2009-08-02 13:12 ` [tip:sched/core] sched: Fix cgroup smp fairness tip-bot for Peter Zijlstra
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