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From: "Chris Friesen" <cfriesen@nortel.com>
To: vatsa@linux.vnet.ibm.com
Cc: linux-kernel@vger.kernel.org, mingo@elte.hu,
	a.p.zijlstra@chello.nl, pj@sgi.com,
	Balbir Singh <balbir@in.ibm.com>,
	aneesh.kumar@linux.vnet.ibm.com, dhaval@linux.vnet.ibm.com
Subject: Re: fair group scheduler not so fair?
Date: Tue, 27 May 2008 12:13:46 -0600	[thread overview]
Message-ID: <483C4F5A.2010104@nortel.com> (raw)
In-Reply-To: <20080527171528.GD30285@linux.vnet.ibm.com>

Srivatsa Vaddagiri wrote:

> But first, note that Groups "a" and "b" share bandwidth with all tasks
> in /dev/cgroup/tasks.

Ah, good point.  I've switched over to your group setup for testing.

> The following experimental patch (on top of 2.6.26-rc3 +
> http://programming.kicks-ass.net/kernel-patches/sched-smp-group-fixes/) seems 
> to fix the problem.

> Can you check if this makes a difference for you as well?

Initially it looked promising.  I put pid 2498 in group A, and pids 2499 
and 2500 in group B.  2498 got basically a full cpu, and the other two 
got 50% each.

However, I then moved pid 2499 from group B to group A, and the system 
got stuck in the following behaviour:

2498 cfriesen  20   0  3800  392  336 R 99.7  0.0   3:00.22 cat
2500 cfriesen  20   0  3800  392  336 R 66.7  0.0   1:39.10 cat
2499 cfriesen  20   0  3800  392  336 R 33.0  0.0   1:24.31 cat

I reproduced this a number of times.

Chris

  reply	other threads:[~2008-05-27 18:14 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-05-21 23:59 fair group scheduler not so fair? Chris Friesen
2008-05-22  6:56 ` Peter Zijlstra
2008-05-22 20:02   ` Chris Friesen
2008-05-22 20:07     ` Peter Zijlstra
2008-05-22 20:18       ` Li, Tong N
2008-05-22 21:13         ` Peter Zijlstra
2008-05-23  0:17           ` Chris Friesen
2008-05-23  7:44             ` Srivatsa Vaddagiri
2008-05-23  9:42         ` Srivatsa Vaddagiri
2008-05-23  9:39           ` Peter Zijlstra
2008-05-23 10:19             ` Srivatsa Vaddagiri
2008-05-23 10:16               ` Peter Zijlstra
2008-05-27 17:15 ` Srivatsa Vaddagiri
2008-05-27 18:13   ` Chris Friesen [this message]
2008-05-28 16:33     ` Srivatsa Vaddagiri
2008-05-28 18:35       ` Chris Friesen
2008-05-28 18:47         ` Dhaval Giani
2008-05-29  2:50         ` Srivatsa Vaddagiri
2008-05-29 16:46         ` Srivatsa Vaddagiri
2008-05-29 16:47           ` Srivatsa Vaddagiri
2008-05-29 21:30           ` Chris Friesen
2008-05-30  6:43             ` Dhaval Giani
2008-05-30 10:21               ` Srivatsa Vaddagiri
2008-05-30 11:36             ` Srivatsa Vaddagiri
2008-06-02 20:03               ` Chris Friesen
2008-05-27 17:28 ` Srivatsa Vaddagiri

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