From: Mike Galbraith <efault@gmx.de>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Ingo Molnar <mingo@elte.hu>,
Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>,
dhaval@linux.vnet.ibm.com, tong.n.li@intel.com,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/7] Single RQ group scheduling
Date: Tue, 19 Feb 2008 07:10:21 +0100 [thread overview]
Message-ID: <1203401421.4252.13.camel@homer.simson.net> (raw)
In-Reply-To: <20080218095535.629736000@chello.nl>
On Mon, 2008-02-18 at 10:55 +0100, Peter Zijlstra wrote:
> This is my current queue for single RQ group scheduling.
I took these out for a brief maxcpus=1 spin yesterday, and noticed
something. Running 4 copies of chew-max, one as a user, the context
switch rate was high (~1800/s). I increased sched_min_granularity_ns to
see if that would lower it, and it did, but it also upset fairness.
With sched_min_granularity_ns bumped to half of sched_latency_ns (40ms
default) it was a largish skew.
top - 06:58:46 up 3 min, 15 users, load average: 4.71, 2.53, 1.04
Tasks: 214 total, 9 running, 204 sleeping, 0 stopped, 1 zombie
Cpu(s): 39.0%us, 61.0%sy, 0.0%ni, 0.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ P COMMAND
5389 mikeg 20 0 1464 364 304 R 40.1 0.0 0:29.71 0 chew-max
5373 root 20 0 1464 364 304 R 19.0 0.0 0:16.30 0 chew-max
5388 root 20 0 1464 364 304 R 19.0 0.0 0:15.79 0 chew-max
5374 root 20 0 1464 364 304 R 18.6 0.0 0:15.90 0 chew-max
-Mike
prev parent reply other threads:[~2008-02-19 6:10 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-02-18 9:55 [PATCH 0/7] Single RQ group scheduling Peter Zijlstra
2008-02-18 9:55 ` [PATCH 1/7] sched: cleanup old and rarely used debug features Peter Zijlstra
2008-02-18 9:55 ` [PATCH 2/7] sched: fair-group scheduling vs latency Peter Zijlstra
2008-02-18 9:55 ` [PATCH 3/7] sched: fair-group: de-couple load-balancing from the rb-trees Peter Zijlstra
2008-02-18 9:55 ` [PATCH 4/7] sched: fair-group: single RQ approach Peter Zijlstra
2008-02-18 9:55 ` [PATCH 5/7] sched: remove sysctl_sched_batch_wakeup_granularity Peter Zijlstra
2008-02-18 9:55 ` [PATCH 6/7] sched: fair: optimize sched_slice() Peter Zijlstra
2008-02-18 9:55 ` [PATCH 7/7] sched: fair: vruntime spread Peter Zijlstra
2008-02-19 6:10 ` Mike Galbraith [this message]
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