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Date: Tue, 13 Sep 2011 10:33:06 +0530
From: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Turner <pjt@google.com>,
        Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>,
        Vladimir Davydov <vdavydov@parallels.com>,
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        Bharata B Rao <bharata@linux.vnet.ibm.com>,
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        Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>,
        Ingo Molnar <mingo@elte.hu>, Pavel Emelianov <xemul@parallels.com>
Subject: Re: CFS Bandwidth Control - Test results of cgroups tasks pinned vs
 unpinnede
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* Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> [2011-09-13 09:45:45]:

> * Peter Zijlstra <a.p.zijlstra@chello.nl> [2011-09-12 14:35:43]:
> 
> > Of course it does.. and I bet you can improve that slightly if you
> > manage to fix some of the numerical nightmares that live in the cgroup
> > load-balancer (Paul, care to share your WIP?)
> 
> Booting with "nohz=off" also helps significantly.
> 
> With nohz=on, average idle time (over 1 min) is 10.3%
> With nohz=off, average idle time (over 1 min) is 3.9%

Tuning min_interval and max_interval of various sched_domains to 1 [a]
and also setting sched_cfs_bandwidth_slice_us to 500 does cut down idle
time further to 2.7% ..

This is perhaps not optimal (as it may lead to more lock contentions), but 
something to note for those who care for both capping and utilization in
equal measure!

- vatsa