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From: Peter Williams <peterw@aurema.com>
To: MAEDA Naoaki <maeda.naoaki@jp.fujitsu.com>
Cc: Kirill Korotaev <dev@openvz.org>, Srivatsa <vatsa@in.ibm.com>,
	CKRM <ckrm-tech@lists.sourceforge.net>,
	Balbir Singh <bsingharora@gmail.com>,
	Mike Galbraith <efault@gmx.de>,
	Peter Williams <pwil3058@bigpond.net.au>,
	Con Kolivas <kernel@kolivas.org>,
	Linux Kernel <linux-kernel@vger.kernel.org>,
	Sam Vilain <sam@vilain.net>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	Kingsley Cheung <kingsley@aurema.com>,
	Rene Herman <rene.herman@keyaccess.nl>,
	Ingo Molnar <mingo@elte.hu>
Subject: Re: [ckrm-tech] [RFC 0/4] sched: Add CPU rate caps (improved)
Date: Fri, 09 Jun 2006 16:05:08 +1000	[thread overview]
Message-ID: <44890F94.3050209@aurema.com> (raw)
In-Reply-To: <44890C0A.1000005@jp.fujitsu.com>

MAEDA Naoaki wrote:
> Peter Williams wrote:
>> I've done some informal testing with smaller values of CAP_STATS_OFFSET 
>> and there is only a minor improvement.
>>
>> However, something that does improve behaviour for short lived tasks is 
>> to increase the value of HZ.  This is because the basic unit of CPU
>> allocation by the scheduler is 1/HZ and this is also the minimum time 
>> (and granularity) with which sinbinning and other capping measures can 
>> be implemented.  This is the fundamental limiting factor for the 
>> accuracy of capping i.e. if everything worked perfectly the best 
>> granularity that can be expected from capping of short lived tasks is 
>> 1000 / (HZ * duration) where duration is in seconds.
> 
> I already defines CONFIG_HZ=1000. Do you suggest increasing more?

No.

Peter
-- 
Dr Peter Williams, Chief Scientist         <peterw@aurema.com>
Aurema Pty Limited
Level 2, 130 Elizabeth St, Sydney, NSW 2000, Australia
Tel:+61 2 9698 2322  Fax:+61 2 9699 9174 http://www.aurema.com

  reply	other threads:[~2006-06-09  6:06 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20060606023708.2801.24804.sendpatchset@heathwren.pw.nest>
2006-06-07  8:05 ` [ckrm-tech] [RFC 0/4] sched: Add CPU rate caps (improved) MAEDA Naoaki
2006-06-07 12:44   ` Peter Williams
2006-06-08  7:50   ` Peter Williams
2006-06-09  0:57     ` Peter Williams
2006-06-09  5:50       ` MAEDA Naoaki
2006-06-09  6:05         ` Peter Williams [this message]
2006-06-09  5:41     ` MAEDA Naoaki
2006-06-09  6:38       ` Peter Williams

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