From: Bharata B Rao <bharata@linux.vnet.ibm.com>
To: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
Balaji Rao <balajirrao@gmail.com>,
Dhaval Giani <dhaval@linux.vnet.ibm.com>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Balbir Singh <balbir@linux.vnet.ibm.com>,
Ingo Molnar <mingo@elte.hu>,
Martin Schwidefsky <schwidefsky@de.ibm.com>,
seto.hidetoshi@jp.fujitsu.com
Subject: Re: [PATCH] cpuacct: VIRT_CPU_ACCOUNTING don't prevent percpu cputime count
Date: Tue, 28 Apr 2009 13:20:55 +0530 [thread overview]
Message-ID: <20090428075055.GD3825@in.ibm.com> (raw)
In-Reply-To: <20090428163509.EBCF.A69D9226@jp.fujitsu.com>
On Tue, Apr 28, 2009 at 04:38:51PM +0900, KOSAKI Motohiro wrote:
> > On Tue, Apr 28, 2009 at 03:53:32PM +0900, KOSAKI Motohiro wrote:
>
> > BTW, did you observe any real problem with the percpu counter spinlock ?
>
> No.
> I review percpu_counter() caller recently and it seems stragen usage.
>
I should have phrased the question better ...
So have you found any performance degradation with any benchmarks/workloads
on archs which define VIRT_CPU_ACCOUNTING due to percpu_counter spinlock
being taken on every tick ? If the answer is no, don't you think we could
wait before making the kind of change you are proposing ?
Regards,
Bharata.
next prev parent reply other threads:[~2009-04-28 7:51 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-28 6:53 [PATCH] cpuacct: VIRT_CPU_ACCOUNTING don't prevent percpu cputime count KOSAKI Motohiro
2009-04-28 7:31 ` Bharata B Rao
2009-04-28 7:38 ` KOSAKI Motohiro
2009-04-28 7:50 ` Bharata B Rao [this message]
2009-04-28 8:10 ` KOSAKI Motohiro
2009-04-28 10:37 ` Bharata B Rao
2009-04-29 2:31 ` KOSAKI Motohiro
2009-04-29 3:30 ` Bharata B Rao
2009-04-28 22:08 ` Balbir Singh
2009-04-29 2:26 ` KOSAKI Motohiro
2009-04-29 5:44 ` Balbir Singh
2009-04-29 6:08 ` KOSAKI Motohiro
2009-04-29 3:21 ` Bharata B Rao
2009-04-29 6:04 ` Balbir Singh
2009-04-29 6:09 ` Bharata B Rao
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