Date: Mon, 18 Jan 2010 19:21:51 +1100
From: Anton Blanchard <anton@samba.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Bharata B Rao <bharata@linux.vnet.ibm.com>,
       KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
       Ingo Molnar <mingo@elte.hu>, Balbir Singh <balbir@linux.vnet.ibm.com>,
       mingo@redhat.com, hpa@zytor.com, linux-kernel@vger.kernel.org,
       schwidefsky@de.ibm.com, balajirrao@gmail.com, dhaval@linux.vnet.ibm.com,
       tglx@linutronix.de, kamezawa.hiroyu@jp.fujitsu.com,
       akpm@linux-foundation.org, Tony Luck <tony.luck@intel.com>,
       Fenghua Yu <fenghua.yu@intel.com>,
       Heiko Carstens <heiko.carstens@de.ibm.com>, linux390@de.ibm.com
Subject: Re: [PATCH] sched: cpuacct: Use bigger percpu counter batch values
 for stats counters
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Hi Peter,

> Seems like a good idea, but isn't that batch number rather static? If
> so, computing it in some init path would save that multiply on the
> actual accounting path.

It is mostly static, but percpu_counter_batch does change with hotplug
operations. Adding a hotplug notifier felt like a lot of work but I was
worried we have issues if we didn't scale with hotplug add operations.

Anton
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