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Date: Wed, 13 Apr 2011 12:11:30 +0900
From: Tejun Heo <tj@kernel.org>
To: Shaohua Li <shaohua.li@intel.com>
Cc: lkml <linux-kernel@vger.kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        "cl@linux.com" <cl@linux.com>
Subject: Re: [PATCH 4/4]percpu_counter: use atomic64 for counter
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 <20110412191534.GE16342@mtj.dyndns.org>
 <1302657428.3981.149.camel@sli10-conroe>
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Hello,

On Wed, Apr 13, 2011 at 09:17:08AM +0800, Shaohua Li wrote:
> yes, we do have something this matters. the vm_committed_as
> percpu_counter could heavily contend the lock. please see
> http://marc.info/?l=linux-kernel&m=130144786026044&w=2
> We should fix vm_committed_as, but the atomic method also gives me very
> good output. When I do mmap/munmap test in a 24 CPU system, the atomic
> method gives me 50x faster.

That's good to hear.  Care to provide the performance info in the
commit message too?

Thanks.

-- 
tejun
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