From mboxrd@z Thu Jan  1 00:00:00 1970
From: Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH RFC] mm: Implement balance_dirty_pages() through
 waiting for flusher thread
Date: Tue, 22 Jun 2010 15:59:04 +0200
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Cc: Jan Kara <jack@suse.cz>, Dave Chinner <david@fromorbit.com>,
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To: Wu Fengguang <fengguang.wu@intel.com>
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On Tue, 2010-06-22 at 21:52 +0800, Wu Fengguang wrote:
> 
> This test shows that atomic_dec_and_test() is about 4.5 times slower
> than plain i-- in a 4-core CPU. Not bad. 

It gets worse - much worse - on larger machines.