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Date: Sun, 27 Aug 2006 15:14:50 -0700 (PDT)
From: Christoph Lameter <clameter@sgi.com>
To: Andi Kleen <ak@suse.de>
cc: Dong Feng <middle.fengdong@gmail.com>, Paul Mackerras <paulus@samba.org>,
       linux-kernel@vger.kernel.org
Subject: Re: Why Semaphore Hardware-Dependent?
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On Sun, 27 Aug 2006, Andi Kleen wrote:

> x86-64 always uses the spinlocked version (vs i386 using the atomic one)
> and I haven't heard of anybody complaining.

Ia64 has special counters for rwsemaphores. I'd like to see if there is 
any performance loss. mmap_sem is a rwsemaphore. This is performance 
critical.