Date: Wed, 26 Mar 2008 10:56:17 -0700 (PDT)
From: Christoph Lameter <clameter@sgi.com>
To: Paul Mackerras <paulus@samba.org>
cc: Andi Kleen <andi@firstfloor.org>, David Miller <davem@davemloft.net>,
       linux-mm@kvack.org, linux-kernel@vger.kernel.org,
       linux-ia64@vger.kernel.org, torvalds@linux-foundation.org
Subject: Re: larger default page sizes...
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On Wed, 26 Mar 2008, Paul Mackerras wrote:

> So the improvement in the user time is almost all due to the reduced
> TLB misses (as one would expect).  For the system time, using 64k
> pages in the VM reduces it by about 21%, and using 64k hardware pages
> reduces it by another 30%.  So the reduction in kernel overhead is
> significant but not as large as the impact of reducing TLB misses.

One should emphasize that this test was a kernel compile which is not 
a load that gains much from larger pages. 4k pages are mostly okay for 
loads that use large amounts of small files.


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