Message-ID: <428B536E.6030700@freenet.de>
Date: Wed, 18 May 2005 16:38:38 +0200
From: Carsten Otte <cotte@freenet.de>
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To: Christoph Hellwig <hch@infradead.org>
CC: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
       schwidefsky@de.ibm.com, akpm@osdl.org
Subject: Re: [RFC/PATCH 4/5] loop: execute in place (V2)
References: <1116422644.2202.1.camel@cotte.boeblingen.de.ibm.com> <1116424432.2202.19.camel@cotte.boeblingen.de.ibm.com> <20050518142849.GC23162@infradead.org>
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Christoph Hellwig wrote:

>On Wed, May 18, 2005 at 03:53:52PM +0200, Carsten Otte wrote:
>  
>
>>[RFC/PATCH 4/5] loop: execute in place (V2)
>>
>>    
>>
>
>This should be ifdef'ed to avoid bloat for non-XIP builds.  Or just be dropped
>completely.  How much difference does it make over read/write and where does
>loop performance matter?
>  
>
I don't think loop on xip is performance critical. For page cache lookup
I see a performance difference of factor 2 on our platform because we
have decent memory bandwidth and lock contention slows things down
with many CPUs. Given that even without this patch we don't do page
cache lookups, I don't think there's much difference. Initially this patch
was written for the old loop driver that won't work without this patch...
Guess that dropping it is a good idea.

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