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Date: Wed, 26 Apr 2006 20:49:45 +0200
From: Jens Axboe <axboe@suse.de>
To: Andrew Morton <akpm@osdl.org>
Cc: Christoph Lameter <clameter@sgi.com>, linux-kernel@vger.kernel.org,
       npiggin@suse.de, linux-mm@kvack.org
Subject: Re: Lockless page cache test results
Message-ID: <20060426184945.GL5002@suse.de>
References: <20060426135310.GB5083@suse.de> <20060426095511.0cc7a3f9.akpm@osdl.org> <20060426174235.GC5002@suse.de> <20060426111054.2b4f1736.akpm@osdl.org> <Pine.LNX.4.64.0604261130450.19587@schroedinger.engr.sgi.com> <20060426114737.239806a2.akpm@osdl.org>
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On Wed, Apr 26 2006, Andrew Morton wrote:
> Christoph Lameter <clameter@sgi.com> wrote:
> >
> > On Wed, 26 Apr 2006, Andrew Morton wrote:
> > 
> > > OK.  That doesn't sound like something which a real application is likely
> > > to do ;)
> > 
> > A real application scenario may be an application that has lots of threads 
> > that are streaming data through multiple different disk channels (that 
> > are able to transfer data simultanouesly. e.g. connected to different 
> > nodes in a NUMA system) into the same address space.
> > 
> > Something like the above is fairly typical for multimedia filters 
> > processing large amounts of data.
> 
> >From the same file?
> 
> To /dev/null?

/dev/null doesn't have much to do with it, other than the fact that it
basically stresses only the input side of things. Same file is the
interesting bit of course, as that's the the granularity of the
tree_lock.

I haven't tested much else, I'll ask the tool to bench more files :)

-- 
Jens Axboe