From: Trond Myklebust <trond.myklebust@fys.uio.no>
Subject: Re: Poor NFS performance, kernel 2.6.6.
Date: Fri, 28 May 2004 15:19:28 -0400
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To: Harald Hannelius <harald+nfs@arcada.fi>
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P=E5 fr , 28/05/2004 klokka 14:03, skreiv Harald Hannelius:

> I guess (as a total don't-know) that nfsd reads and writes files in a
> different way than local processes do. I read somewhere something about
> read-ahead but that was in 2.6.0-pre-something..

Hmm... The current readahead code does a load of crap in order to
determine whether or not the user is doing linear or random I/O. It may
be that the nfsd server with all its multi-threading and out-of-sequence
I/O is triggering the random I/O readahead code (which of course aims to
limit readahead).

Cheers
  Trond


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