From: Greg Banks <gnb@melbourne.sgi.com>
To: Neil Brown <neilb@cse.unsw.edu.au>
Cc: James Pearson <james-p@moving-picture.com>,
Trond Myklebust <trond.myklebust@fys.uio.no>,
nfs@lists.sourceforge.net
Subject: Re: Different NFSSVC_MAXBLKSIZE for udp and tcp clients?
Date: Thu, 27 Nov 2003 12:33:50 +1100 [thread overview]
Message-ID: <3FC5547E.7EBF817@melbourne.sgi.com> (raw)
In-Reply-To: 16325.18142.376089.406722@notabene.cse.unsw.edu.au
Neil Brown wrote:
>
> On Thursday November 27, gnb@melbourne.sgi.com wrote:
> > Neil Brown wrote:
> >
> > The point is that the server's maximum is too low, [...]
>
> Why didn't you say so then (or did you and I missed it?).
Sorry, just being obscure ;-)
> The code in 2.4 is not ready to cope well with larger NFS packets. [...]
> For a 32k write, that means a
> kmalloc(32768) has to succeed, and very often free memory is too
> fragmented for it to succeed.
>
> For tcp, the request will be copied into a pre-allocated buffer. The
> (large) buffer is allocated when the nfsd thread is started,[...]
Ok, so if physical memory fragmentation is the only issue I'll just
try it. With 16K pages the allocation orders will be more reasonable.
> 2.6 copes with page-lists and so can handle requests and replies that
> are not cntiguous in memory, so this is not an issue and MAXBLKSIZE
> can safely be increased.
Excellent, this sounds like it deals with my long-term issue.
> I suggest that you simply recompile the kernel with a larger
> NFSSVC_MAXBLKSIZE and see how well it works.
> I can see no reasonable for having different values for udp and tcp
> though. Just make it uniformly 32768 and see how it goes.
How about I conditionally define NFSSVC_MAXBLKSIZE to 32k if the
page size is sufficently large? Would such a patch make it into 2.4?
Greg.
--
Greg Banks, R&D Software Engineer, SGI Australian Software Group.
I don't speak for SGI.
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next prev parent reply other threads:[~2003-11-27 1:34 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-11-25 17:34 Different NFSSVC_MAXBLKSIZE for udp and tcp clients? James Pearson
2003-11-26 1:08 ` Greg Banks
2003-11-26 1:40 ` Trond Myklebust
2003-11-26 1:51 ` Greg Banks
2003-11-26 2:00 ` Trond Myklebust
2003-11-26 10:43 ` James Pearson
2003-11-26 22:15 ` Neil Brown
2003-11-27 0:21 ` Greg Banks
2003-11-27 0:35 ` Neil Brown
2003-11-27 1:33 ` Greg Banks [this message]
-- strict thread matches above, loose matches on Subject: below --
2003-11-26 14:20 Lever, Charles
2003-11-27 0:08 ` Greg Banks
2003-11-27 0:53 ` Trond Myklebust
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