linux-kernel - Re: 2.6.31-rc8: CIFS with 5 seconds hiccups

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Message-ID: <20090910153347.2f2616e8@barsoom.rdu.redhat.com>
Date:	Thu, 10 Sep 2009 15:33:47 -0400
From:	Jeff Layton <jlayton@...hat.com>
To:	Christoph Lameter <cl@...ux-foundation.org>
Cc:	linux-kernel@...r.kernel.org, samba@...ts.samba.org,
	linux-cifs-client@...ts.samba.org
Subject: Re: 2.6.31-rc8: CIFS with 5 seconds hiccups

On Thu, 10 Sep 2009 14:53:12 -0400 (EDT)
Christoph Lameter <cl@...ux-foundation.org> wrote:

> On Wed, 9 Sep 2009, Jeff Layton wrote:
> 
> > Well, I can see the delays in the capture, but the snarflen for the
> > capture is a little too small to tell much else. Can you redo the
> > capture with a larger snarflen (maybe -s 512 or so)?
> 
> -s 1000 version attached.
> 
> > Also, were you able to tell anything from a server-side capture? Is the
> > server issuing oplock breaks at those times?
> 
> Thats a pretty busy system. They have not gotten around to do any logging
> on that end.

Ok. I had a look at the capture. The stalls seem to be occurring on
FIND_FILE requests. Those are similar to READDIRPLUS requests in NFS,
it returns a list of files that match a particular set of criteria and
their attributes.

Each time the client is making one of these calls to the server, it
requests a set of up to 150 files. The server grinds for 5s each time
and then responds.

The calls themselves seem to be sane AFAICT. I don't see any problems
with the parameters we're sending for the search. I also had a look
over the FIND_FIRST code and it doesn't seem to have any obvious
word size related problems.

I assume that the 32 and 64 bit clients you have are calling "ls" in
the same dir. If so, maybe a similar capture from a 64-bit client might
help us see the difference?

Thanks,
-- 
Jeff Layton <jlayton@...hat.com>
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