From: "J. Bruce Fields" <bfields@fieldses.org>
To: NeilBrown <neilb@suse.de>
Cc: peter.staubach@emc.com, Trond.Myklebust@netapp.com,
bjschuma@netapp.com, linux-nfs@vger.kernel.org
Subject: Re: Use of READDIRPLUS on large directories
Date: Thu, 17 Mar 2011 13:44:53 -0400 [thread overview]
Message-ID: <20110317174453.GC30180@fieldses.org> (raw)
In-Reply-To: <20110317115522.29020461@notabene.brown>
On Thu, Mar 17, 2011 at 11:55:22AM +1100, NeilBrown wrote:
> Strangely, when I try NFSv4 I don't get what I would expect.
>
> "ls" on an unpatched 2.6.38 takes over 5 seconds rather than around 4.
> With the patch it does back down to about 2. (still NFSv3 at 1.5).
> Why would NFSv4 be slower?
> On v3 we make 44 READDIRPLUS calls and 284 READDIR calls - total of 328
> READDIRPLUS have about 30 names, READDIR have about 100
> On v4 we make 633 READDIR calls - nearly double.
> Early packed contain about 19 name, later ones about 70
>
> Is nfsd (2.6.32) just not packing enough answers in the reply?
> Client asks for a dircount of 16384 and a maxcount of 32768, and gets
> packets which are about 4K long - I guess that is PAGE_SIZE ??
>From nfsd4_encode_readdir():
maxcount = PAGE_SIZE;
if (maxcount > readdir->rd_maxcount)
maxcount = readdir->rd_maxcount;
Unfortunately, I don't think the xdr encoding is equipped to deal with
page boundaries. It should be.
--b.
next prev parent reply other threads:[~2011-03-17 17:44 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-16 4:55 Use of READDIRPLUS on large directories NeilBrown
2011-03-16 12:30 ` peter.staubach
2011-03-16 13:50 ` Trond Myklebust
2011-03-16 21:40 ` NeilBrown
2011-03-17 0:55 ` NeilBrown
2011-03-17 17:44 ` J. Bruce Fields [this message]
2011-03-18 4:27 ` NeilBrown
2011-03-16 13:43 ` Chuck Lever
2011-03-16 14:14 ` Bryan Schumaker
2011-03-16 14:20 ` Trond Myklebust
2011-03-16 21:30 ` NeilBrown
2011-03-16 21:42 ` Trond Myklebust
2011-03-16 22:40 ` NeilBrown
2011-03-17 17:18 ` J. Bruce Fields
2011-04-04 20:14 ` Bryan Schumaker
2011-04-05 12:20 ` NeilBrown
2011-04-07 14:28 ` Bryan Schumaker
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