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From: "J. Bruce Fields" <bfields@fieldses.org>
To: Chuck Lever <chuck.lever@oracle.com>
Cc: Jeff Layton <jlayton@redhat.com>, linux-nfs@vger.kernel.org
Subject: Re: [PATCH RFC] nfsd: report length of the largest hash chain in reply cache stats
Date: Sun, 17 Feb 2013 11:00:56 -0500	[thread overview]
Message-ID: <20130217160056.GC11441@fieldses.org> (raw)
In-Reply-To: <BA5562CC-9236-4EC1-BC7A-341387B9F452@oracle.com>

On Sat, Feb 16, 2013 at 12:18:18PM -0500, Chuck Lever wrote:
> 
> On Feb 16, 2013, at 8:39 AM, J. Bruce Fields <bfields@fieldses.org> wrote:
> > With a per-client maximum number of entries, sizing the hash tables
> > should be easier.
> When a server has only one client, should that client be allowed to
> maximize the use of a server's resources (eg, use all of the DRC
> resource the server has available)?

I've been assuming there's rapidly diminishing returns to caching a lot
of replies to a single client.  But that might not be true--I guess a
busy UDP client with a long retry timeout might benefit from a large
cache?

> How about when a server has one active client and multiple quiescent
> clients?

I think there's a chance in that case that one of the quiescent clients
is experiencing a temporary network problem, in which case we may want
to preserve a few entries for them even if the active client's activity
would normally evict them.

--b.

  reply	other threads:[~2013-02-17 16:00 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-02-15 17:23 [PATCH v2 0/3] nfsd: better stats gathering for DRC Jeff Layton
2013-02-15 17:23 ` [PATCH v2 1/3] nfsd: break out comparator into separate function Jeff Layton
2013-02-15 17:23 ` [PATCH v2 2/3] nfsd: track memory utilization in the DRC Jeff Layton
2013-02-15 17:23 ` [PATCH v2 3/3] nfsd: add new reply_cache_stats file in nfsdfs Jeff Layton
2013-02-15 17:29   ` Chuck Lever
2013-02-15 18:34     ` Jeff Layton
2013-02-15 20:04       ` [PATCH RFC] nfsd: report length of the largest hash chain in reply cache stats Jeff Layton
2013-02-15 21:14         ` Chuck Lever
2013-02-15 22:20           ` Jeff Layton
2013-02-16 13:39             ` J. Bruce Fields
2013-02-16 17:18               ` Chuck Lever
2013-02-17 16:00                 ` J. Bruce Fields [this message]
2013-02-17 19:58                   ` Chuck Lever
2013-02-18 14:21                   ` Jeff Layton
2013-02-18 14:30                     ` J. Bruce Fields
2013-02-18 14:39                 ` Jeff Layton
2013-02-18 16:18                   ` Chuck Lever

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