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From: Chuck Lever <chuck.lever@oracle.com>
To: Daniel J Blueman <daniel.blueman@gmail.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>,
	Al Viro <viro@zeniv.linux.org.uk>,
	linux-nfs@vger.kernel.org,
	Linux Kernel <linux-kernel@vger.kernel.org>
Subject: Re: [2.6.34-rc2 NFS4 oops] open error path failure...
Date: Wed, 31 Mar 2010 10:21:07 -0400	[thread overview]
Message-ID: <4BB35A53.5000003@oracle.com> (raw)
In-Reply-To: <w2s6278d2221003310420xd36fa9ey92b781fb9f4d1a10@mail.gmail.com>

On 03/31/2010 07:20 AM, Daniel J Blueman wrote:
> Talking of expensive, I see latencytop show>16000ms latency for
> writing pages when I have a workload that does large buffered I/O to
> an otherwise uncongested server. The gigabit network is saturated, and
> reads often stall for 1000-4000ms (!). Client has the default 16 TCP
> request slots, and server has 8 nfsds - the server is far from disk or
> processor-saturated. I'll see if there is any useful debugging I can
> get about this.

That latency is pretty much guaranteed to be due to a long RPC backlog 
queue on the client.  Bumping the size of the slot table to 128 and 
increasing the number of NFSD threads may help.

-- 
chuck[dot]lever[at]oracle[dot]com

  reply	other threads:[~2010-03-31 14:23 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-03-29 18:36 [2.6.34-rc2 NFS4 oops] open error path failure Daniel J Blueman
2010-03-29 19:03 ` Al Viro
2010-03-29 19:21   ` Daniel J Blueman
2010-03-29 21:22   ` Trond Myklebust
2010-03-31 11:20     ` Daniel J Blueman
2010-03-31 14:21       ` Chuck Lever [this message]
2010-04-02 10:34         ` Daniel J Blueman

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