linux-kernel - Re: slow open() calls and o

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Date:	Mon, 4 Jun 2007 11:20:55 +1000
From:	Neil Brown <neilb@...e.de>
To:	"Aaron Wiebe" <epiphani@...il.com>
Cc:	linux-kernel@...r.kernel.org, "John Stoffel" <john@...ffel.org>
Subject: Re: slow open() calls and o_nonblock

On Sunday June 3, epiphani@...il.com wrote:
> 
> You can certainly open the file, but not block on the call to do it.
> What confuses me is why the kernel would "block" for 415ms on an open
> call.  Thats an eternity to suspend a process that has to distribute
> data such as this.

Have you tried the "nocto" mount option for your NFS filesystems.

The cache-coherency rules of NFS require the client to check with the
server at each open.  If you are the sole client on this filesystem,
then you don't need the same cache-coherency, and "nocto" will tell
the NFS client not to both checking with the server in information is
available in cache.

This should speed up the time for open considerably.

NeilBrown
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