From: Ben Greear <greearb@candelatech.com>
To: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: "linux-nfs@vger.kernel.org" <linux-nfs@vger.kernel.org>
Subject: Re: Reading NFS file without copying to user-space?
Date: Fri, 04 Sep 2009 14:57:06 -0700 [thread overview]
Message-ID: <4AA18D32.50507@candelatech.com> (raw)
In-Reply-To: <74C14419-4D21-4EC2-B01A-EAC04B354F06@fys.uio.no>
On 09/04/2009 01:58 PM, Trond Myklebust wrote:
> You're missing the point. O_DIRECT does not copy data from the kernel
> into userspace. The data is placed directly into the user buffer from
> the socket.
>
> The only faster alternative would be to directly discard the data in the
> socket, and we offer no option to do that.
I was thinking I might be clever and use sendfile to send an nfs
file to /dev/zero, but unfortunately it seems sendfile can only send
to a destination that is a socket....
Ben
--
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc http://www.candelatech.com
next prev parent reply other threads:[~2009-09-04 21:57 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-09-04 19:48 Reading NFS file without copying to user-space? Ben Greear
2009-09-04 20:35 ` Trond Myklebust
[not found] ` <1252096543.2402.4.camel-rJ7iovZKK19ZJLDQqaL3InhyD016LWXt@public.gmane.org>
2009-09-04 20:49 ` Ben Greear
2009-09-04 20:58 ` Trond Myklebust
2009-09-04 21:12 ` Ben Greear
2009-09-04 22:00 ` Trond Myklebust
2009-09-04 21:57 ` Ben Greear [this message]
2009-09-04 22:15 ` Trond Myklebust
[not found] ` <1252102506.5274.7.camel-rJ7iovZKK19ZJLDQqaL3InhyD016LWXt@public.gmane.org>
2009-09-04 22:30 ` Ben Greear
2009-09-04 22:49 ` Trond Myklebust
2009-09-04 23:03 ` Ben Greear
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