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From: Anthony Liguori <anthony@codemonkey.ws>
To: Paul Brook <paul@codesourcery.com>
Cc: nbd-general@lists.sourceforge.net, "Ciprian Dorin,
	Craciun" <ciprian.craciun@gmail.com>,
	linux-newbie@vger.kernel.org, qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] Transforming stdin and stdout pair into a socket
Date: Mon, 11 May 2009 21:24:26 -0500	[thread overview]
Message-ID: <4A08DDDA.309@codemonkey.ws> (raw)
In-Reply-To: <200905120007.24881.paul@codesourcery.com>

Paul Brook wrote:
>>     I've seen socat, and I could use it as you described. My only
>> objection to this solution is that there is an unneeded process in the
>> middle that just pipes data around...
>>
>>    (Instead of socat, I think it would be more efficient to just write
>> a simple application that uses the "new" Linux syscall "splice" that
>> I've just found by mistake yesterday...)
>>     
>
> In that case you need to fix socat to use splice() when available. I have a 
> hard time believing socat adds measurable overhead, especially if you're 
> already tunnelling over ssh.
>   

splice() doesn't really buy you anything when copying from a socket to 
another socket.  The data is going to get copied just like it would if 
you dropped to userspace.  It's useful if you introduce pipe-to-pipe 
copies because they'll be eliminated but if you're going from socket -> 
pipe -> socket it'll be the same as using socat.

Regards,

Anthony Liguori
> Paul
>   

      reply	other threads:[~2009-05-12  2:24 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-05-10 18:19 [Qemu-devel] Transforming stdin and stdout pair into a socket Ciprian Dorin, Craciun
2009-05-11  8:03 ` [Qemu-devel] Re: [Nbd] " Laurent Vivier
2009-05-11 13:28   ` Ciprian Dorin, Craciun
2009-05-11 12:02 ` [Qemu-devel] " Anthony Liguori
2009-05-11 13:32   ` Ciprian Dorin, Craciun
2009-05-11 19:31     ` [Nbd] " Wouter Verhelst
2009-05-11 23:07     ` Paul Brook
2009-05-12  2:24       ` Anthony Liguori [this message]

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