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From: "Ed Swierk" <eswierk@arastra.com>
To: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] Fastest TCP/IP Stack
Date: Thu, 14 Sep 2006 09:54:50 -0700	[thread overview]
Message-ID: <c1bf1cf0609140954g38c14e90v148c1506a467128@mail.gmail.com> (raw)
In-Reply-To: <200609140950.19475.it@tidetamerboatlifts.com>

On 9/14/06, Joseph Miller <it@tidetamerboatlifts.com> wrote:
> I'm running a terminal server under qemu with kqemu compiled into my kernel
> under the -kernel-kqemu for fastest performance.  What is the most efficient
> method of -net ?  I was using -net user with OpenVPN to connect to my
> internal LAN, but I have switched to -net tap to see if that is faster.  Does
> anyone have any knowledge of which would take the least overhead?  I noticed
> on my top stats that my % sys was particularly high when using networking
> under -net user.  Thanks

-net tap is considerably more efficient than -net user in most cases.
-net user is a TCP/UDP proxy, so (a) your TCP connections are no
longer end-to-end, and (b) performance is at the mercy of qemu's
internal TCP/IP stack. With -net tap and a bridge, IP packets are
passed along unmolested, and all the magic occurs within the host
kernel.

(Of course where performance is not a pressing issue, -net user is
still awfully convenient.)

--Ed

      parent reply	other threads:[~2006-09-14 16:54 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-09-14 13:50 [Qemu-devel] Fastest TCP/IP Stack Joseph Miller
2006-09-14 15:21 ` WaxDragon
2006-09-14 16:54 ` Ed Swierk [this message]

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