From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1GNuUI-0004tS-8A for qemu-devel@nongnu.org; Thu, 14 Sep 2006 12:54:54 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1GNuUG-0004tG-Rd for qemu-devel@nongnu.org; Thu, 14 Sep 2006 12:54:52 -0400 Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1GNuUG-0004tD-LJ for qemu-devel@nongnu.org; Thu, 14 Sep 2006 12:54:52 -0400 Received: from [66.249.82.225] (helo=wx-out-0506.google.com) by monty-python.gnu.org with esmtp (Exim 4.52) id 1GNuWF-0002f6-Ds for qemu-devel@nongnu.org; Thu, 14 Sep 2006 12:56:55 -0400 Received: by wx-out-0506.google.com with SMTP id r21so3225084wxc for ; Thu, 14 Sep 2006 09:54:51 -0700 (PDT) Message-ID: Date: Thu, 14 Sep 2006 09:54:50 -0700 From: "Ed Swierk" Sender: eswierk@gmail.com Subject: Re: [Qemu-devel] Fastest TCP/IP Stack In-Reply-To: <200609140950.19475.it@tidetamerboatlifts.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <200609140950.19475.it@tidetamerboatlifts.com> Reply-To: qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org On 9/14/06, Joseph Miller 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