From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Subject: Re: Network throughput limits for local VM <-> VM communication Date: Wed, 10 Jun 2009 15:29:46 +0200 Message-ID: <200906101529.47103.arnd@arndb.de> References: <0199E0D51A61344794750DC57738F58E67D2398F9E@GVW1118EXC.americas.hpqcorp.net> <1244554780.11883.21.camel@blaa> <0199E0D51A61344794750DC57738F58E67D2399160@GVW1118EXC.americas.hpqcorp.net> Mime-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Cc: Mark McLoughlin , "kvm@vger.kernel.org" To: "Fischer, Anna" Return-path: Received: from moutng.kundenserver.de ([212.227.126.186]:54043 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755918AbZFJN3t (ORCPT ); Wed, 10 Jun 2009 09:29:49 -0400 In-Reply-To: <0199E0D51A61344794750DC57738F58E67D2399160@GVW1118EXC.americas.hpqcorp.net> Sender: kvm-owner@vger.kernel.org List-ID: On Tuesday 09 June 2009, Fischer, Anna wrote: > I have tried using virtio and using the emulated QEMU virtual NICs. > It does not make a difference. It seems as if there is an overflow somewhere > when QEMU/virtio cannot cope with the network load any more, and then the > virtual interfaces don't seem to transmit anything anymore. It seems to > mostly work again when I shut down and start up the interfaces of the router > inside of the guest. I use two bridges (and VLANs) that pass packets between > sending/receiving guests and the routing guest. The set-up works fine for > simple ping and other communication that is low-throughput type traffic. Have you tried eliminating VLAN to simplify the setup? Does it change when the guests communicate over a -net socket interface with your router instead of the -net tap + bridge in the host? Arnd <><