From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1N81rt-0002ui-7f for qemu-devel@nongnu.org; Tue, 10 Nov 2009 20:19:29 -0500 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1N81rm-0002ir-Os for qemu-devel@nongnu.org; Tue, 10 Nov 2009 20:19:27 -0500 Received: from [199.232.76.173] (port=37384 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1N81rm-0002iL-6E for qemu-devel@nongnu.org; Tue, 10 Nov 2009 20:19:22 -0500 Received: from mx20.gnu.org ([199.232.41.8]:59722) by monty-python.gnu.org with esmtps (TLS-1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1N81rl-000081-UL for qemu-devel@nongnu.org; Tue, 10 Nov 2009 20:19:22 -0500 Received: from mail.codesourcery.com ([38.113.113.100]) by mx20.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1N81rk-0003yH-VZ for qemu-devel@nongnu.org; Tue, 10 Nov 2009 20:19:21 -0500 From: Paul Brook Subject: Re: [Qemu-devel] net packet storms with multiple NICs Date: Wed, 11 Nov 2009 01:19:18 +0000 References: <4AE1D903.5030709@msgid.tls.msk.ru> In-Reply-To: <4AE1D903.5030709@msgid.tls.msk.ru> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <200911110119.18839.paul@codesourcery.com> List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Michael Tokarev , KVM list > I immediately reproduced the problem locally. It turns out that > kvm reflects packets coming from one guest NIC on another guest > NIC, and since both are connected to the same bridge we're getting > endless packet storm. To a level when kvm process becomes 100% > busy and does not respond to anything but `kill -9'. You created a network loop. It is working exactly as expected. Create the same topology with a physical network hub and a pair of NICs and you'll get the same end result. Paul