From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:50652) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TaRj3-0000uG-N6 for qemu-devel@nongnu.org; Mon, 19 Nov 2012 08:49:28 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TaRj0-0004YW-KU for qemu-devel@nongnu.org; Mon, 19 Nov 2012 08:49:25 -0500 Received: from ssl.dlhnet.de ([91.198.192.8]:35828 helo=ssl.dlh.net) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TaRj0-0004YF-Dg for qemu-devel@nongnu.org; Mon, 19 Nov 2012 08:49:22 -0500 Message-ID: <50AA38E1.4000405@dlhnet.de> Date: Mon, 19 Nov 2012 14:49:21 +0100 From: Peter Lieven MIME-Version: 1.0 References: <24E144B8C0207547AD09C467A8259F75577EC4B2@lisa.maurer-it.com> <509B7DC4.3010802@web.de> <24E144B8C0207547AD09C467A8259F75577EDCC2@lisa.maurer-it.com> <24E144B8C0207547AD09C467A8259F75577EE707@lisa.maurer-it.com> <6c17c45c1439f217b36df2c78f0a04e6.squirrel@ssl.dlhnet.de> <50A233AF.70107@dlhnet.de> <20121113162256.GA554@redhat.com> <20121113163331.GA645@redhat.com> In-Reply-To: <20121113163331.GA645@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] slow virtio network with vhost=on and multiple cores List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Michael S. Tsirkin" Cc: Stefan Hajnoczi , Peter Lieven , Jan Kiszka , Dietmar Maurer , "qemu-devel@nongnu.org" On 13.11.2012 17:33, Michael S. Tsirkin wrote: > On Tue, Nov 13, 2012 at 06:22:56PM +0200, Michael S. Tsirkin wrote: >> On Tue, Nov 13, 2012 at 12:49:03PM +0100, Peter Lieven wrote: >>> On 09.11.2012 19:03, Peter Lieven wrote: >>>> Remark: >>>> If i disable interrupts on CPU1-3 for virtio the performance is ok again. >>>> >>>> Now we need someone with deeper knowledge of the in-kernel irqchip and the >>>> virtio/vhost driver development to say if this is a regression in qemu-kvm >>>> or a problem with the old virtio drivers if they receive the interrupt on >>>> different CPUs. >>> anyone? >> Looks like the problem is not in the guest: I tried ubuntu guest >> on a rhel host, I got 8GB/s with vhost and 4GB/s without >> on a host to guest banchmark. >> > Tried with upstream qemu on rhel kernel and that's even a bit faster. > So it's ubuntu kernel. vanilla 2.6.32 didn't have vhost at all > so maybe their vhost backport is broken insome way. > Do you remember since which version of the vanilla kernel vhost-net was officially included? Peter