From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53738) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZWi4m-000633-QN for qemu-devel@nongnu.org; Tue, 01 Sep 2015 05:42:05 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZWi4h-0001zW-OQ for qemu-devel@nongnu.org; Tue, 01 Sep 2015 05:42:00 -0400 Received: from mx1.redhat.com ([209.132.183.28]:33214) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZWi4h-0001zO-J1 for qemu-devel@nongnu.org; Tue, 01 Sep 2015 05:41:55 -0400 Date: Tue, 1 Sep 2015 12:41:49 +0300 From: "Michael S. Tsirkin" Message-ID: <20150901124105-mutt-send-email-mst@redhat.com> References: <1439360742-2186-1-git-send-email-changchun.ouyang@intel.com> <1439360742-2186-2-git-send-email-changchun.ouyang@intel.com> <20150813121013-mutt-send-email-mst@redhat.com> <20150827154430-mutt-send-email-mst@redhat.com> <20150830091225-mutt-send-email-mst@redhat.com> <20150831142809-mutt-send-email-mst@redhat.com> <20150901092006.GC3054@yliu-dev.sh.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150901092006.GC3054@yliu-dev.sh.intel.com> Subject: Re: [Qemu-devel] [snabb-devel] Re: [PATCH v6 1/2] vhost-user: add multi queue support List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Yuanhan Liu Cc: "snabb-devel@googlegroups.com" , "thibaut.collet@6wind.com" , "qemu-devel@nongnu.org" , "n.nikolaev@virtualopensystems.com" , "luke@snabb.co" , "Long, Thomas" , "Ouyang, Changchun" On Tue, Sep 01, 2015 at 05:20:06PM +0800, Yuanhan Liu wrote: > On Mon, Aug 31, 2015 at 02:30:06PM +0300, Michael S. Tsirkin wrote: > [snip..] > > > Then how about the other case: > > > When startup the vhost backend, user specify 8 queues, like: > > > Vhost-user ... -queues 8 # Y=8 > > > When startup the guest, user specify 4 queues, like: > > > Qemu-kvm ... -queues 4 # X=4 > > > > > > Vhost backend CAN support the queues number as much as the guest/qemu requires, > > > And qemu don't want enable all of them(8 in the case), just part of them(only 4 from 8). > > > Will qemu exit or go forward(of course with 4 queues)? > > > > I think it must go forward since guest does not have to > > configure all queues anyway - and that's built in to virtio spec. > > > > Note that # of queues in actual use in fact changes dynamically > > too, without restaring the device. > > May I know how do you do that? I mean, is there a public interface, like > by some commands? Or, by sending vhost messages? > > --yliu Using ethtool within guest. In fact, guests boot with a single queue, you need to use ethtool to enable mq, specifying the # of queues. -- MST