From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:52284) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZEbqV-0000g5-Ea for qemu-devel@nongnu.org; Mon, 13 Jul 2015 07:24:28 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZEbqQ-0005P4-8W for qemu-devel@nongnu.org; Mon, 13 Jul 2015 07:24:27 -0400 Received: from mx1.redhat.com ([209.132.183.28]:47607) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZEbqQ-0005Or-2E for qemu-devel@nongnu.org; Mon, 13 Jul 2015 07:24:22 -0400 References: <20150702012121.GA4477@ad.nay.redhat.com> <20150708173423-mutt-send-email-mst@redhat.com> <20150709132248.GA12399@stefanha-thinkpad.redhat.com> <20150709162723-mutt-send-email-mst@redhat.com> <55A39047.5070806@redhat.com> <20150713141421-mutt-send-email-mst@redhat.com> From: Paolo Bonzini Message-ID: <55A39FDF.1060800@redhat.com> Date: Mon, 13 Jul 2015 13:24:15 +0200 MIME-Version: 1.0 In-Reply-To: <20150713141421-mutt-send-email-mst@redhat.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] virtio-blk multiqueue support in qemu. List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Michael S. Tsirkin" Cc: Naredula Janardhana Reddy , Fam Zheng , Stefan Hajnoczi , Ming Lei , qemu-devel@nongnu.org, Stefan Hajnoczi On 13/07/2015 13:21, Michael S. Tsirkin wrote: > > Yes, this is already how virtio-scsi multiqueue is implemented. The > > speedup is noticeable. However, for virtio-blk there is a huge > > consumption of interrupt vectors in the guest, so it doesn't scale to > > multiple disks as well as virtio-scsi. > > Could you elaborate please? interrupt vector usage is generally > up to the guest, so whatever the issue is might be fixable by driver > changes alone. Yes, but in practice neither Linux nor Windows (AFAIK) are able to share the same vector across multiple MSIs. Paolo