From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rusty Russell Subject: Re: virtio specification: OOO completion of the xmit buffers in the networking device Date: Wed, 04 Jun 2014 13:22:49 +0930 Message-ID: <871tv549gu.fsf@rustcorp.com.au> References: <538C7D2D.8080508@cloudius-systems.com> Mime-Version: 1.0 Content-Type: text/plain Cc: "Michael S. Tsirkin" To: Vlad Zolotarov , kvm@vger.kernel.org Return-path: Received: from ozlabs.org ([103.22.144.67]:48198 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750717AbaFDEJh (ORCPT ); Wed, 4 Jun 2014 00:09:37 -0400 In-Reply-To: <538C7D2D.8080508@cloudius-systems.com> Sender: kvm-owner@vger.kernel.org List-ID: Vlad Zolotarov writes: > Rusty, hi! > I'd like to ask for a small clarification about the virtio spec. > The virtio specification is put the way that it allows the out-of-order > completions in general. Although it states that it's mostly relevant to > the virtio-blk it doesn't explicitly bans it for virtio networking > devices (for generality?). Indeed. > (AFAICS the current virtio HV implementations make sure there is no OOO > Tx buffers completions). > > I wonder if this feature (OOO Tx buffers completions) seems practical to > u and if not can I hope that it could be clearly stated in the future > virtio specification releases that it's forbidden? Are you sure that vhost-net doesn't allow async completion already? I can't immediately see why it can't happen, but MST is CC'd. Cheers, Rusty.