From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754572AbZHQOXc (ORCPT ); Mon, 17 Aug 2009 10:23:32 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754445AbZHQOXb (ORCPT ); Mon, 17 Aug 2009 10:23:31 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:45310 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754341AbZHQOXa (ORCPT ); Mon, 17 Aug 2009 10:23:30 -0400 Date: Mon, 17 Aug 2009 16:23:10 +0200 From: Ingo Molnar To: Anthony Liguori Cc: Gregory Haskins , kvm@vger.kernel.org, Avi Kivity , alacrityvm-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, "Michael S. Tsirkin" Subject: Re: [PATCH v3 3/6] vbus: add a "vbus-proxy" bus model for vbus_driver objects Message-ID: <20090817142310.GA3602@elte.hu> References: <20090814154125.26116.70709.stgit@dev.haskins.net> <20090814154308.26116.46980.stgit@dev.haskins.net> <20090815103243.GA26749@elte.hu> <4A870964.9090408@codemonkey.ws> <20090816071607.GB29537@elte.hu> <4A896112.9030407@codemonkey.ws> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4A896112.9030407@codemonkey.ws> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.5 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Anthony Liguori wrote: > Ingo Molnar wrote: >>> I think the reason vbus gets better performance for networking today >>> is that vbus' backends are in the kernel while virtio's backends are >>> currently in userspace. Since Michael has a functioning in-kernel >>> backend for virtio-net now, I suspect we're weeks (maybe days) away >>> from performance results. My expectation is that vhost + virtio-net >>> will be as good as venet + vbus. If that's the case, then I don't >>> see any reason to adopt vbus unless Greg things there are other >>> compelling features over virtio. >>> >> >> Keeping virtio's backend in user-space was rather stupid IMHO. > > I don't think it's quite so clear. in such a narrow quote it's not so clear indeed - that's why i qualified it with: >> Having the _option_ to piggyback to user-space (for flexibility, >> extensibility, etc.) is OK, but not having kernel acceleration is >> bad. Ingo