From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753533Ab0INMLy (ORCPT ); Tue, 14 Sep 2010 08:11:54 -0400 Received: from mx1.redhat.com ([209.132.183.28]:1027 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751999Ab0INMLv (ORCPT ); Tue, 14 Sep 2010 08:11:51 -0400 Date: Tue, 14 Sep 2010 14:05:45 +0200 From: "Michael S. Tsirkin" To: Shirley Ma Cc: Avi Kivity , Arnd Bergmann , xiaohui.xin@intel.com, netdev@vger.kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH 0/1] macvtap TX zero copy between guest and host kernel Message-ID: <20100914120545.GC703@redhat.com> References: <1284410580.13351.10.camel@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1284410580.13351.10.camel@localhost.localdomain> User-Agent: Mutt/1.5.20 (2009-12-10) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Sep 13, 2010 at 01:43:00PM -0700, Shirley Ma wrote: > This patch induces a new sock flag ZEROCOPY to avoid copy between > userspace and kernel. macvtap is the first user of zero copy between > guest and host kernel. It only uses when the lower device supports high > memory DMA. The first set of patch only addresses transmission TX side. > The test has shown big improvement on either CPU utilization reduction > or BW increase on 10GbE Intel NIC. Performance data will be submitted in > the coming email. > > thanks > Shirley While others pointed out correctness issues with the patch, I would still like to see the performance numbers, just so we understand what's possible. -- MST