From mboxrd@z Thu Jan 1 00:00:00 1970 From: Shirley Ma Subject: Re: [PATCH RFC] tun: experimental zero copy tx support Date: Mon, 14 May 2012 10:34:50 -0700 Message-ID: <1337016890.3851.20.camel@oc3660625478.ibm.com> References: <20120513155206.GA26847@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: "David S. Miller" , Stephen Hemminger , Joe Perches , Jason Wang , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Ian.Campbell@citrix.com, kvm@vger.kernel.org To: "Michael S. Tsirkin" Return-path: Received: from e32.co.us.ibm.com ([32.97.110.150]:42368 "EHLO e32.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932085Ab2ENRfg (ORCPT ); Mon, 14 May 2012 13:35:36 -0400 Received: from /spool/local by e32.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 14 May 2012 11:35:35 -0600 In-Reply-To: <20120513155206.GA26847@redhat.com> Sender: netdev-owner@vger.kernel.org List-ID: On Sun, 2012-05-13 at 18:52 +0300, Michael S. Tsirkin wrote: > Let vhost-net utilize zero copy tx when the experimental > zero copy mode is enabled and when used with tun. This works on > top of the patchset 'copy aside frags with destructors' that I posted > previously. This is not using tcp so doesn't have the > issue with early skb cloning noticed by Ian. > > For those that wish to test this with kvm, I intend to post a patchset > + > git tree with just the necessary bits from the destructor patch > a bit later. > > Signed-off-by: Michael S. Tsirkin Hello Mike, Have you tested this patch? I think the difference between macvtap and tap is tap forwarding the packet to bridge. The zerocopy is disabled in this case. Shirley