From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751206Ab3GXEmJ (ORCPT ); Wed, 24 Jul 2013 00:42:09 -0400 Received: from mx1.redhat.com ([209.132.183.28]:12859 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750865Ab3GXEmH (ORCPT ); Wed, 24 Jul 2013 00:42:07 -0400 Message-ID: <51EF5B00.7040109@redhat.com> Date: Wed, 24 Jul 2013 12:41:36 +0800 From: Jason Wang User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130623 Thunderbird/17.0.7 MIME-Version: 1.0 To: Stephen Hemminger CC: davem@davemloft.net, mst@redhat.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Basil Gor Subject: Re: [PATCH net-next] tuntap: hardware vlan tx support References: <1374563748-38821-1-git-send-email-jasowang@redhat.com> <20130723081727.69766d27@nehalam.linuxnetplumber.net> In-Reply-To: <20130723081727.69766d27@nehalam.linuxnetplumber.net> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/23/2013 11:17 PM, Stephen Hemminger wrote: > On Tue, 23 Jul 2013 15:15:48 +0800 > Jason Wang wrote: > >> Inspired by commit f09e2249c4f5c7c13261ec73f5a7807076af0c8e (macvtap: restore >> vlan header on user read). This patch adds hardware vlan tx support for >> tuntap. This is done by copying vlan header directly into userspace in >> tun_put_user() instead of doing it through __vlan_put_tag() in >> dev_hard_start_xmit(). This eliminates one unnecessary memove in >> vlan_insert_tag() for 802.1ad and 802.1q traffic. >> >> pktgen test shows about 20% improvement for 802.1q traffic: >> >> Before: >> 662149pps 317Mb/sec (317831520bps) errors: 0 >> After: >> 801033pps 384Mb/sec (384495840bps) errors: 0 >> >> Cc: Basil Gor >> Cc: Michael S. Tsirkin >> Signed-off-by: Jason Wang > > You need to make this configurable by some mechanism, since otherwise > it will break applications that expect current VLAN behavior > -- > Didn't see any breakage. Vlan id will always exist in the userspace buffer.