From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matheos Worku Subject: Re: [PATCH] [NIU] VLAN does not work with niu driver Date: Wed, 09 Sep 2009 18:19:00 -0700 Message-ID: <4AA85404.5020300@sun.com> References: <4AA819D8.1020306@Sun.COM> <20090909.171517.34998160.davem@davemloft.net> <4AA84FE3.6030407@sun.com> <20090909.181033.25374239.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; CHARSET=US-ASCII; format=flowed Content-Transfer-Encoding: 7BIT Cc: Joyce.Yu@Sun.COM, netdev@vger.kernel.org To: David Miller Return-path: Received: from sca-es-mail-1.Sun.COM ([192.18.43.132]:63298 "EHLO sca-es-mail-1.sun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751707AbZIJBUR (ORCPT ); Wed, 9 Sep 2009 21:20:17 -0400 Received: from fe-sfbay-09.sun.com ([192.18.43.129]) by sca-es-mail-1.sun.com (8.13.7+Sun/8.12.9) with ESMTP id n8A1KI4j013958 for ; Wed, 9 Sep 2009 18:20:18 -0700 (PDT) Received: from conversion-daemon.fe-sfbay-09.sun.com by fe-sfbay-09.sun.com (Sun Java(tm) System Messaging Server 7u2-7.04 64bit (built Jul 2 2009)) id <0KPQ00J00E6K6100@fe-sfbay-09.sun.com> for netdev@vger.kernel.org; Wed, 09 Sep 2009 18:20:18 -0700 (PDT) In-reply-to: <20090909.181033.25374239.davem@davemloft.net> Sender: netdev-owner@vger.kernel.org List-ID: David Miller wrote: > From: Matheos Worku > Date: Wed, 09 Sep 2009 18:01:23 -0700 > >> The frame type in NIU HW is embedded in a HW header, so it is possible >> to check the HW header and decide whether to pull up ETH_HLEN or VLAN >> header size of bytes. However, considering the amount of work required >> to get and examine the HW header (including endianess issues), we >> thought pulling up 64 bytes by default (as used in cassini.c) would be >> efficient. > > Well, it was 64 in early versions of the driver, and I decreased it > down to ETH_HLEN. > > The less the better since for forwarding applications anything past > the IPV4 header pulled is going to be a waste of CPU cache lines and > thus negatively effect forwarding rates. > > That's why I asked if this change was performance regression tested, > because I know it's going to slow down forwarding rates for small > packets. Dave, We did throughput testing (netperf) and didn't notice any performance degradation. We haven't done forwarding testing however. We can work on a version which implements HW header checking and do pullup accordingly. Regards, Matheos > -- > To unsubscribe from this list: send the line "unsubscribe netdev" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html