From owner-svn-src-head@FreeBSD.ORG Wed Jun 5 06:00:12 2013 Return-Path: Delivered-To: svn-src-head@FreeBSD.org Received: from mx1.freebsd.org (mx1.FreeBSD.org [8.8.178.115]) by hub.freebsd.org (Postfix) with ESMTP id 09FD3C77; Wed, 5 Jun 2013 06:00:12 +0000 (UTC) (envelope-from lstewart@freebsd.org) Received: from lauren.room52.net (lauren.room52.net [210.50.193.198]) by mx1.freebsd.org (Postfix) with ESMTP id C5AF315DB; Wed, 5 Jun 2013 06:00:11 +0000 (UTC) Received: from lstewart.caia.swin.edu.au (lstewart.caia.swin.edu.au [136.186.229.95]) by lauren.room52.net (Postfix) with ESMTPSA id 8FCF57E81E; Wed, 5 Jun 2013 15:51:47 +1000 (EST) Message-ID: <51AED1F3.2060003@freebsd.org> Date: Wed, 05 Jun 2013 15:51:47 +1000 From: Lawrence Stewart User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:17.0) Gecko/20130521 Thunderbird/17.0.6 MIME-Version: 1.0 To: Andre Oppermann Subject: Re: svn commit: r251297 - head/sys/dev/xen/netfront References: <201306031300.r53D0XUx092178@svn.freebsd.org> In-Reply-To: <201306031300.r53D0XUx092178@svn.freebsd.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=0.0 required=5.0 tests=UNPARSEABLE_RELAY autolearn=unavailable version=3.3.2 X-Spam-Checker-Version: SpamAssassin 3.3.2 (2011-06-06) on lauren.room52.net Cc: svn-src-head@FreeBSD.org, svn-src-all@FreeBSD.org, src-committers@FreeBSD.org, cperciva@FreeBSD.org X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 05 Jun 2013 06:00:12 -0000 On 06/03/13 23:00, Andre Oppermann wrote: > Author: andre > Date: Mon Jun 3 13:00:33 2013 > New Revision: 251297 > URL: http://svnweb.freebsd.org/changeset/base/251297 > > Log: > Specify a maximum TSO length limiting the segment chain to what the > Xen host side can handle after defragmentation. > > This prevents the driver from throwing away too long TSO chains and > improves the performance on Amazon AWS instances with 10GigE virtual > interfaces to the normally expected throughput. > > Submitted by: cperciva (earlier version) > Reviewed by: cperciva > Tested by: cperciva > MFC after: 1 week > > Modified: > head/sys/dev/xen/netfront/netfront.c > > Modified: head/sys/dev/xen/netfront/netfront.c > ============================================================================== > --- head/sys/dev/xen/netfront/netfront.c Mon Jun 3 12:55:13 2013 (r251296) > +++ head/sys/dev/xen/netfront/netfront.c Mon Jun 3 13:00:33 2013 (r251297) > @@ -134,6 +134,7 @@ static const int MODPARM_rx_flip = 0; > * to mirror the Linux MAX_SKB_FRAGS constant. > */ > #define MAX_TX_REQ_FRAGS (65536 / PAGE_SIZE + 2) > +#define NF_TSO_MAXBURST ((IP_MAXPACKET / PAGE_SIZE) * MCLBYTES) For posterity's sake, can you and/or Colin please elaborate on how this value was determined and what it is dependent upon? Could a newer version of Xen remove the need for this reduced limit? Cheers, Lawrence