From owner-freebsd-current@FreeBSD.ORG Mon Jan 22 09:44:53 2007 Return-Path: X-Original-To: freebsd-current@freebsd.org Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 8CA1616A401 for ; Mon, 22 Jan 2007 09:44:53 +0000 (UTC) (envelope-from pyunyh@gmail.com) Received: from wr-out-0506.google.com (wr-out-0506.google.com [64.233.184.232]) by mx1.freebsd.org (Postfix) with ESMTP id 4940213C465 for ; Mon, 22 Jan 2007 09:44:53 +0000 (UTC) (envelope-from pyunyh@gmail.com) Received: by wr-out-0506.google.com with SMTP id 71so656516wri for ; Mon, 22 Jan 2007 01:44:52 -0800 (PST) DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:date:from:to:cc:subject:message-id:reply-to:references:mime-version:content-type:content-disposition:in-reply-to:user-agent; b=QFC/88MucOE7duSZ/jSSNY3oCu3Mj3KtChrNbnMwnd/E7LiY+HQ5cm8EkIy9jNnDAIry/9RdRyJNnQTwJtaWik3F3R9Y48XW3Vnfb93A9yEGAQiIyo4YIDjD9uDI/LSyMY7eOYER6yyvifGOcGgv1K7DGZnSr8nyI4ra9xgiX5g= Received: by 10.90.94.2 with SMTP id r2mr5875883agb.1169459092475; Mon, 22 Jan 2007 01:44:52 -0800 (PST) Received: from michelle.cdnetworks.co.kr ( [211.53.35.84]) by mx.google.com with ESMTP id 10sm9251392wrl.2007.01.22.01.44.50; Mon, 22 Jan 2007 01:44:51 -0800 (PST) Received: from michelle.cdnetworks.co.kr (localhost.cdnetworks.co.kr [127.0.0.1]) by michelle.cdnetworks.co.kr (8.13.5/8.13.5) with ESMTP id l0M9jp21030999 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Mon, 22 Jan 2007 18:45:51 +0900 (KST) (envelope-from pyunyh@gmail.com) Received: (from yongari@localhost) by michelle.cdnetworks.co.kr (8.13.5/8.13.5/Submit) id l0M9joTe030998; Mon, 22 Jan 2007 18:45:50 +0900 (KST) (envelope-from pyunyh@gmail.com) Date: Mon, 22 Jan 2007 18:45:50 +0900 From: Pyun YongHyeon To: Sepherosa Ziehau Message-ID: <20070122094550.GE29223@cdnetworks.co.kr> References: <20070122073611.GC29223@cdnetworks.co.kr> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.1i Cc: freebsd-current@freebsd.org Subject: Re: Call for re(4) checksum offload testers. X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: pyunyh@gmail.com List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 22 Jan 2007 09:44:53 -0000 On Mon, Jan 22, 2007 at 05:24:54PM +0800, Sepherosa Ziehau wrote: > On 1/22/07, Pyun YongHyeon wrote: > >Hi, > > > >It seems that some revisions of re(4) hardwares(PCIe variants?) still > >have Tx checksum offload issues. One user reported the issue said > >the attached patch fixed the issue on his box. > > -#define RL_MIN_FRAMELEN 60 > +/* > + * re(4) hardware IPv4 Tx checksum offload could be mangled with 28 bytes > + * or less IP packets. > + */ > +#define RL_TXCSUM_MINLEN 28 > +#define RL_MIN_FRAMELEN (ETHER_HDR_LEN + RL_TXCSUM_MINLEN) > > Does you patch mean a buggy PCIe re(4) will trash small packets padded > to 60bytes but will not trash small packets padded to 42bytes? If Yes. > "yes" is the answer, then why normal packets whose size is 60bytes > will not be trashed by a buggy PCIe re(4)? > I don't know(Only RealTek knows the details). But it seems that hardware's SM for checksum computation was confused by the padding bytes and subsequent small (retransmitted) packets which has less than a threshold frame length bytes were mangled. Maybe it didn't see extra padding bytes so its SM worked as expected. > IMHO, "fixing buggy PCIe re(4) txcsum" is not NetBSD's original > intention to narrow down the size of packets that will trigger the > re(4) txcsum bug. > Agreed. But it also fixed buggy checksum bugs in PCIe variants which does not like to expect extra padded bytes. > Best Regards, > sephe > > -- > Live Free or Die -- Regards, Pyun YongHyeon