Received: with ECARTIS (v1.0.0; list netdev); Fri, 13 Jun 2003 15:50:39 -0700 (PDT) Received: from pizda.ninka.net (IDENT:root@pizda.ninka.net [216.101.162.242]) by oss.sgi.com (8.12.9/8.12.9) with SMTP id h5DMoS2x019554 for ; Fri, 13 Jun 2003 15:50:28 -0700 Received: from localhost (IDENT:davem@localhost.localdomain [127.0.0.1]) by pizda.ninka.net (8.9.3/8.9.3) with ESMTP id PAA03124; Fri, 13 Jun 2003 15:46:35 -0700 Date: Fri, 13 Jun 2003 15:46:34 -0700 (PDT) Message-Id: <20030613.154634.74748085.davem@redhat.com> To: anton@samba.org Cc: haveblue@us.ibm.com, hdierks@us.ibm.com, scott.feldman@intel.com, dwg@au1.ibm.com, linux-kernel@vger.kernel.org, milliner@us.ibm.com, ricardoz@us.ibm.com, twichell@us.ibm.com, netdev@oss.sgi.com Subject: Re: e1000 performance hack for ppc64 (Power4) From: "David S. Miller" In-Reply-To: <20030613223841.GB32097@krispykreme> References: <1055521263.3531.2055.camel@nighthawk> <20030613223841.GB32097@krispykreme> X-FalunGong: Information control. X-Mailer: Mew version 2.1 on Emacs 21.1 / Mule 5.0 (SAKAKI) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-archive-position: 3218 X-ecartis-version: Ecartis v1.0.0 Sender: netdev-bounce@oss.sgi.com Errors-to: netdev-bounce@oss.sgi.com X-original-sender: davem@redhat.com Precedence: bulk X-list: netdev From: Anton Blanchard Date: Sat, 14 Jun 2003 08:38:41 +1000 This is only worth it if most packets will have the same sized header. Networking guys: is this a valid assumption? Not really... one retransmit and the TCP header size grows due to the SACK options. I find it truly bletcherous what you're trying to do here. Why not instead find out if it's possible to have the e1000 fetch the entire cache line where the first byte of the packet resides? Even ancient designes like SunHME do that.