From owner-freebsd-hackers Tue Jun 20 15:24:33 2000 Delivered-To: freebsd-hackers@freebsd.org Received: from kbgroup.co.nz (gateway.kbgroup.co.nz [203.96.151.81]) by hub.freebsd.org (Postfix) with ESMTP id 396EE37B543 for ; Tue, 20 Jun 2000 15:24:30 -0700 (PDT) (envelope-from dave.preece@kbgroup.co.nz) Received: from kb_exchange.kbgroup.co.nz ([202.202.203.10]) by gateway.kbgroup.co.nz with ESMTP id <115201>; Wed, 21 Jun 2000 10:41:37 +1200 Received: by internet.kbgroup.co.nz with Internet Mail Service (5.5.2650.21) id ; Wed, 21 Jun 2000 10:33:55 +1200 Message-ID: <67B808B0DD93D211ABEE0000B498356B02BCCF@internet.kbgroup.co.nz> From: Dave Preece To: freebsd-hackers@freebsd.org Subject: IP checksum offloading with intel 82559 fast ethernet. MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2650.21) Content-Type: text/plain; charset="iso-8859-1" Date: Wed, 21 Jun 2000 10:41:28 +1200 Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG Apparently (http://developer.intel.com/design/network/82559.htm) the i82559 can offload TCP and UDP checksums. A quick peruse of /usr/src/sys/pci/if_fxp.c shows we are not currently using this - which is fair enough since the driver also has to work with 82557 and 82558. It strikes me that due to the driver architecture (i.e. the IP packet is formed way before it gets to ip_fxp) that we couldn't use this facility - even if it does have some potentially excellent throughput implications. Maybe there's a possibility for treating it as an IP accelerating 'co-processor' (much as the early power vr 3d accelerators did). Any comments? Anyone working on this? Maybe I had better learn to write drivers ;) Dave To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message