From owner-freebsd-stable Mon Dec 11 7:24:32 2000 From owner-freebsd-stable@FreeBSD.ORG Mon Dec 11 07:24:29 2000 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from pan.salford.ac.uk (pan.salford.ac.uk [146.87.255.104]) by hub.freebsd.org (Postfix) with SMTP id CBD0A37B400 for ; Mon, 11 Dec 2000 07:24:27 -0800 (PST) Received: (qmail 24060 invoked by alias); 11 Dec 2000 15:24:21 -0000 Received: (qmail 24054 invoked from network); 11 Dec 2000 15:24:21 -0000 Received: from unknown (HELO plato.salford.ac.uk) (146.87.255.76) by pan.salford.ac.uk with SMTP; 11 Dec 2000 15:24:21 -0000 Received: (qmail 36285 invoked by uid 141); 11 Dec 2000 15:24:21 -0000 Received: from localhost (sendmail-bs@127.0.0.1) by localhost with SMTP; 11 Dec 2000 15:24:21 -0000 Date: Mon, 11 Dec 2000 15:24:21 +0000 (GMT) From: Mark Powell To: freebsd-stable@freebsd.org Subject: Different gcc optimisations cause IP packet CRC problems Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-stable@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG Hi, On a PIII 600E, compiling a week old 4.2S kernel with the following options: -O2 -fomit-frame-pointer -mpentium -march=pentium -pipe Cause the kernel to produce TCP CRC errors when talking to certain IP addresses. It generally seemed to get the 2nd octet of the CRC out by one i.e. 0xb9f7 became 0xbaf7 etc. I originally did this, because I was using this fastish machine to remake world for another P166 machine. I forgot to change it back and accidentally recompiled it's own kernel with the above settings. This problem was fixed by simply changing the gcc optimisation to the correct CPU type: -O2 -fomit-frame-pointer -mpentiumpro -march=pentiumpro -pipe However, shouldn't the PIII be backwards compatible with any Pentium code? Or are there some incorrect assumptions made in the CRC generation code? Cheers. BTW Where in the source is the CRC generated? Mark Powell - UNIX System Administrator - The University of Salford Academic Information Services, Clifford Whitworth Building, Salford University, Manchester, M5 4WT, UK. Tel: +44 161 295 5936 Fax: +44 161 295 5888 www.pgp.com for PGP key To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message