From owner-freebsd-stable Mon Jul 29 9: 5:49 2002 Delivered-To: freebsd-stable@freebsd.org Received: from mx1.FreeBSD.org (mx1.FreeBSD.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 9B30337B401 for ; Mon, 29 Jul 2002 09:05:45 -0700 (PDT) Received: from wall.polstra.com (wall-gw.polstra.com [206.213.73.130]) by mx1.FreeBSD.org (Postfix) with ESMTP id 32F6543E5E for ; Mon, 29 Jul 2002 09:05:44 -0700 (PDT) (envelope-from jdp@polstra.com) Received: from vashon.polstra.com (vashon.polstra.com [206.213.73.13]) by wall.polstra.com (8.11.3/8.11.3) with ESMTP id g6TG5ca11773; Mon, 29 Jul 2002 09:05:38 -0700 (PDT) (envelope-from jdp@vashon.polstra.com) Received: (from jdp@localhost) by vashon.polstra.com (8.12.4/8.12.4/Submit) id g6TG5bK4042448; Mon, 29 Jul 2002 09:05:37 -0700 (PDT) (envelope-from jdp) Date: Mon, 29 Jul 2002 09:05:37 -0700 (PDT) Message-Id: <200207291605.g6TG5bK4042448@vashon.polstra.com> To: stable@freebsd.org From: John Polstra Cc: gnb@itga.com.au Subject: Re: Is use of -O2 still deprecated for buildworld in -stable? In-Reply-To: <200207290447.OAA22147@lightning.itga.com.au> References: <200207290447.OAA22147@lightning.itga.com.au> Organization: Polstra & Co., Seattle, WA Sender: owner-freebsd-stable@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG In article <200207290447.OAA22147@lightning.itga.com.au>, Gregory Bond wrote: > > My understanding is that whether or not -O2 *should* produce exactly > > equivalent code to -O, there are recurrent reports of people having > > trouble doing a buildworld with -O2 in -stable or in 4.x release > > trains, where their problems go away when they revert back to -O. > > The TCP checksum code seems to be the most common culprit - compiling with -O2 > seems to create checksum routines that fail in certain corner cases, meaning > some hosts or some data patterns cause TCP sessions to freeze. > > [I've not seen it myself, but it has been reported here a couple of times.] I fixed the checksum code in both -current and -stable a few weeks ago. FWIW, a kernel I built with "-O2 -fomit-frame-pointer" for a network-intensive configuration worked fine. For my application (generating and servicing zillions of web requests using special netgraph nodes I made) these options increased performance by about 9% compared to the same kernel built with "-O". John -- John Polstra John D. Polstra & Co., Inc. Seattle, Washington USA "Disappointment is a good sign of basic intelligence." -- Chögyam Trungpa To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message