From owner-freebsd-stable Sat Jul 27 22:19:48 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 6A61637B400 for ; Sat, 27 Jul 2002 22:19:46 -0700 (PDT) Received: from malasada.lava.net (malasada.lava.net [64.65.64.17]) by mx1.FreeBSD.org (Postfix) with ESMTP id 12C2943E67 for ; Sat, 27 Jul 2002 22:19:46 -0700 (PDT) (envelope-from cliftonr@lava.net) Received: from localhost (2141 bytes) by malasada.lava.net; Sat, 27 Jul 2002 19:19:45 -1000 (HST) via sendmail [stdio] id for Date: Sat, 27 Jul 2002 19:19:45 -1000 From: Clifton Royston To: freebsd-stable@FreeBSD.org Subject: Is use of -O2 still deprecated for buildworld in -stable? Message-ID: <20020727191945.A10231@lava.net> Mail-Followup-To: freebsd-stable@FreeBSD.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5.1i 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 I had a vigorous discussion about this with a colleague on Friday (yesterday.) We're trying to agree on the proper set of options to use in /etc/make.conf for doing "buildworld" and/or "buildkernel" i386 servers (Pentium 3.) These machines will be running production services for our customers, so they need to be high-reliability; we're running 4.5-release and 4.6-release CVSuped to those tags, not trying to track -stable. My colleague is insistent that because -O2 in gcc will generally produce much better code, we should be using it if it's at all possible and safe. He also was frankly disbelieving that there could be serious bugs in the optimization at the -O2 level because gcc is used so extensively in the Linux world, almost always with -O2. 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. In this case, we simply shouldn't be using it on production servers. I'm using it on my home machines (-O2 for world, -O for kernel) but they has altogether different needs for reliability. Am I correct in this, or are the warnings about -O2 in make.conf obsolete, or are they only applicable to non-i386 architectures, or to the kernel, or to -current? Can someone straighten me out here? -- Clifton -- Clifton Royston -- LavaNet Systems Architect -- cliftonr@lava.net "What do we need to make our world come alive? What does it take to make us sing? While we're waiting for the next one to arrive..." - Sisters of Mercy To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message