From owner-freebsd-current@FreeBSD.ORG Fri May 7 13:32:09 2004 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id D615316A4CE; Fri, 7 May 2004 13:32:09 -0700 (PDT) Received: from pooker.samsco.org (pooker.samsco.org [168.103.85.57]) by mx1.FreeBSD.org (Postfix) with ESMTP id 5406F43D41; Fri, 7 May 2004 13:32:09 -0700 (PDT) (envelope-from scottl@freebsd.org) Received: from freebsd.org (g4.samsco.home [192.168.0.12]) by pooker.samsco.org (8.12.10/8.12.10) with ESMTP id i47KaXu6040593; Fri, 7 May 2004 14:36:33 -0600 (MDT) (envelope-from scottl@freebsd.org) Message-ID: <409BF210.8030307@freebsd.org> Date: Fri, 07 May 2004 14:31:12 -0600 From: Scott Long User-Agent: Mozilla/5.0 (Macintosh; U; PPC Mac OS X Mach-O; en-US; rv:1.7a) Gecko/20040214 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Doug White References: <20040430135155.C67990@carver.gumbysoft.com> <20040505054723.GB30514@dragon.nuxi.com> <20040507130607.Q42861@carver.gumbysoft.com> In-Reply-To: <20040507130607.Q42861@carver.gumbysoft.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Status: No, hits=0.0 required=3.8 tests=none autolearn=no version=2.63 X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on pooker.samsco.org cc: current@freebsd.org Subject: Re: src/sys/vm/vm_init.c v1.43 hangs amd64 X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 07 May 2004 20:32:09 -0000 Doug White wrote: > On Tue, 4 May 2004, David O'Brien wrote: > > >>On Sat, May 01, 2004 at 08:42:46AM -0700, Doug White wrote: >> >>>2. Changing COPTFLAGS to '-O -frename-registers -pipe' from the default >>>'-O2 -frename-registers -pipe' stops the crash. So it may be an >>>O2-specific optimization bug. >> >>... >> >>>So in the end, at -O2, (nswbuf*MAXPHYS) != nswbuf*MAXPHYS. Creepy, eh? >>>I'll see if I can come up with a standalone test case to submit to the gcc >>>folks. >> >>Thanks! >>This is the first report of an -O2 problem, and I'm very happy you're >>willing to try to narrow this down so we don't have to return to -O[1]. > > > I caught kan's attention with this last night on irc, and he's going to > try to isolate the bad code generation. We could really use a standalone > case to test with & submit, but a naieve test doesn't come up with any > differences. > > In order to keep my amd64 stable I'm having to leave COPTFLAGS set, so if > someone commits a fix to gcc or imports a new version, try to get my > attention so I can test it with -O2 again. > > Also if we get into the 5.3 release timeframe we'll have to make a call to > ship with a -O2 compiled kernel or not. > Are you proposing dropping -O2 for 5.3 because you are afraid that there are other, not-yet-detected broken cases? I thought that we found a source code work-around that forced gcc to generate the correct assembly with -O2. Maybe that should be committed for the time being? Scott