From owner-freebsd-current@FreeBSD.ORG Fri May 7 13:08:33 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 08AC016A4CE; Fri, 7 May 2004 13:08:33 -0700 (PDT) Received: from carver.gumbysoft.com (carver.gumbysoft.com [66.220.23.50]) by mx1.FreeBSD.org (Postfix) with ESMTP id C826043D58; Fri, 7 May 2004 13:08:32 -0700 (PDT) (envelope-from dwhite@gumbysoft.com) Received: by carver.gumbysoft.com (Postfix, from userid 1000) id BAA8A72DBF; Fri, 7 May 2004 13:08:32 -0700 (PDT) Received: from localhost (localhost [127.0.0.1]) by carver.gumbysoft.com (Postfix) with ESMTP id B56F272DB5; Fri, 7 May 2004 13:08:32 -0700 (PDT) Date: Fri, 7 May 2004 13:08:32 -0700 (PDT) From: Doug White To: David O'Brien In-Reply-To: <20040505054723.GB30514@dragon.nuxi.com> Message-ID: <20040507130607.Q42861@carver.gumbysoft.com> References: <20040430135155.C67990@carver.gumbysoft.com> <20040505054723.GB30514@dragon.nuxi.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII 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 20:08:33 -0000 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. -- Doug White | FreeBSD: The Power to Serve dwhite@gumbysoft.com | www.FreeBSD.org