From owner-freebsd-current@FreeBSD.ORG Mon May 29 08:57:57 2006 Return-Path: X-Original-To: freebsd-current@freebsd.org 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 1422316A602; Mon, 29 May 2006 08:57:57 +0000 (UTC) (envelope-from yar@comp.chem.msu.su) Received: from comp.chem.msu.su (comp.chem.msu.su [158.250.32.97]) by mx1.FreeBSD.org (Postfix) with ESMTP id 8264E43D46; Mon, 29 May 2006 08:57:53 +0000 (GMT) (envelope-from yar@comp.chem.msu.su) Received: from comp.chem.msu.su (localhost [127.0.0.1]) by comp.chem.msu.su (8.13.4/8.13.3) with ESMTP id k4T8vOOO099169; Mon, 29 May 2006 12:57:24 +0400 (MSD) (envelope-from yar@comp.chem.msu.su) Received: (from yar@localhost) by comp.chem.msu.su (8.13.4/8.13.3/Submit) id k4T8vO2Q099168; Mon, 29 May 2006 12:57:24 +0400 (MSD) (envelope-from yar) Date: Mon, 29 May 2006 12:57:23 +0400 From: Yar Tikhiy To: Kevin Oberman Message-ID: <20060529085723.GA98288@comp.chem.msu.su> References: <20060528142039.GA80613@comp.chem.msu.su> <20060528221154.7351845043@ptavv.es.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20060528221154.7351845043@ptavv.es.net> User-Agent: Mutt/1.5.9i Cc: njl@freebsd.org, freebsd-current@freebsd.org Subject: Re: Freeze due to performance_cx_lowest=LOW X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 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: Mon, 29 May 2006 08:57:57 -0000 On Sun, May 28, 2006 at 03:11:54PM -0700, Kevin Oberman wrote: > > > > A while ago I installed CURRENT on my new home PC and noticed that > > the system would hang hard at the boot time soon after setting > > cx_lowest to C3 according to the LOW setting in /etc/defaults/rc.conf. > > The last message on the console was each time: Mounting NFS file > > systems:. Setting performance_cx_lowest to HIGH made the problem > > go away. > > > > Now I've just tried again to return performance_cx_lowest to its > > modern default setting in a fresh CURRENT and found that the bug > > is still there. Is it due to my ACPI HW being broken? I'll be > > glad to show relevant debug output from my ACPI if told how to get > > it. Thanks. > > This problem has been discussed over on ACPI. It's a problem with the > local APIC timer which does not run in C3 or lower. Nate is looking at a > solution for the problem. > > See his message on acpi@ on Sun, 07 May 2006 15:28:29 -0700. It must be http://lists.freebsd.org/pipermail/freebsd-acpi/2006-May/002742.html Right? > The fixes are to either not use C3 (or C4 if it's available) or to > disable APIC. > > For those who are not reading closely, DO NOT confuse APIC with ACPI! > They only look similar. > > If the system is UP, there is no really no need for APIC. Thanks for pointing me out. FWIW, I tried different work-arounds in my system and got the following results. Set performance_cx_lowest to as high as C2 in rc.conf -- works. Add hint.apic.0.disabled="1" to device.hints -- doesn't work, the system still hangs. I can't see apic mentioned in the dmesg output irrespective of the setting, but it must be there, given the results of the next test. Remove device apic from the kernel completely -- the system won't halt, but it may suffer data corruption: once syslogd complained about wrong syntax in its config, which I hadn't touched of course. (Syslogd starts soon after cx_lowest was set to C3.) At last "cpu0: too many short sleeps, backing off to C2" appears on the console, and hw.acpi.cpu.cx_lowest goes up to C2 indeed. Of course, I shouldn't rule out bugs in my hardware, it is quite old, a plain vanilla AMD Athlon (Thunderbird) in an Epox EP-8K3AE motherboard. Nevertheless, given the problems other people have had, it might be too early to have performance_cx_lowest=LOW as the _default_ setting. ACPI is a rather special area with some skilled developers working in it, and encouraging everyone else in this way to fix it makes little sense IMHO. -- Yar