From owner-freebsd-stable@FreeBSD.ORG Wed Sep 9 03:42:56 2009 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id C1B541065670 for ; Wed, 9 Sep 2009 03:42:56 +0000 (UTC) (envelope-from rnoland@FreeBSD.org) Received: from gizmo.2hip.net (gizmo.2hip.net [64.74.207.195]) by mx1.freebsd.org (Postfix) with ESMTP id 89E0B8FC08 for ; Wed, 9 Sep 2009 03:42:55 +0000 (UTC) Received: from [192.168.1.4] (adsl-146-128-114.bna.bellsouth.net [70.146.128.114]) (authenticated bits=0) by gizmo.2hip.net (8.14.3/8.14.3) with ESMTP id n893goIn048289 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Tue, 8 Sep 2009 23:42:53 -0400 (EDT) (envelope-from rnoland@FreeBSD.org) From: Robert Noland To: "Daniel O'Connor" In-Reply-To: <200909091020.51049.doconnor@gsoft.com.au> References: <200909082209.37454.doconnor@gsoft.com.au> <20090909030624.Y89278@sola.nimnet.asn.au> <200909091020.51049.doconnor@gsoft.com.au> Content-Type: text/plain Organization: FreeBSD Date: Tue, 08 Sep 2009 22:42:44 -0500 Message-Id: <1252467764.85394.2903.camel@balrog.2hip.net> Mime-Version: 1.0 X-Mailer: Evolution 2.26.3 FreeBSD GNOME Team Port Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-1.8 required=5.0 tests=AWL,BAYES_00,RCVD_IN_PBL, RDNS_DYNAMIC,SPF_SOFTFAIL autolearn=no version=3.2.5 X-Spam-Checker-Version: SpamAssassin 3.2.5 (2008-06-10) on gizmo.2hip.net Cc: Henrik Friedrichsen , FreeBSD Stable , Ian Smith Subject: Re: Detecting CPU throttling on over temperature X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 09 Sep 2009 03:42:56 -0000 On Wed, 2009-09-09 at 10:20 +0930, Daniel O'Connor wrote: > On Wed, 9 Sep 2009, Ian Smith wrote: > > > > Does anyone know if it is possible to determine if this is the > > > > case? ie is there a way to be informed if throttling has > > > > occurred? > > > > Might be easier to hack powerd.c as an existing pretty lightweight > > way of monitoring CPU freq (to log or signal on detected freq lowered > > by throttling, say?) even if you don't need/want it to actually vary > > freq according to load, eg setting idle/busy shift factors to > > 'never/always'? > > Hmm, that could work. > > It seems odd to me that there is no direct way the BIOS can notify the > OS it's throttling the CPU though. Some BIOS can and do send an ACPI event when the proc gets hot. In my experience, this was not a good thing though. The BIOS that I remember dealing with this on would continuously send the alarms, so while TCC would kick in and throttle the CPU, the event processing kept it at 100% utilization until it was powered off to cool. I have also been able to determine that TCC had kicked in by looking at the cpu frequency via sysctl and comparing that to the max frequency reported for the proc. If the BIOS sent the alarm, but throttled the rate it wouldn't have been so bad. Not that I had any active fan control on that box to do anything about it really, but TCC might have actually worked if it wasn't flooding the acpi event processor. robert. -- Robert Noland FreeBSD