From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757196AbYIAUXS (ORCPT ); Mon, 1 Sep 2008 16:23:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751659AbYIAUXH (ORCPT ); Mon, 1 Sep 2008 16:23:07 -0400 Received: from mtiwmhc13.worldnet.att.net ([204.127.131.117]:59050 "EHLO mtiwmhc13.worldnet.att.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751544AbYIAUXG (ORCPT ); Mon, 1 Sep 2008 16:23:06 -0400 Message-ID: <48BC4F3A.9020608@lwfinger.net> Date: Mon, 01 Sep 2008 15:23:22 -0500 From: Larry Finger User-Agent: Thunderbird 2.0.0.12 (X11/20071114) MIME-Version: 1.0 To: Thomas Gleixner CC: LKML , "Rafael J. Wysocki" , Linus Torvalds , Alok Kataria , Michael Buesch Subject: Re: Regression in 2.6.27 caused by commit bfc0f59 References: <48BB2116.1060904@lwfinger.net> <48BC2A03.9000104@lwfinger.net> <48BC444D.5030601@lwfinger.net> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Thomas Gleixner wrote: > On Mon, 1 Sep 2008, Larry Finger wrote: >> The timed sleep is as accurate as I can measure. >> >> I put in some test prints. The value of pm2 is zero when the else branch of >> the "if (hpet)" is entered; however, pm1 is 15768471. When we reach the >> do_div(tsc2, tsc1) statement, tsc2 is zero, which I think means that the two >> calls to tsc_read_refs() are returning the same junk value. > > Ok, so the pmtimer is probably detected later as unusable and disabled. > Please check your logs for: > "PM-Timer had inconsistent results:" Booting 2.6.26, the dmesg output has a line that says: PM-Timer running at invalid rate: 200% of normal - aborting. Amazing that it should be exactly 200%. Why is the CPU running at half speed when the PM-Timer rate is measured? Larry