From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761067Ab2DKUJi (ORCPT ); Wed, 11 Apr 2012 16:09:38 -0400 Received: from mail-yx0-f174.google.com ([209.85.213.174]:50641 "EHLO mail-yx0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753671Ab2DKUJh (ORCPT ); Wed, 11 Apr 2012 16:09:37 -0400 Subject: Re: [PATCH] clocksource: Load the ACPI PM clocksource asynchronously Date: Wed, 11 Apr 2012 20:04:45 -0000 From: Michael Witten To: Arjan van de Ven Cc: Arjan van de Ven , John Stultz , Thomas Gleixner , Len Brown , linux-kernel@vger.kernel.org Message-ID: <041683e0088341c2b6d78e97f05948eb-mfwitten@gmail.com> In-Reply-To: References: <20120130205120.652aa64f@infradead.org> <717f591b21b34ebea5793c6206b8a2b8-mfwitten@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 8 Apr 2012 19:20:22 -0700, Arjan van de Ven wrote: >> to which I bisected as the culprit for very strange load balance >> behavior on my machine. >> >> With this patch in place, my CPU is constantly being pegged at 100% >> (and my CPU monitor sometimes registers NaN%), regardless of the >> active governor and under conditions when my computer would normally >> be idling quite placidly. >> >> Reverting this commit does indeed remove the problem from previously >> problematic builds. >> >> > any chance of a dmesg? (or even better, a diff of the dmesg from > abefore and fter) Doh! I should have thought of that. The dmesg output for a kernel built from your patch's commit yields this interesting line: PM-Timer running at invalid rate: 113% of normal - aborting. That certainly sounds unsavory! Here is some other, probably uninteresting context: --- good-dmesg.txt +++ bad-dmesg.txt [...] Initializing cgroup subsys cpu -Linux version 3.3.0-rc1-good-12d6d41276def096cb3f7dc36f438db9ed6a0a8d+ [...] +Linux version 3.3.0-rc1-bad-b519508298e0292e1771eecf14aaf67755adc39d+ [...] [...] Fast TSC calibration using PIT -Detected 798.093 MHz processor. +Detected 798.071 MHz processor. -Calibrating delay loop (skipped), value calculated using timer frequency.. 1596.18 BogoMIPS (lpj=798093) +Calibrating delay loop (skipped), value calculated using timer frequency.. 1596.14 BogoMIPS (lpj=798071) pid_max: default: 32768 minimum: 301 Mount-cache hash table entries: 512 Initializing cgroup subsys cpuacct [...] system 00:0c: Plug and Play ACPI device, IDs PNP0c01 (active) pnp: PnP ACPI: found 13 devices ACPI: ACPI bus type pnp unregistered -Switching to clocksource acpi_pm [...] +PM-Timer running at invalid rate: 113% of normal - aborting. Sincerely, Michael Witten P.S. I'm terribly sorry for the delayed reply; Gmail somehow managed to throw away this thread entirely (actually, I probably threw it away, but I'm content to blame my tools; after all, they can't deny it!).