From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752539AbYI1K7s (ORCPT ); Sun, 28 Sep 2008 06:59:48 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751729AbYI1K7j (ORCPT ); Sun, 28 Sep 2008 06:59:39 -0400 Received: from www.tglx.de ([62.245.132.106]:37550 "EHLO www.tglx.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751073AbYI1K7i (ORCPT ); Sun, 28 Sep 2008 06:59:38 -0400 Date: Sun, 28 Sep 2008 12:58:34 +0200 (CEST) From: Thomas Gleixner To: Jason Vas Dias cc: "Rafael J. Wysocki" , Andrew Morton , Linux Kernel Mailing List , Kernel Testers List , Len Brown Subject: Re: [Bug #11516] severe performance degradation on x86_64 going from 2.6.26-rc9 -> 2.6.27-rc5 In-Reply-To: <200809280138.57672.jason.vas.dias@gmail.com> Message-ID: References: <200809230549.28544.jason.vas.dias@gmail.com> <200809280138.57672.jason.vas.dias@gmail.com> User-Agent: Alpine 1.10 (LFD 962 2008-03-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 28 Sep 2008, Jason Vas Dias wrote: > The problem is not "slow booting" - indeed, as noted in the bug, boot time up to the point > where user space should start is very similar to the non-problematic 2.6.26 kernels. > > The USB problem is that @ 10 messages per second are emitted to the log: > Sep 28 00:41:51 localhost kernel: [ 11.985257] hub 3-0:1.0: state 7 ports 2 chg 0000 evt 0002 > Sep 28 00:41:51 localhost kernel: [ 12.789240] hub 1-0:1.0: state 7 ports 2 chg 0000 evt 0004 > Sep 28 00:41:51 localhost kernel: [ 12.937169] hub 4-0:1.0: state 7 ports 2 chg 0000 evt 0000 > Sep 28 00:41:51 localhost kernel: [ 12.937188] hub 3-0:1.0: state 7 ports 2 chg 0000 evt 0002 > Sep 28 00:41:51 localhost kernel: [ 13.041167] hub 5-0:1.0: state 7 ports 2 chg 0000 evt 0000 > Sep 28 00:41:51 localhost kernel: [ 13.041186] hub 6-0:1.0: state 7 ports 10 chg 0000 evt 0000 > Sep 28 00:41:51 localhost kernel: [ 13.453734] hub 6-0:1.0: state 7 ports 10 chg 0000 evt 0020 > Sep 28 00:41:51 localhost kernel: [ 13.453748] hub 1-0:1.0: state 7 ports 2 chg 0000 evt 0004 > Sep 28 00:41:51 localhost kernel: [ 13.846512] hub 3-0:1.0: state 7 ports 2 chg 0000 evt 0002 > Sep 28 00:41:51 localhost kernel: [ 14.220994] hub 3-0:1.0: state 7 ports 2 chg 0000 evt 0002 > > Why should USB be emitting state change messages when no state has changed ? That's a separate question. > I think this is because the core PM-timer (clocksource is acpi-pm) is kaput , > and every driver that depends on high-resolution timers gets confused . No, if the pmtimer would be defect your machine would not even reach user space. I analysed the proc/acpi data of .25 and .27 and the machine is set to throttling state T7 (12%) which would explain that behaviour halfways. Can you please verify if that state is always T7 on your machine with .27 ? Also please add "acpi.debug_level=0x11" to the kernel command line so we can get some more information out of the ACPI code. > Displaying text on the terminal is @ 140 times slower under 2.6.27 > kernels than under 2.6.26 kernels . Downloads over the network take > @ 1000 times longer under 2.6.27 than under 2.6.26. Disk I/O is @ > 100 times slower. That's indeed insane. > There are numerous log messages about "interrupt during system call" > (EINTR) from user-space processes. Separate problem as well. Please let us concentrate on the throttling aspect and not mix USB/EINTR stuff into it for now. Thanks, tglx