From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751359AbWJEVHF (ORCPT ); Thu, 5 Oct 2006 17:07:05 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751360AbWJEVHF (ORCPT ); Thu, 5 Oct 2006 17:07:05 -0400 Received: from www.osadl.org ([213.239.205.134]:21389 "EHLO mail.tglx.de") by vger.kernel.org with ESMTP id S1751359AbWJEVHD (ORCPT ); Thu, 5 Oct 2006 17:07:03 -0400 Subject: Re: [patch 00/22] high resolution timers / dynamic ticks - V3 From: Thomas Gleixner Reply-To: tglx@linutronix.de To: Andi Kleen Cc: Ingo Molnar , LKML , John Stultz , Valdis Kletnieks , Arjan van de Ven , Dave Jones , David Woodhouse , Jim Gettys , Roman Zippel , akpm@osdl.org In-Reply-To: References: <20061004172217.092570000@cruncher.tec.linutronix.de> <20061005011608.b69e3461.akpm@osdl.org> <20061005081725.GA28877@elte.hu> Content-Type: text/plain Date: Thu, 05 Oct 2006 23:11:56 +0200 Message-Id: <1160082716.9060.105.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.6.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2006-10-05 at 22:57 +0200, Andi Kleen wrote: > > ah, that's still the VAIO, right? Do you get a 'slow' LOC count on > > /proc/interrupts even on a stock kernel? If yes then that's a > > fundamentally sick local APIC timer interrupt. Stock kernel should show > > sickness too, if for example you boot an SMP kernel on it - can you > > confirm that? (the UP-IOAPIC only relies for profiling on the lapic > > timer, so there the only sickness you should see on the stock kernel is > > a non-working readprofile) > > When I was hacking on my old noidletick patch I ran into this > problem on several machines too. > > But usually the problem wasn't that it was too slow, but that > it completely stopped in C2 or deeper. I don't think there > is a way to work around that except for not using C2 or deeper > (not an option) or using a different timer source. > > If that is true then hitting space lots of time will make it > go faster. If that's the case we can even autodetect it and stay with PIT and ignore lapic all the way. tglx