Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1946428AbWKJLLw (ORCPT ); Fri, 10 Nov 2006 06:11:52 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1946446AbWKJLLw (ORCPT ); Fri, 10 Nov 2006 06:11:52 -0500 Received: from gprs189-60.eurotel.cz ([160.218.189.60]:28865 "EHLO amd.ucw.cz") by vger.kernel.org with ESMTP id S1946428AbWKJLLw (ORCPT ); Fri, 10 Nov 2006 06:11:52 -0500 Date: Fri, 10 Nov 2006 12:11:34 +0100 From: Pavel Machek To: Thomas Gleixner , vojtech@suse.cz, jbohac@suse.cz Cc: Andi Kleen , john stultz , Andrew Morton , LKML , Ingo Molnar , Len Brown , Arjan van de Ven , Roman Zippel Subject: Re: [patch 13/19] GTOD: Mark TSC unusable for highres timers Message-ID: <20061110111134.GA3291@elf.ucw.cz> References: <20061109233030.915859000@cruncher.tec.linutronix.de> <20061109233035.569684000@cruncher.tec.linutronix.de> <1163121045.836.69.camel@localhost> <200611100610.13957.ak@suse.de> <1163146206.8335.183.camel@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1163146206.8335.183.camel@localhost.localdomain> X-Warning: Reading this can be dangerous to your mental health. User-Agent: Mutt/1.5.11+cvs20060126 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1921 Lines: 54 Ahoj! Tahle debata (lkml) by se Vam mohla hodit... Pavel On Fri 2006-11-10 09:10:06, Thomas Gleixner wrote: > On Fri, 2006-11-10 at 06:10 +0100, Andi Kleen wrote: > > > > verify_tsc_freq_timer.function = verify_tsc_freq; > > > > verify_tsc_freq_timer.expires = > > > > > > > > > Hmmm. I wish this patch was unnecessary, but I don't see an easy > > > solution. > > > > Very sad. This will make a lot of people unhappy, even to the point > > where they might prefer disabling noidlehz over super slow gettimeofday. > > I assume you at least have a suitable command line option for that, right? > > Yes it is sad. And the sadest part is that AMD and Intel have been asked > to fix that more than 5 years ago. They did not get their brain straight > and now we are the dimwits. > > > Can we get a summary on which systems the TSC is considered unstable? > > Normally we assume if it's stable enough for gettimeofday it should > > be stable enough for longer delays too. > > TSC is simply a nightmare: > > - Frequency changes with CPU clock > - Unsynced across CPUs > - Stops in C3, which makes it completely unusable > > Once you take away periodic interrupts it is simply broken. AMD and > Intel can run in circels, it does not get better. > > tglx > > > > > - > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/