Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756532AbXLKRES (ORCPT ); Tue, 11 Dec 2007 12:04:18 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752878AbXLKRD7 (ORCPT ); Tue, 11 Dec 2007 12:03:59 -0500 Received: from mx3.mail.elte.hu ([157.181.1.138]:58335 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751229AbXLKRD6 (ORCPT ); Tue, 11 Dec 2007 12:03:58 -0500 Date: Tue, 11 Dec 2007 18:03:34 +0100 From: Ingo Molnar To: Arjan van de Ven Cc: dor.laor@qumranet.com, tglx@linutronix.de, Linux Kernel Mailing List , kvm-devel Subject: Re: Performance overhead of get_cycles_sync Message-ID: <20071211170334.GA30144@elte.hu> References: <475E8C8B.7070308@qumranet.com> <20071211133738.GA8150@elte.hu> <475E9A92.4030001@qumranet.com> <20071211142717.GA15903@elte.hu> <20071211083513.56c2a385@laptopd505.fenrus.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20071211083513.56c2a385@laptopd505.fenrus.org> User-Agent: Mutt/1.5.17 (2007-11-01) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 846 Lines: 25 * Arjan van de Ven wrote: > > * Dor Laor wrote: > > > > The patch below should resolve this - could you please test and Ack > > it? But this CPUID was present in v2.6.23 too, so why did it only > > show up in 2.6.24-rc for you? > > isn't this probably wrong since this code is also used in the vsyscall > code.. the TSC clocksource (and hence the vsyscall code) is turned off on systems that fail the TOD/CLOCK portion of this test: http://people.redhat.com/mingo/time-warp-test/time-warp-test.c i.e. on the majority of systems in place. Ingo -- 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/