Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758204AbYFKU6n (ORCPT ); Wed, 11 Jun 2008 16:58:43 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752227AbYFKU6e (ORCPT ); Wed, 11 Jun 2008 16:58:34 -0400 Received: from casper.infradead.org ([85.118.1.10]:54499 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752488AbYFKU6d (ORCPT ); Wed, 11 Jun 2008 16:58:33 -0400 Date: Wed, 11 Jun 2008 13:58:28 -0700 From: Arjan van de Ven To: markh@compro.net Cc: "linux-os (Dick Johnson)" , Jan Engelhardt , "Kok, Auke" , "solsTiCe d'Hiver" , linux-kernel@vger.kernel.org Subject: Re: PROBLEM: no cpu MHz in /proc/cpuinfo on 2.6.25.4-rt6 Message-ID: <20080611135828.29f6a7d7@infradead.org> In-Reply-To: <48503792.50003@compro.net> References: <200806102152.23286.solstice.dhiver@gmail.com> <20080610131314.5f7069e6@infradead.org> <484EE71A.40002@intel.com> <20080611063639.5e1eea5b@infradead.org> <20080611065816.6cff290d@infradead.org> <20080611083644.32afc823@infradead.org> <4850046C.4070602@compro.net> <20080611104446.3b0ce2d9@infradead.org> <48501159.4050908@compro.net> <48503792.50003@compro.net> Organization: Intel X-Mailer: Claws Mail 3.3.1 (GTK+ 2.12.10; i386-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 973 Lines: 28 On Wed, 11 Jun 2008 16:37:38 -0400 Mark Hounschell wrote: > > Mark > > > > Ok, what would one use besides the tsc to take a fast high-res time > stamp in a kernel module that could also be used in user land (same > time source) to for instance calculate the the time between an event > in the kernel to an event in user land? > > do_gettimeofday / gettimeofday are not really acceptable. btw you also changed the problem from "what is the cpu frequency" to "how usable is rdtsc for time". My entire point was that these weren't related... -- If you want to reach me at my work email, use arjan@linux.intel.com For development, discussion and tips for power savings, visit http://www.lesswatts.org -- 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/