Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753743AbdCBOXd (ORCPT ); Thu, 2 Mar 2017 09:23:33 -0500 Received: from bes.se.axis.com ([195.60.68.10]:46738 "EHLO bes.se.axis.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753571AbdCBOWi (ORCPT ); Thu, 2 Mar 2017 09:22:38 -0500 Date: Thu, 2 Mar 2017 15:13:56 +0100 From: Rabin Vincent To: =?utf-8?B?UmFmYcWCIE1pxYJlY2tp?= Cc: Daniel Lezcano , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Srinivas Kandagatla , Maxime Coquelin , Patrice Chotard , tglx@linutronix.de, Hauke Mehrtens Subject: Re: DIfferent BogoMIPS value after bbaa06702719 ("clocksource/drivers/arm_global_timer: Register delay timer") Message-ID: <20170302141356.GC6763@axis.com> References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) X-TM-AS-GCONF: 00 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1131 Lines: 29 On Thu, Mar 02, 2017 at 02:36:23PM +0100, Rafał Miłecki wrote: > I just updated kernel on my SmartRG SR400ac (bcm4708-smartrg-sr400ac.dts) from > 4.4 to 4.9 and noticed that this part of the log: > [ 0.020820] Calibrating delay loop... 1594.16 BogoMIPS (lpj=7970816) > (...) > [ 0.190806] Brought up 2 CPUs > [ 0.200022] SMP: Total of 2 processors activated (3188.32 BogoMIPS). > > became: > [ 0.027082] Calibrating delay loop (skipped), value calculated using timer frequency.. 800.00 BogoMIPS (lpj=4000000) > (...) > [ 0.078858] Brought up 2 CPUs > [ 0.088254] SMP: Total of 2 processors activated (1600.00 BogoMIPS). > > This is caused by commit bbaa06702719 ("clocksource/drivers/arm_global_timer: > Register delay timer"). > > Is this something expected? Or should I be worried about this? I'm aware it's > just BogoMIPS, but I still prefer to ask :) Yes, it's expected. No, you shouldn't be worried. It's even explained on Wikipedia: https://en.wikipedia.org/wiki/BogoMips#Timer-based_delays You can run the udelay test (CONFIG_TEST_UDELAY) if you want to make sure that your delay loops are fine.