From mboxrd@z Thu Jan 1 00:00:00 1970 From: Frank Agius Subject: Re: AM335x mpurate + bogomips Date: Fri, 22 Feb 2013 11:43:25 -0500 Message-ID: <5127A02D.8040200@yahoo.com> References: <51264CFF.8050200@mimc.co.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from plane.gmane.org ([80.91.229.3]:43363 "EHLO plane.gmane.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757880Ab3BVQng (ORCPT ); Fri, 22 Feb 2013 11:43:36 -0500 Received: from list by plane.gmane.org with local (Exim 4.69) (envelope-from ) id 1U8vj1-0004c3-5e for linux-omap@vger.kernel.org; Fri, 22 Feb 2013 17:43:55 +0100 Received: from 99-178-168-231.lightspeed.rlghnc.sbcglobal.net ([99.178.168.231]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Fri, 22 Feb 2013 17:43:55 +0100 Received: from ftagius by 99-178-168-231.lightspeed.rlghnc.sbcglobal.net with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Fri, 22 Feb 2013 17:43:55 +0100 In-Reply-To: <51264CFF.8050200@mimc.co.uk> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org Cc: "linux-omap@vger.kernel.org" On 2/21/2013 11:36 AM, Mark Jackson wrote: > Before I dig any deeper, can anyone tell me if the bootarg "mpurate" is meant to > be supported for AM335x SoCs ? > > I've tried it on our custom board using 3v8, but no joy. > > The boot log shows:- > > [ 0.000000] Booting Linux on physical CPU 0x0 > [ 0.000000] Linux version 3.8.0-03059-g621553c-dirty (mpfj@mpfj-nanobone) (gcc version 4.5.4 (Buildroot 2012.11) ) #113 SMP Thu Feb 21 16:29:48 GMT 2013 > [ 0.000000] CPU: ARMv7 Processor [413fc082] revision 2 (ARMv7), cr=10c53c7d > [ 0.000000] CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache > [ 0.000000] Machine: Generic AM33XX (Flattened Device Tree), model: Newflow NanoBone > [ 0.000000] Memory policy: ECC disabled, Data cache writeback > [ 0.000000] CPU: All CPU(s) started in SVC mode. > [ 0.000000] AM335X ES1.0 (neon ) > ... > [ 0.000000] Kernel command line: console=ttyO0,115200n8 mpurate=720 root=/dev/mmcblk0p2 ro rootfstype=ext2 rootwait > ... > [ 0.001119] Calibrating delay loop... 364.48 BogoMIPS (lpj=1425408) > > I have seen other boot logs outputs [1] from other people where they are getting nearly double that. > I have also observed a drop in the reported BogoMIPS value when using the latest kernel. Previously (with a 3.5 kernel) the BogoMIPS value was approximately equal to the CPU frequency. I finally found the reason for the BogoMIPS change: http://www.spinics.net/lists/arm-kernel/msg221672.html It looks like BogoMIPS reporting changed because of the delay routine patch introduced in 3.6. So the change in BogoMIPS is real, but should not be a concern. frank agius