From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755704AbXIHXF0 (ORCPT ); Sat, 8 Sep 2007 19:05:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754835AbXIHXFO (ORCPT ); Sat, 8 Sep 2007 19:05:14 -0400 Received: from smtp-vbr12.xs4all.nl ([194.109.24.32]:4302 "EHLO smtp-vbr12.xs4all.nl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752317AbXIHXFM (ORCPT ); Sat, 8 Sep 2007 19:05:12 -0400 Message-ID: <46E32A5D.7080009@xs4all.nl> Date: Sun, 09 Sep 2007 01:03:57 +0200 From: Bauke Jan Douma Reply-To: bjdouma@xs4all.nl Organization: a training zoo User-Agent: Thunderbird 2.0.0.6 (X11/20070728) MIME-Version: 1.0 To: Bill Davidsen CC: linux-kernel@vger.kernel.org Subject: Re: bogomips discrepancy on Intel Core2 Quad CPU References: <46DBC092.8030209@xs4all.nl> <46DC1E9B.3030108@tmr.com> In-Reply-To: <46DC1E9B.3030108@tmr.com> Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Bill Davidsen wrote on 03-09-07 16:47: > Bauke Jan Douma wrote: >> $> uname -a >> Linux skyscraper 2.6.22.5 #7 SMP PREEMPT Sun Sep 2 12:12:25 CEST 2007 >> i686 GNU/Linux >> >> $> cat /proc/cpuinfo | grep bogomips >> bogomips : 4813.46 >> bogomips : 4810.91 >> bogomips : 4810.91 >> bogomips : 10583.94 >> >> The latter seems way off base. >> Prod me for more info. >> > I see this occasionally on a dual, speedstep (or similar) finds a way to > throttle down the cores under light load. I suspect that if you load the > system: > > for n in 1 2 3 4; do > nice -19 bash -c 'while true; do a=$RANDOM; done' & > done > > Then you should see your bogomips rise on all cores. Sorry for now getting back on this sooner. Other matters forced it to the backburner. I don't have Speedstep enabled on this machine's kernel (as a matter of fact, the entire cpufreq Kconfig subtree is unchecked). Needless to say running your bash script doesn't change the values in any way. I'd say the 4800-something bogomips value is the correct one (for a 2.4GHz CPU -- at least that's what I recall on single-CPU machines, mostly bogomips being approx. twice the rated CPU speed), and the 10000-something is the one off base. Btw., the 10000 can be something like 12000-odd after a machine reboot, and readout on a different CPU. The rest are all ca. 4810. Odd indeed. bjd