From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gra-lx1.iram.es (gra-lx1.iram.es [150.214.224.41]) by ozlabs.org (Postfix) with ESMTP id EE16EDDE11 for ; Thu, 27 Nov 2008 04:05:47 +1100 (EST) Date: Wed, 26 Nov 2008 18:05:36 +0100 From: Gabriel Paubert To: Norbert van Bolhuis Subject: Re: too few bogoMips on MPC8313E-RDB ? Message-ID: <20081126170536.GA16864@iram.es> References: <492D1CA5.2090007@aimvalley.nl> <20081126102042.GA11397@mail.gnudd.com> <492D5B38.3080709@aimvalley.nl> <492D7219.8040501@mikroswiat.pl> <492D74C3.9060205@aimvalley.nl> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <492D74C3.9060205@aimvalley.nl> Cc: linuxppc-dev@ozlabs.org, linuxppc-embedded@ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Wed, Nov 26, 2008 at 05:09:39PM +0100, Norbert van Bolhuis wrote: > > ok, so it depends on the decrementer frequency > (which is 41666666 on my system). > > Btw. the main oscillator on my board is not 83.3 mhz, > it's 66 mhz as well. 66MHz is the crystal frequency, but then clock generators use PLL to generate about anything from it. Actually people use the abomination called DFS (frequency spreading) to comply with requirements on radiated energy; that's a bad joke, it does not actually reduce radiated energy, but spreads it over wider bandwidth which makes it much harder to detect with standard test equipement. > Hmmm. so by using the decrementer for the clock tick/irqs > (which perfectly makes sense) the bogoMIPS value is > nonsense now. That's a pity, but at least now I know/understand. > As far as I know, there are other architecture on which it is as bogus. Besides that it has the advantage of being really constant even when CPU frequency changes. Regards, Gabriel