From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <3926CD15.441C87AB@embeddededge.com> Date: Sat, 20 May 2000 13:36:21 -0400 From: Dan Malek MIME-Version: 1.0 To: Seungdong Lee CC: Dan Malek , linuxppc-embedded@lists.linuxppc.org Subject: Re: 8240 BogoMIPS References: <39263EA0.69C60AA9@da-san.com> Content-Type: text/plain; charset=us-ascii Sender: owner-linuxppc-embedded@lists.linuxppc.org List-Id: Seungdong Lee wrote: > > Hi Dan, I have successfully ported Linux to my customized 8240 board. Cool! Good job. What version of software are you using? Did you make any changes or want your board part of the kernel tree? > Linux runs fine, but I found that the performance is not as good as my > expectation. Is this just based on the BogoMIPS number, or do you have some benchmarks for comparison? > BogoMIPS value of my board is currently 131.89. I have not booted my 8240 for a while, and I don't remember the number. I have another 8240 showing up soon, so I will be back on that before long and will pay attention to this. For some reason, I do remember that with caches disabled this number is _really_ small, like 13 or 18 or something. I don't believe any absolute number here. I just use it for a quick reference when I am testing various cache combinations to indicate that I am booting the kernel I wish to be using. If this doesn't seem correct, ensure the processor is really running at the clock rate you expect. Verify external clocks, PLLs and the like. Also, make sure the timers used to determine this value are properly programmed. One test I always perform is to run 'sleep 10' at the shell prompt, and time it with my watch. It should be really close to 10 seconds, 9 or 11 on my watch are not close :-). > Both I/D-cache are enabled. So, theoretical BogoMIPS should be around > 400. I wouldn't use BogoMIPS for any kind of benchmark. There have been plenty of discussions on mailing lists (including linuxppc lists) to indicate this abosolute number doesn't mean much. I have many PowerPC systems running Linux, from 8xx embedded though 7400/G4 systems. I certainly can't predict what this number "should" be. Verify clocks and timers are working and run some real benchmarks. -- Dan ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/