SSSSlllloooowwww MPC8240

Jerry Van Baren vanbaren_gerald at
Tue Jul 10 11:37:57 EST 2001

Is caching enabled (both instruction and data)?  It sounds a lot like
you are running without the benefit of caches.  Another possibility is
that you are being swamped with interrupts, but I vaguely recall that
should not be a problem for the start up bogomips calculation.


At 06:57 PM 7/9/01 -0400, anj at wrote:

>Can anybody suggest why I'm seeing the following:
>Under Hard Hat Linux 2.0 (2.4.2 kernel) on my MVME2100 board (MPC8240 CPU
>running at 200MHz), Linux startup reports a BogoMIPS rating of 9.59.  I've
>just built and run the exact same calibration code under vxWorks, and here
>I get a rating of 133.73 BogoMIPS, which seems much more likely to be
>correct.  Linux does seem rather sluggish at running things, so I don't
>think it's problem with the calibration.  Any ideas what could be going on
>behind the scenes to slow Linux down, and how I might track it down?
>I wonder whether it's related to that openpic interrupt stuff in the other
>- Andrew
>The world is such a cheerful place when viewed from upside-down
>It makes a rise of every fall, a smile of every frown

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