SSSSlllloooowwww MPC8240

SSSSlllloooowwww MPC8240

[Andrew Johnson]

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
thread...

TIA,

- 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

** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/

Re: SSSSlllloooowwww MPC8240

[Jerry Van Baren]

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.

gvb


At 06:57 PM 7/9/01 -0400, anj@aps.anl.gov 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
>thread...
>
>TIA,
>
>- 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
>


** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/

Re: SSSSlllloooowwww MPC8240

[Andrew Johnson]

Jerry Van Baren wrote:
>
> Is caching enabled (both instruction and data)?  It sounds a lot like
> you are running without the benefit of caches.

That was it - thanks Jerry, I now get 133.12 BogoMIPS and a much more
responsive machine.

- 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

** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/