Re: [ECOS] Slow MPC board?

[Michael Kelly <mike at cogcomp dot com>]

Frank,

While the UPM is the same on all MPC8xx's, the CMA did 
not use the UPM.  Instead there was an external SDRAM 
controller located on the CMA motherboard.  This offered
much higher bandwidth than the UPM and supported page
mode, open banks, etc., that I don't think the UPM did.  So,
there really is a significant difference in the memory performance
between the two boards.

Michael

At 11:00 AM 8/26/2003, Frank Robbins wrote:

>----- Original Message ----- 
>From: "Gary Thomas" <gary@mlbassoc.com>
>To: "Daniel Lidsten" <Daniel.Lidsten@combitechsystems.com>
>Cc: "eCos Discussion" <ecos-discuss@sources.redhat.com>
>Sent: Tuesday, August 26, 2003 3:31 PM
>Subject: Re: [ECOS] Slow MPC board?
>
>
>> On Tue, 2003-08-26 at 08:16, Daniel Lidsten wrote:
>> > Hi,
>> >
>> > I think that my board is quite slow but i cannot find why. When i look
>> > in the user manual/realtime characterization for the Cogent CMA MPC860
>> > 33Mhz then i find it much faster then my MPC823e 50Mhz. The cogent board
>> > handles a clock interrupt in 14 us, i do it in 50us. A thread switch
>> > takes 7.5us on the cogent board and 14us on my board.
>> >
>> > The above big difference goes through all measurements - my board is
>> > clocked faster then the cogent board but have half the performance. I
>> > have the caches (both I and D) enabled.
>> >
>> > Ideas? Can it be any configuration issue?
>> >
>>
>> It could be DRAM timings - does the 823 use a UPM?
>
>Frank:-) Is the Core deserialised ?
>
>The UPM is as all MPC8XX processors  there should be no difference
>
>>
>> -- 
>> Gary Thomas <gary@mlbassoc.com>
>> MLB Associates
>>
>>
>> -- 
>> Before posting, please read the FAQ: http://sources.redhat.com/fom/ecos
>> and search the list archive: http://sources.redhat.com/ml/ecos-discuss
>>
>
>
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>Before posting, please read the FAQ: http://sources.redhat.com/fom/ecos
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Michael J. Kelly
VP Engineering/Marketing
Cogent Computer Systems, Inc.
1130 Ten Rod Road
Suite A-201
North Kingstown, RI 02852
tel:401-295-6505 fax:401-295-6507
www.cogcomp.com
alternate email: mkelly6505@hotmail.com


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