This is the mail archive of the ecos-discuss@sources.redhat.com mailing list for the eCos project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: Slow MPC board?


Daniel,

Other than the Cogent hardware being so superior.... just kidding.;-)

Seriously the main issue may be that the Cogent board uses 64-Bit SDRAM
running off the MPC860 bus with full bursting enabled.  The 823e may 
be using only 32-Bit SDRAM and may not be burst enabled or you
might even be running from rom/flash!  The caches on the MPC8xx
are fairly small (4K IIRC) so main memory bandwidth is very important.

One more thing, the 823e has 16K I-Cache an d8K D-Cache, but the non
e version has 2K/1K.  Are you sure you have them configured correctly
in eCos for the 823e?

Michael

At 10:16 AM 8/26/2003, 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?
>
>Regards, Daniel Lidsten
>
>-- 
>Before posting, please read the FAQ: http://sources.redhat.com/fom/ecos
>and search the list archive: http://sources.redhat.com/ml/ecos-discuss

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


-- 
Before posting, please read the FAQ: http://sources.redhat.com/fom/ecos
and search the list archive: http://sources.redhat.com/ml/ecos-discuss


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]