This is the mail archive of the
ecos-discuss@sources.redhat.com
mailing list for the eCos project.
Re: Slow MPC board?
- From: Michael Kelly <mike at cogcomp dot com>
- To: "Daniel Lidsten" <Daniel dot Lidsten at combitechsystems dot com>
- Cc: "eCos Discussion" <ecos-discuss at sources dot redhat dot com>
- Date: Tue, 26 Aug 2003 10:33:31 -0400
- Subject: Re: [ECOS] 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