Re: PowerPC/VME64

[Nick Dillon <nd14@ast.cam.ac.uk>]

Peregrine,

> 2) Also, if anyone has experience with VME64 systems I'd like to know
> what the _real_ measured transfer rates are.

Under VxWorks I typically get a little over 30MByte/s average throughput
in a test in which a largish message (few Mbytes) gets ping-ponged between
2 CPUs using D64 block transfers. This includes overheads associated with
signalling between the CPUs; you could do significantly better if a slave
were just swallowing D64 blocks. Also, my application uses a device driver
to manage the transfers and this luxury degrades raw VME throughput
further. Nevertheless, if you intend to transfer rather small blocks
and/or have much else contending for the bus I wouldn't budget for _very_
much more throughput.

(These results were with MV167<-->Baja4700 transfers.)

Regards,
Nick Dillon.
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