mpc8548 does not make use of DMA when doing memory copy?

[hank peng]

2009/11/3 Micha Nelissen <micha at neli.hopto.org>:
> hank peng wrote:
>>
>> I remember normal memory copy can also be done (chosen by user) by DMA
>> engine on IOP80331(Intel embedded cpu, xscale arch), so why ppc
>> platform didn't make use of DMA doing memory copy, I think it can
>> increase performance, please correct me if I am wrong!
>
> AFAIK the DMA engine has only an asynchronous mode (not very smart IMHO).
> This means you always have the overhead of context switch + interrupt +
> context switch, so the transfer has to be quite large for this to pay off.
>
but if the amount of data I want to copy is big enough? can we benefit
from using DMA in such case?
> Micha
>



-- 
The simplest is not all best but the best is surely the simplest!