About performance optimization regarding memcpy

Question

Hi, EW team:

      In my Autosar project, I have EwProcess scheduled in a task of the lowest priority, so all other tasks can preempt it. When bitmap resource is loaded from external Norflash with EwCopy, preemption will interrupt the loading as well. To make use of the preemption time, I'd like to replace memcpy() with a DMA copy. So my questions are:

     1. Is this idea applicable?

    2. If yes, what should I take care of when implementing the DMA copy? Invalidating cache is my only concern now. I don't know if there is any potential violation against EW platform.

 

Thank you.

Best regards.

Stephen

Answer 1

Hi Stephen,

according to your description, you intend to use the DMA in a synchronous manner - this means, the GUI task will not continue until the DMA has completed the transfer. Just other tasks are using the CPU time. In this case I do not see any obstacles here. As you already mentioned, the address range of the DMA destination has to be invalidated for the D-Cache.

Best regards,

Manfred.

Comments

Hi，Manfred:

      That's what I intend to d.

     Thank you.

 

Best regards.

Stephen