Overhead/Delay when repeatedly calling DSP codec on DM6441

JasonD3

I am trying to process an image in blocks and I am repeatedly calling my DSP codec in a loop. There seems to be a massive amount of overhead in making the "VIDDEC1_process" call. I am seeing ~25 ms of time from when the process call is made by the ARM to when the DSP actually starts processing. There is then another ~5 ms of time from when the DSP is done with processing before the ARM continues its operations. This seems really excessive to just be overhead, so I was wondering if there is some kind of setup that I missed that may be causing this. Is the DSP set up by default to maybe only look for process calls on a 30 fps frame time basis? Any help with this is greatly appreciated.

Thanks,

Jason

over 16 years ago

0 Chris Ring over 16 years ago

TI__Genius 17205 points

This may help:

http://tiexpressdsp.com/index.php/Codec_Engine_Overhead

What size buffers, and how many, are you sending in each process call? If you're using DMA to access the buffers (from your DSP-side codec), and therefore don't require DSP-side cache maintenance, the article above describes how to remove that cache mgmt overhead.

Chris

0 JasonD3 over 16 years ago in reply to Chris Ring

Intellectual 750 points

Chris,

Thanks, this helped a lot. I was able to reduce the overhead time to ~150 us before the process call and ~250 us after the process call. This is still pretty high compared to the benchmarks that are shown on the wiki page, but acceptable for now.

Thanks again,

Jason

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Overhead/Delay when repeatedly calling DSP codec on DM6441