J784S4XEVM: DMA copy speeds: DMA Linux driver vs UDMA on R5F in the J784S4 platform

Hi Ninh,

If you are using same type of DMA channels on both the cores, the performance should be exactly same or atleast similar, are you sure you are using same kind of channels? What about timer with which you are measuring the performance? 

Regards,

Brijesh 

Hi Brijesh Jadav,
I found that DSP using the DRU, if I disable DRU support on UDMA of DSP
the speed is the same with DMA on A72. Do J784s4 linux support DRU ?

BRs,
Ninh Nguyen

Hi Ninh,

So you mean, you are using DRU channels on DSP and doing some transfer on DSP using these channels? Then it can potentially affect performance. 

I really doubt Linux supports DRU channels. 

Regards,

Brijesh 

Hi Brijesh Jadav,
I check the ti rtos, on DSP side, it using UDMA t transfer data from DDR to L2 or somethings place, it default using DRU for UDMA
=> The speed of DSP DMA is fast with around 10 to 14 GB/s.
When I disable DRU on DSP, speed go down and the same with Dma linux driver.

  "I really doubt Linux supports DRU channels. "
=> Can you check it with the J784s4 SDK version 9 for DRU support ? and is there any guide or document to support DRU on linux ?

Thanks
BRs,

Ninh Nguyen

Hi Ninh,

DRU on DSP will give better performance, so should not compare with DRU channels. 

No there is no support for DRU channels on Linux. 

Regards,

Brijesh

Hi Brijesh Jadav,
"No there is no support for DRU channels on Linux. "
So it not implement support on Linux (A72) or It cannot use in A72 ?

Hi Ninh,

It is not supported in Linux. 

Regards,

Brijesh