IMX6 - Impact of CPU frequency on GC2000 frequency

[sylvainlehenaff]

Hello community,

I am currently working with the IMX6 on a graphic project and I have some question regarding the behavior of the GPU wrt to the ARM part of the IMX6.

When I deploy a graphical application at various ARM frequency (792MHz, 996MHz, 1.2GHz) the time needed to compute the graphic is reduced but the frame rate doesn't changed.

I am kind of stuck around 50Hz and I cannot managed to go higher. The ARM can go faster but the GPU is not following...Graphic part representing around 5ms on the ARM, I would expect a much higher frame rate.

Is there an impact of the ARM frequency on the GPU frequency ?

I have observed this on a sabre lite (Yocto 3.10.53 with galcore v5.x) and on a SMARC from Kontron (Yocto 3.10.17 with galcore v4.9x)

Regards

Sylvain

[igorpadykov]

HI sylvain

gpu works independently from cpu and its frequency

does not affect gpu performance. 50Hz is quite decent figure,

limit may be caused by ddr/buses bandwidth,

also some performance figures can be found on

https://community.freescale.com/docs/DOC-93612

Best regards

igor

-----------------------------------------------------------------------------------------------------------------------

Note: If this post answers your question, please click the Correct Answer button. Thank you!

-----------------------------------------------------------------------------------------------------------------------

[sylvainlehenaff]

Hi Igor,

I have done some bench on the IMX6, but i still not happy by the GPU.

With a simple application using a loop {Draw,glush , swap} The refresh rate seems limited to a 45-50Hz altough the "draw" performed by the ARM is less than 3ms.

It is true that if I change the frequency of the ARM, the value for the draw is reduced (but the frame rate does not change), this confirm your answer.

But, I still don't undersatnd why a simple application taking 3ms on the ARM cannot go higher than 50Hz ?

The application is running at 800x600 on ES2.0, so it should be OK for any issue regarding the bandwidth....

regards,

Sylvain