VAnalyser on IMX6 : interpretation of frame time/rate and GPU utilisation ?

[sylvainlehenaff]

Hello,

I currently profiling a graphical application on two SMARC with IMX6, and I am currently having trouble to really understand some behavior observed with the vivante profiler.

My configuration are IMX6 SMARC with a Yocto 3.10.17 with a galcore 4.9x and a SMARC with a Yocto 3.10;53 with a galcore v5.x.

I would like to know what mean the GPU utilisation and the frame time in the profiler ?

What part of the graphical chain is  measured by the frame time ? is it the time when the GPU start and provide the image to the next stage or until it is output ?

The GPU utilisation is always at 100%, which looks strange with the application profiled.

When I look to the graphics, I can see some peaks that I cannot explain.

It is like the graphic has to wait some sync sometime (i can observed some peaks at +16ms comparaing to the average value)

Do we have access to some configuration of VSYNC with the GPU ?

The application is stable and the graphic computed is not changing very fast, therefore the workload can be considered as similar along the test.

This kind of behavior has been observed on both HW.

I cannot explain the chart. I need a stable frame time and for now on, I do not know what to think about this.

Regards,

Sylvain

[sylvainlehenaff]

Hi,

I have two available boards with two version of the kernel. I have ran the tests on both hardwares.

galcore.gpuProfiler=1 have been set at bootargs level (in the u-boot)

The kernel used are 3.10.53 and 3.10.17.

I have download  the package for 3.10.53 from the freescale web site but I have found that in the VTK package (1.6), the VProfiler is in version 1.5

Is it normal ?

When you write about the VTK package v1.6 does it also mean VAnayser v1.6 ?

I recheck the VPD file with this version of VAnalyser but I have still the GPU utilization at 100%.

regards,

Sylvain

[Bio_TICFSL]

Hi Sylvian,

Make sure that you are using the proper VTK tool for the proper BSP version you are using, as example:

3.10.53-1.1-GA contains gpu driver 5.0.11p4, this gpu driver version works with Vivante VTK 1.6.1v

3/.10.17 works with 1.5.0

It also includes a user guide for proper usage of the vTools:

i.MX6Q|i.MX 6Quad Processors|Quad Core|Freescale

Also check if you activate your v profiling functionality:

   insmod /system/lib/modules/galcore.ko gpuProfiler=1

In your profiling graphic, by default the vprofiler open a second tab with the works on synchronous mode, to get values directly from GPU counters frame list of variables and percentage of GPU utilization.

Hope this helps