VAnalyser : GPU utilization always at 100%

[sylvainlehenaff]

Hello community,

I am profiling an graphical application and I would like to know what is going on at the GPU level.

I am using a IMX6 Dual and it shows a 100% GPU utilization in the Vanalyser profiler. The GPU driver utilisation varies but I don't understand why the GPU usage figure is always 100%.

Is there an error in the VAnalyser/Profiler for this data ? (VAnalyzer v150)

If this is true, what does it mean ?

When I profile a vivante example (Tiger / coverfloaw ...) the value remains at 100%.

I am using a linux Yocto 3.10.17.

Regards

Sylvain

[Bio_TICFSL]

Hi sylvain,

Check that you are not using the demo image, it doesn't support vprofiler in kernel.

The Vprofiler can only work on Vivante GPU, it needs GPU kernel driver support.For vprofiler.vpd, it is only kernel related, In case of 3.10.17 the OpengVG and 2D APIs, they can't be supported by PC side vAnalyzer and vEmulator.

I strongly recommend to test with latest 3.14.28 o 3.14.38 BSPs.

Hope this helps

[sylvainlehenaff]

Hi,

I have done some test with the profiler and newer driver (3.14.28). The results remains identical, GPU is still at 100% Idle cycle remains at 0.

But looking at the release note of 3.14.52 driver, I have found an errata reagarding Idle cycle....

• General: Fix GPU idle cycles counter for vProfiler

Therefore, I suppose that there was a bug ....

Regards,

[sylvainlehenaff]

Hi,

The kernel used have the support for profiler. I have activated the profiler from the bootargs and then with the "export VIV_PROFILE=1"

The images used are specific to the SMARC Card i am using, they have been built from the partner documention.

2 versions of kernel have been checked. the latest version (3.14.x) are not available for now on for these boards.

I am quite sure that the profiler is working. The problem is that I cannot be sure that the data coming from the GPU are correct. GPU utilization is always 100%. Driver processing time are changing but I would like to have a bit more information at GPU workload.

Either the application is not using correctly the GPU (GC2000) and the figures shows a problem at SW level or the GPU utilization at 100% means realy that the GPU is not powerful enough for what I am doing or that the VAnalyser has a bug .

nb)I have done some tries with the tiger application (just for a try); the VAnalyser provides data for openVG. (I don t know about VCompiler)

regards,

sylvain