GAM percentage is too high when using VA i965 driver with help of Gstreamer Vaapi plugin for Decoding and Encoding.

[APrashant]

Hi,

We are using Intel X86 architecture for our Project.
Build System : Yocto 2.1
VA_DRIVER = i965
We are using Gstreamer pipeline with VAAPI H264 plugins for Decoding, Encoding and Display ( vaapisink ), for 8 H264 input streaming processed parallelly.

We observed GAM % is too high for 8 input streams, when try to get performance using intel_gpu_top tool.

Render Busy = 47%
GAM = 97%
CS = 48%

Since our requirement is to use 16 input streams, we could not able to add more than 8 streams, due to GAM% is too high.

We understand that GAM is similar to TLB, and suspecting, if we increase PAGE_SIZE from 4K to 16K or 64K, then performance might be improved.

Also, we are liking to know the following information.

1. Whether GAM and CPU is having common PAGE SIZE values.
2. How to increase the PAGE SIZE values for GPU processing, for the above mentioned scenario.
3. Whether there is common memory for both CPU and GPU, if yes, whether we can resize the memory, as we mainly using GPU for our purpose.

Is there any other factor will affect the GAM %, if yes, shall you please share the details and help us in resolving this issue.

Also, is there any other tool to get the memory details for GPU processing. Like /proc/meminfo for CPU processing.

[kraj]

perhaps its better to ask this question also at [email protected].