Question [AsyncGPUReadback] huawei Y5 prime, Gfx.RequestAsyncReadbackData takes 35 ms to complete

Hi,

I'm investigating a perf issue on huawei Y5 prime (dra-al00). I use AsyncGPUReadback.Request to read a small texture of 128*128 from GPU. It surprisingly takes about 35ms to complete the request and meanwhile blocks the render thread. This causes severe framerate dropping (from 30fps to 20fps).

I have tested the same code on various devices (same tier low end ones, eg. Quad-core CPUs, PowerVR GE8100...). Y5 prime is the only one that has this issue. On other devices, AsyncGPUReadback takes about 3-5ms.

I also tried to fire the request at a lower frequency, eg, every 4 frames. But it doesn't help, AsyncGPUReadback still takes 35ms every time.

Any ideas/suggestions to try would be very welcome, or if any Unity employee could explain a little more about AsyncGPUReadback (known issue, limitation?) so I could know what to try next.

I'm using Unity 2021.3.9f1 LTS.

Y5 prime spec:
Android 8.1 (Oreo), EMUI 8
Mediatek MT6739 (28 nm)
Quad-core 1.5 GHz Cortex-A53
PowerVR GE8100
Note: Intalled 64bit app

pic1: Y5 prime AsyncGPUReadback on


pic2: Y5 prime AsyncGPUReadback off


pic3: lm-k200 AsyncGPUReadback on
lm-k200 spec:
Android 10
Qualcomm QM215 Snapdragon 215 (28 nm)
Quad-core 1.3 GHz Cortex-A53
Adreno 308
Note: Intalled 32bit app


Thanks

 

Hi check out this post and see if it helps you (let us know!) I did have a thread here in Graphics but it was deleted! (If any mods are reading this can you move my post back to Graphics?)

https://forum.unity.com/threads/ple...mode-monitor-refresh-rate-by-default.1353761/

 

Thanks for the reply.

I think this option (Interaction Mode) is for Editor as the doc says:

"Specifies how long the Editor can idle before it updates. After one frame finishes, the Editor waits up to the specified amount of time before the next frame begins.

This allows you to throttle Editor performance, and reduce consumption of CPU resources and power.

For example, if you want to test the Editor’s performance, set this property to No Throttling. If you want to conserve power (for example, to prolong battery life on a laptop computer), set this property to one of the throttled modes.

In throttled modes, the Editor stops idling if you interact with it (for example, by panning in the Scene view)."

 

It looks like a bug, but might be driver/Android not Unity related.

Is one OpenGL ES and the other one Vulkan maybe?

 

They both use OpenGLES3. lol