AsyncGPUReadback Hitching on Gfx.UpdateAsyncReadbackData

Unity Engine
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1

Was trying to optimize getting data off the gpu just in case but while using ComputeBuffer.GetData completes without really hitching anything, for some reason using AsyncGPUReadback does the opposite of what it’s supposed to and freezes the game entirely.
Here’s the profiler on one of the hitches.

8721003--1179177--upload_2023-1-10_18-6-57.png
8721003--1179177--upload_2023-1-10_18-6-57.png2226×1494 298 KB

And here’s the code I’m using

8721003--1179180--upload_2023-1-10_18-24-18.png
8721003--1179180--upload_2023-1-10_18-24-18.png2341×534 78.1 KB

Not sure what to make of this.
I’m running the latest 2019LTS version, not sure if this is something that’d be fixed in later versions but don’t really have that option anyway.
At this point I’d just want someone to sanity check me and tell me if it’s just broken or what.

2

I have the same problem, I tried to optimize some work by putting it async but getting data back with readbacks ends up being very slow with this problem

3

Same issue. Very frustrating.

4

This is, in my experience, most often caused by particle systems. Had MANY of these in 2019, in various versions of it.

5

I’ll ping @richardkettlewell as I think he knows more about this than anyone.

6

I’ve no idea, other than yeah it looks like a bug. It doesn’t look very async :slight_smile:

If you’re able to submit a bug report, the team that owns this can take a look.