FPS issues depending on unity version when using vive pro2

[unityKing]

We are currently developing with the Vive Pro 2 in Unity and have encountered FPS issues with different Unity versions. After conducting several tests, we have observed the following results:

Case 1: Unity Version 2020.3.12f1 (URP)

• Frames per second (FPS): Normal

Case 2: Unity Version 2022.3.5f1 (URP)

• FPS: Irregular or very low

Case 3: Unity Version 2023.1.10f1 (URP)

• FPS: Irregular or very low

We are reaching out to seek your expertise on understanding why such anomalies are occurring and to inquire about potential solutions. It seems that the issue is specifically tied to Unity versions 2022.3.5f1 and 2023.1.10f1, where the FPS becomes irregular or significantly decreases.

If you could provide insights into the root cause of this behavior and suggest possible solutions, it would be greatly appreciated. Additionally, if there are any updates, patches, or best practices related to the Unity integration with Vive Pro 2, we would like to ensure that our development aligns with the recommended configurations.

Thank you in advance for your assistance. We are looking forward to resolving this matter promptly to continue our development smoothly.

Best regards,

[Alex_HTC]

@unityKing

Howdy! It is always frustrating dealing with performance issues.

The hardest part is isolating a specific portion of your code that responds to changes.

Looking quickly, my guess is that either adaptive performance or some detail of the upgrade instructions across these versions of urp need to be followed: https://docs.unity3d.com/Packages/com.unity.render-pipelines.universal@16.0/manual/upgrade-guides.html 

Ok, so now you've identified unity and perhaps versions as a variable! So we have some clues that point to the URP and it's dependencies(ie render pipeline, burst, or the project version shaders/effects themselves on rare occasion.
So it looks like unity's been changing things for the past 3 years, let's see just for the universal pipeline:
https://docs.unity3d.com/Packages/com.unity.render-pipelines.universal@16.0/changelog/CHANGELOG.html

Looking at just 'performance' related issues, adaptive performance was added - so may want to make sure this is 'off' in newer versions to rule this out as a factor.


First off, let's look at some potential issues that could happen when auto updating:
https://docs.unity.cn/Packages/com.unity.render-pipelines.universal@12.1/manual/known-issues.html
and let's make sure that the shaders/related ifdefs/etc are updated when changing the versions (as the auto-updater may change and/or add fixes as well) https://docs.unity3d.com/Packages/com.unity.render-pipelines.universal@10.0/manual/upgrading-your-shaders.html and https://docs.unity3d.com/Packages/com.unity.render-pipelines.universal@16.0/manual/features/rp-converter.html

if we look at https://docs.unity.cn/Packages/com.unity.render-pipelines.universal@12.1/manual/requirements.html we can see that the relevant urp versions are directly related to the editor version.
2020.3.12 - Urp package version range: 10.x
2022.3.5 - URP package version 14.0.x
2023.1.10f1 -  URP package version 16.0.x

There is instructions for updating across versions here https://docs.unity3d.com/Packages/com.unity.render-pipelines.universal@16.0/manual/upgrade-guides.html that goes in detail for each version, these may be different and require re-running across new versions.


Other tools to figure out performance issues

1. Profiler - See what is different at a high level - cpu, gpu, etc. this points to where the bottleneck may be at a high level
2. Memory profiler - overview - with different versions may come different usage of temporary buffers/etc. shuffling bits around is expensive - this can point to mis-matched texture sizes
3. Frame debugger - let's see exactly how the rendering is different if that's the issue https://docs.unity3d.com/Manual/FrameDebugger.html 
4. Other resources
    

Other potential factors
- what version of the wave or openxr sdk is being used across these different versions as well
-double check the same quality settings are being used across projects (as this is also how the adaptive performance stuff worked, this seems likely - removing all other qualtiy settings would likely help eliminate this factor)

-does this also happen if the project is on the built-in render pipeline?
-other dependencies of the rendering pipeline and their related changes

 

[unityKing]

howdy!

 

Based on the conducted tests under the specified conditions, it was observed that the frames appeared normal when only camera lighting was added to an empty scene without using URP. Consequently, the current issue is suggested to be unrelated to the conversion process.

Given that the symptoms did not occur when URP was not utilized, it is believed that the problem may be attributed to a different cause. Further analysis of URP's characteristics, settings, and other environmental factors is deemed necessary to identify the root cause. If you could provide more detailed information or insights for developing a strategy to address the issue, it would be greatly appreciated.

Thank you.

[Alex_HTC]

@unityKingMy first step would be to eliminate the adaptive quality settings, both by removing that option from newer versions of urp and by removing all other quality settings.

When it comes to other optimizations,  the specific subsystems impacted woudl be teh start - is it extra memory, too much cpu, etc

Links for relevant resources are in the above post as well. Those would be a starting point before the unity forums or other urp-adjacent tech communities like the urp forum would be able to help.

Thanks,
Alex