(IN-87175) GraphicsStateCollection Tracing causes crash

Unity Engine
, , , , , ,
1

Calling GraphicsStateCollection.GetVariants on a GraphicsStateCollection that was used to trace is causing the engine to crash. I’m using Unity 6000.0.23 and URP. It crashes in the editor and windows builds.

I have submitted bug-report IN-87175 with several crash dumps for you to inspect.

Here is the code snippet that causes the crash, the way how I implemented it follows the advice given by Unity staff here:

// Start trace when level starts
m_GraphicsStateCollection = new GraphicsStateCollection();
m_GraphicsStateCollection.BeginTrace();

// Playing game...

// End trace when level ended and proceeds to next scene
m_GraphicsStateCollection.EndTrace();

var variants = new List<GraphicsStateCollection.ShaderVariant>();
m_GraphicsStateCollection.GetVariants(variants); // This line crashes

The reason why I call GetVariants is that I want to merge it with existing graphics state collections, so that I can feed it new data incrementally with each play.

The error message:

image
image838×529 15.7 KB

The relevant editor stack trace:

(KERNELBASE) RaiseException
(Unity) LaunchBugReporter
(Unity) EditorMonoConsole::LogToConsoleImplementation
(Unity) EditorMonoConsole::LogToConsoleImplementation
(Unity) DebugStringToFilePostprocessedStacktrace
(Unity) DebugStringToFile
(Unity) MemoryManager::Allocate
(Unity) malloc_internal
(Unity) core::StringStorageDefault<char>::grow
(Unity) GraphicsStateCollection::KeywordsFromShaderAndKeywordNames
(Unity) GraphicsStateCollection::GetVariants
(Unity) GraphicsStateCollection_CUSTOM_GetVariants
(Mono JIT Code) (wrapper managed-to-native) UnityEngine.Experimental.Rendering.GraphicsStateCollection:GetVariants_Injected (intptr,UnityEngine.Experimental.Rendering.GraphicsStateCollection/ShaderVariant[])
(Mono JIT Code) UnityEngine.Experimental.Rendering.GraphicsStateCollection:GetVariants (UnityEngine.Experimental.Rendering.GraphicsStateCollection/ShaderVariant[])
(Mono JIT Code) UnityEngine.Experimental.Rendering.GraphicsStateCollection:GetVariants (System.Collections.Generic.List`1<UnityEngine.Experimental.Rendering.GraphicsStateCollection/ShaderVariant>)

The relevant build stacktrace:

(UnityPlayer) GraphicsStateCollection::KeywordsFromShaderAndKeywordNames
(UnityPlayer) GraphicsStateCollection::GetVariants
(UnityPlayer) GraphicsStateCollection_CUSTOM_GetVariants

Is this a bug or is the way how I use it incorrect?

EDIT: I also just realized I can’t merge GraphicsStateCollection’s because there is no API to check if a GraphicsState is added to a Variant already. I guess I have to come up with something that doesn’t require a merge…

2

It seems I have it working now.

I now use the same GraphicsStateCollection during each level to load, warmup, trace and save. This way it’s already incremental and I don’t have to merge different GraphicsStateCollections.

Previously I used a separate GraphicsStateCollection to load/warmup and another one to trace/save.

2 Likes
3

Hi, do you assign your graphics state collection to a field and warm that up? Or do you load the file using GraphicsStateCollection.LoadFromFile?

I’m trying to figure out if LoadFromFile is necessary.

Thanks!

4

This is how I’m using it, but I’m not sure if it aligns with Unity’s best practices :slightly_smiling_face:

class ShaderWarmupBehaviour : MonoBehaviour
{
    JobHandle? m_JobHandle;
    
    void OnEnable()
    {
        StartCoroutine(Worker());
    }

    void OnDisable()
    {
        if (m_JobHandle.HasValue)
        {
            if (!m_JobHandle.Value.IsCompleted)
                m_JobHandle.Value.Complete();
            m_JobHandle = null;
        }
    }
            
    System.Collections.IEnumerator Worker()
    {
        var filePath = "<path to graphics state collection>";
        var graphicsStateCollection = new GraphicsStateCollection(filePath);

        m_JobHandle = graphicsStateCollection.WarmUp();
        while (!m_JobHandle.Value.IsCompleted)
        {
            // In my project, this keeps the loading screen visible
            // while the warmup process is still running.
            LoadUtility.waitFrame = true; 
            yield return null;
        }
    }
}
5

thanks! I think the way I am doing it (assigning the collection a field directly) works, unfortunately we have an issue where the tracing is not pickup up a substantial number of the variants/graphics states. Have you run into this same issue?

6

I don’t know, I haven’t looked at it in detail for a long time. How would I notice that variants are missing?

7

You would most likely have stuttering which you’d trace back (via the profiler) to the pipeline creation (can’t remember the Profiler Marker for this).

No worries, thanks a lot for taking the time to reply!