Fix editor hang on level load (#6323)

Make View::SortFinalizedDrawLists use child jobs so they don't block the worker thread from doing other work while waiting.
Implement a TaskGraph version of the view draw list sort.
Fix a misc bug where the scene was waiting on a task graph event twice and so hanging.
Enable MeshFeatureProcessor::Simulate to be able to use jobs when no parent job is specified because the parent job is a task.

Signed-off-by: rgba16f <82187279+rgba16f@users.noreply.github.com>

Gems/Atom/Feature/Common/Code/Source/Mesh/MeshFeatureProcessor.cpp

@@ -123,11 +123,26 @@ namespace AZ
                     }
                 };
                 Job* executeGroupJob = aznew JobFunction<decltype(jobLambda)>(jobLambda, true, nullptr); // Auto-deletes
-                parentJob->StartAsChild(executeGroupJob);
+                if (parentJob)
+                {
+                    parentJob->StartAsChild(executeGroupJob);
+                }
+                else
+                {
+                    executeGroupJob->SetDependent(&jobCompletion);
+                    executeGroupJob->Start();
+                }
             }
             {
                 AZ_PROFILE_SCOPE(AzRender, "MeshFeatureProcessor: Simulate: WaitForChildren");
-                parentJob->WaitForChildren();
+                if (parentJob)
+                {
+                    parentJob->WaitForChildren();
+                }
+                else
+                {
+                    jobCompletion.StartAndWaitForCompletion();
+                }
             }
 
             m_forceRebuildDrawPackets = false;

Gems/Atom/RPI/Code/Include/Atom/RPI.Public/View.h

@@ -24,6 +24,9 @@ class MaskedOcclusionCulling;
 
 namespace AZ
 {
+    // forward declares
+    class Job;
+    class TaskGraphEvent;
     namespace  RHI
     {
         class FrameScheduler;
@@ -102,7 +105,8 @@ namespace AZ
 
             //! Finalize draw lists in this view. This function should only be called when all
             //! draw packets for current frame are added. 
-            void FinalizeDrawLists();
+            void FinalizeDrawListsJob(AZ::Job* parentJob);
+            void FinalizeDrawListsTG(AZ::TaskGraphEvent& finalizeDrawListsTGEvent);
 
             bool HasDrawListTag(RHI::DrawListTag drawListTag);
 
@@ -142,7 +146,8 @@ namespace AZ
             View(const AZ::Name& name, UsageFlags usage);
 
             //! Sorts the finalized draw lists in this view
-            void SortFinalizedDrawLists();
+            void SortFinalizedDrawListsJob(AZ::Job* parentJob);
+            void SortFinalizedDrawListsTG(AZ::TaskGraphEvent& finalizeDrawListsTGEvent);
 
             //! Sorts a drawList using the sort function from a pass with the corresponding drawListTag
             void SortDrawList(RHI::DrawList& drawList, RHI::DrawListTag tag);

Gems/Atom/RPI/Code/Source/RPI.Public/Scene.cpp

@@ -114,6 +114,7 @@ namespace AZ
             if (m_taskGraphActive)
             {
                 WaitAndCleanTGEvent(AZStd::move(m_simulationFinishedTGEvent));
+                m_simulationFinishedTGEvent.reset();
             }
             else
             {
@@ -383,7 +384,9 @@ namespace AZ
                     simulationTGDesc,
                     [this, featureProcessor]()
                     {
-                        featureProcessor->Simulate(m_simulatePacket);
+                        FeatureProcessor::SimulatePacket jobPacket = m_simulatePacket;
+                        jobPacket.m_parentJob = nullptr;
+                        featureProcessor->Simulate(jobPacket);
                     });
             }
             simulationTG.Detach();
@@ -423,6 +426,7 @@ namespace AZ
             if (m_taskGraphActive)
             {
                 WaitAndCleanTGEvent(AZStd::move(m_simulationFinishedTGEvent));
+                m_simulationFinishedTGEvent.reset();
             }
             else
             {
@@ -609,9 +613,9 @@ namespace AZ
             {
                 finalizeDrawListsTG.AddTask(
                     finalizeDrawListsTGDesc,
-                    [view]()
+                    [view, &finalizeDrawListsTGEvent]()
                     {
-                        view->FinalizeDrawLists();
+                        view->FinalizeDrawListsTG(finalizeDrawListsTGEvent);
                     });
             }
             finalizeDrawListsTG.Submit(&finalizeDrawListsTGEvent);
@@ -623,9 +627,9 @@ namespace AZ
             AZ::JobCompletion* finalizeDrawListsCompletion = aznew AZ::JobCompletion();
             for (auto& view : m_renderPacket.m_views)
             {
-                const auto finalizeDrawListsLambda = [view]()
+                const auto finalizeDrawListsLambda = [view](AZ::Job& job)
                 {
-                    view->FinalizeDrawLists();
+                    view->FinalizeDrawListsJob(&job);
                 };
 
                 AZ::Job* finalizeDrawListsJob = AZ::CreateJobFunction(AZStd::move(finalizeDrawListsLambda), true, nullptr);     //auto-deletes
@@ -642,6 +646,7 @@ namespace AZ
             if (m_taskGraphActive)
             {
                 WaitAndCleanTGEvent(AZStd::move(m_simulationFinishedTGEvent));
+                m_simulationFinishedTGEvent.reset();
             }
             else
             {
@@ -743,7 +748,7 @@ namespace AZ
                 {
                     for (auto& view : m_renderPacket.m_views)
                     {
-                        view->FinalizeDrawLists();
+                        view->FinalizeDrawListsJob(nullptr);
                     }
                 }
                 else

Gems/Atom/RPI/Code/Source/RPI.Public/View.cpp

@@ -21,6 +21,7 @@
 #include <AzCore/Serialization/SerializeContext.h>
 #include <AzCore/Jobs/JobCompletion.h>
 #include <AzCore/Jobs/JobFunction.h>
+#include <AzCore/Task/TaskGraph.h>
 #include <Atom_RPI_Traits_Platform.h>
 
 #if AZ_TRAIT_MASKED_OCCLUSION_CULLING_SUPPORTED
@@ -253,14 +254,45 @@ namespace AZ
             return m_drawListContext.GetList(drawListTag);
         }
 
-        void View::FinalizeDrawLists()
+        void View::FinalizeDrawListsTG(AZ::TaskGraphEvent& finalizeDrawListsTGEvent)
         {
             AZ_PROFILE_SCOPE(RPI, "View: FinalizeDrawLists");
             m_drawListContext.FinalizeLists();
-            SortFinalizedDrawLists();
+            SortFinalizedDrawListsTG(finalizeDrawListsTGEvent);
+        }
+        void View::FinalizeDrawListsJob(AZ::Job* parentJob)
+        {
+            AZ_PROFILE_SCOPE(RPI, "View: FinalizeDrawLists");
+            m_drawListContext.FinalizeLists();
+            SortFinalizedDrawListsJob(parentJob);
         }
 
-        void View::SortFinalizedDrawLists()
+        void View::SortFinalizedDrawListsTG(AZ::TaskGraphEvent& finalizeDrawListsTGEvent)
+        {
+            AZ_PROFILE_SCOPE(RPI, "View: SortFinalizedDrawLists");
+            RHI::DrawListsByTag& drawListsByTag = m_drawListContext.GetMergedDrawListsByTag();
+
+            AZ::TaskGraph drawListSortTG;
+            AZ::TaskDescriptor drawListSortTGDescriptor{"RPI_View_SortFinalizedDrawLists", "Graphics"};
+            for (size_t idx = 0; idx < drawListsByTag.size(); ++idx)
+            {
+                if (drawListsByTag[idx].size() > 1)
+                {
+                    drawListSortTG.AddTask(drawListSortTGDescriptor, [this, &drawListsByTag, idx]()
+                    {
+                        AZ_PROFILE_SCOPE(RPI, "View: SortDrawList Task");
+                        SortDrawList(drawListsByTag[idx], RHI::DrawListTag(idx));
+                    });
+                }
+            }
+            if (!drawListSortTG.IsEmpty())
+            {
+                drawListSortTG.Detach();
+                drawListSortTG.Submit(&finalizeDrawListsTGEvent);
+            }
+        }
+
+        void View::SortFinalizedDrawListsJob(AZ::Job* parentJob)
         {
             AZ_PROFILE_SCOPE(RPI, "View: SortFinalizedDrawLists");
             RHI::DrawListsByTag& drawListsByTag = m_drawListContext.GetMergedDrawListsByTag();
@@ -276,11 +308,25 @@ namespace AZ
                         SortDrawList(drawListsByTag[idx], RHI::DrawListTag(idx));
                     };
                     Job* jobSortDrawList = aznew JobFunction<decltype(jobLambda)>(jobLambda, true, nullptr); // Auto-deletes
-                    jobSortDrawList->SetDependent(&jobCompletion);
-                    jobSortDrawList->Start();
+                    if (parentJob)
+                    {
+                        parentJob->StartAsChild(jobSortDrawList);
+                    }
+                    else
+                    {
+                        jobSortDrawList->SetDependent(&jobCompletion);
+                        jobSortDrawList->Start();
+                    }
                 }
             }
-            jobCompletion.StartAndWaitForCompletion();
+            if (parentJob)
+            {
+                parentJob->WaitForChildren();
+            }
+            else
+            {
+                jobCompletion.StartAndWaitForCompletion();
+            }
         }
 
         void View::SortDrawList(RHI::DrawList& drawList, RHI::DrawListTag tag)