From 27739491977c643916f4ca30f71043d74b448f90 Mon Sep 17 00:00:00 2001
From: Wojtek Figat <wojtek@figat.pl>
Date: Sat, 22 Jun 2024 09:58:20 +0200
Subject: [PATCH] Optimize wait signal in Job System to wake waiting threads
 only when job batch ends

---
 Source/Engine/Threading/JobSystem.cpp | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/Source/Engine/Threading/JobSystem.cpp b/Source/Engine/Threading/JobSystem.cpp
index f278d7d02..090bab2ea 100644
--- a/Source/Engine/Threading/JobSystem.cpp
+++ b/Source/Engine/Threading/JobSystem.cpp
@@ -200,16 +200,19 @@ int32 JobSystemThread::Run()
             data.Job(data.Index);
 
             // Move forward with the job queue
+            bool notifyWaiting = false;
             JobsLocker.Lock();
             JobContext& context = JobContexts.At(data.JobKey);
             if (Platform::InterlockedDecrement(&context.JobsLeft) <= 0)
             {
                 ASSERT_LOW_LAYER(context.JobsLeft <= 0);
                 JobContexts.Remove(data.JobKey);
+                notifyWaiting = true;
             }
             JobsLocker.Unlock();
 
-            WaitSignal.NotifyAll();
+            if (notifyWaiting)
+                WaitSignal.NotifyAll();
 
             data.Job.Unbind();
         }