Add customizable per-platform affinity for content and pool threads

Source/Engine/Threading/ThreadPool.cpp

@@ -28,6 +28,9 @@ namespace ThreadPoolImpl
     ConcurrentTaskQueue<ThreadPoolTask> Jobs; // Hello Steve!
     ConditionVariable JobsSignal;
     CriticalSection JobsMutex;
+#ifdef THREAD_POOL_AFFINITY_MASK
+    volatile int64 ThreadIndex = 0;
+#endif
 }
 
 String ThreadPoolTask::ToString() const
@@ -63,11 +66,12 @@ bool ThreadPoolService::Init()
     PROFILE_MEM(EngineThreading);
 
     // Spawn threads
-    const int32 numThreads = Math::Clamp<int32>(Platform::GetCPUInfo().ProcessorCoreCount - 1, 2, PLATFORM_THREADS_LIMIT / 2);
-    LOG(Info, "Spawning {0} Thread Pool workers", numThreads);
-    for (int32 i = ThreadPoolImpl::Threads.Count(); i < numThreads; i++)
+    const CPUInfo cpuInfo = Platform::GetCPUInfo();
+    const int32 count = Math::Clamp<int32>(cpuInfo.ProcessorCoreCount - 1, 2, PLATFORM_THREADS_LIMIT / 2);
+    LOG(Info, "Spawning {0} Thread Pool workers", count);
+    ThreadPoolImpl::Threads.Resize(count);
+    for (int32 i = 0; i < count; i++)
     {
-        // Create tread
         auto runnable = New<SimpleRunnable>(true);
         runnable->OnWork.Bind(ThreadPool::ThreadProc);
         auto thread = Thread::Create(runnable, String::Format(TEXT("Thread Pool {0}"), i));
@@ -76,9 +80,7 @@ bool ThreadPoolService::Init()
             LOG(Error, "Failed to spawn {0} thread in the Thread Pool", i + 1);
             return true;
         }
-
-        // Add to the list
-        ThreadPoolImpl::Threads.Add(thread);
+        ThreadPoolImpl::Threads[i] = thread;
     }
 
     return false;
@@ -110,6 +112,10 @@ void ThreadPoolService::Dispose()
 
 int32 ThreadPool::ThreadProc()
 {
+#ifdef THREAD_POOL_AFFINITY_MASK
+    const int64 index = Platform::InterlockedIncrement(&ThreadPoolImpl::ThreadIndex) - 1;
+    Platform::SetThreadAffinityMask(THREAD_POOL_AFFINITY_MASK((int32)index));
+#endif
     ThreadPoolTask* task;
 
     // Work until end