From 68b3382ef7e0f7795b9a601aae73adc2f8ef9873 Mon Sep 17 00:00:00 2001
From: Dan Engelbrecht <dan@engelbrecht.com>
Date: Wed, 29 Nov 2023 09:14:57 -0500
Subject: global thread worker pools (#577)

- Improvement: Use two global worker thread pools instead of ad-hoc creation of worker pools
---
 src/zenutil/workerpools.cpp | 89 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 89 insertions(+)
 create mode 100644 src/zenutil/workerpools.cpp

(limited to 'src/zenutil/workerpools.cpp')

diff --git a/src/zenutil/workerpools.cpp b/src/zenutil/workerpools.cpp
new file mode 100644
index 000000000..b511b0c5c
--- /dev/null
+++ b/src/zenutil/workerpools.cpp
@@ -0,0 +1,89 @@
+// Copyright Epic Games, Inc. All Rights Reserved.
+
+#include "zenutil/workerpools.h"
+
+#include <zencore/intmath.h>
+#include <zencore/thread.h>
+
+ZEN_THIRD_PARTY_INCLUDES_START
+#include <gsl/gsl-lite.hpp>
+ZEN_THIRD_PARTY_INCLUDES_END
+
+namespace zen {
+namespace {
+	const int LargeWorkerThreadPoolTreadCount = gsl::narrow<int>(std::thread::hardware_concurrency());
+	const int SmallWorkerThreadPoolTreadCount = gsl::narrow<int>(Max((std::thread::hardware_concurrency() / 4u), 1u));
+
+	RwLock PoolLock;
+
+	std::unique_ptr<WorkerThreadPool> LargeWorkerPool;
+	std::unique_ptr<WorkerThreadPool> SmallWorkerPool;
+	std::unique_ptr<WorkerThreadPool> SyncWorkerPool;
+}  // namespace
+
+WorkerThreadPool&
+GetLargeWorkerPool()
+{
+	{
+		RwLock::SharedLockScope _(PoolLock);
+		if (LargeWorkerPool)
+		{
+			return *LargeWorkerPool;
+		}
+	}
+	RwLock::ExclusiveLockScope _(PoolLock);
+	if (LargeWorkerPool)
+	{
+		return *LargeWorkerPool;
+	}
+	LargeWorkerPool.reset(new WorkerThreadPool(LargeWorkerThreadPoolTreadCount, "LargeThreadPool"));
+	return *LargeWorkerPool;
+}
+
+WorkerThreadPool&
+GetSmallWorkerPool()
+{
+	{
+		RwLock::SharedLockScope _(PoolLock);
+		if (SmallWorkerPool)
+		{
+			return *SmallWorkerPool;
+		}
+	}
+	RwLock::ExclusiveLockScope _(PoolLock);
+	if (SmallWorkerPool)
+	{
+		return *SmallWorkerPool;
+	}
+	SmallWorkerPool.reset(new WorkerThreadPool(SmallWorkerThreadPoolTreadCount, "SmallThreadPool"));
+	return *SmallWorkerPool;
+}
+
+WorkerThreadPool&
+GetSyncWorkerPool()
+{
+	{
+		RwLock::SharedLockScope _(PoolLock);
+		if (SyncWorkerPool)
+		{
+			return *SyncWorkerPool;
+		}
+	}
+	RwLock::ExclusiveLockScope _(PoolLock);
+	if (SyncWorkerPool)
+	{
+		return *SyncWorkerPool;
+	}
+	SyncWorkerPool.reset(new WorkerThreadPool(0, "SyncThreadPool"));
+	return *SyncWorkerPool;
+}
+
+void
+ShutdownWorkerPools()
+{
+	RwLock::ExclusiveLockScope _(PoolLock);
+	LargeWorkerPool.reset();
+	SmallWorkerPool.reset();
+	SyncWorkerPool.reset();
+}
+}  // namespace zen
-- 
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