From a68625c8acb763ce775bd5648970099a2661e3b5 Mon Sep 17 00:00:00 2001
From: Souryo <mesenemu@gmail.com>
Date: Tue, 26 Jan 2016 17:21:33 -0500
Subject: [PATCH] Locks: Used thread_local to remove calls to
 GetCurrentThreadId (faster)

---
 Utilities/SimpleLock.cpp | 24 +++++++-----------------
 Utilities/SimpleLock.h   |  7 ++++---
 2 files changed, 11 insertions(+), 20 deletions(-)

diff --git a/Utilities/SimpleLock.cpp b/Utilities/SimpleLock.cpp
index e263857a..5129986a 100644
--- a/Utilities/SimpleLock.cpp
+++ b/Utilities/SimpleLock.cpp
@@ -1,30 +1,20 @@
 #include "stdafx.h"
 #include <assert.h>
 #include "SimpleLock.h"
-#ifdef WIN32
-	#include <Windows.h>
-#endif
+
+thread_local std::thread::id SimpleLock::_threadID = std::this_thread::get_id();
 
 SimpleLock::SimpleLock()
 {
 	_lock.clear();
 	_lockCount = 0;
-	_holderThreadID = ~0;
+	_holderThreadID = std::thread::id();
 }
 
 SimpleLock::~SimpleLock()
 {
 }
 
-uint32_t SimpleLock::GetThreadId()
-{
-#ifdef WIN32
-	return GetCurrentThreadId();
-#elif
-	return std::thread::id;
-#endif
-}
-
 LockHandler SimpleLock::AcquireSafe()
 {
 	return LockHandler(this);
@@ -32,9 +22,9 @@ LockHandler SimpleLock::AcquireSafe()
 
 void SimpleLock::Acquire()
 {
-	if(_lockCount == 0 || _holderThreadID != GetThreadId()) {
+	if(_lockCount == 0 || _holderThreadID != _threadID) {
 		while(_lock.test_and_set());
-		_holderThreadID = GetThreadId();
+		_holderThreadID = _threadID;
 		_lockCount = 1;
 	} else {
 		//Same thread can acquire the same lock multiple times
@@ -60,10 +50,10 @@ void SimpleLock::WaitForRelease()
 
 void SimpleLock::Release()
 {
-	if(_lockCount > 0 && _holderThreadID == GetThreadId()) {
+	if(_lockCount > 0 && _holderThreadID == _threadID) {
 		_lockCount--;
 		if(_lockCount == 0) {
-			_holderThreadID = ~0;
+			_holderThreadID = std::thread::id();
 			_lock.clear();
 		}
 	} else {
diff --git a/Utilities/SimpleLock.h b/Utilities/SimpleLock.h
index 09d6cd1c..630a3ab6 100644
--- a/Utilities/SimpleLock.h
+++ b/Utilities/SimpleLock.h
@@ -1,5 +1,6 @@
 #pragma once 
 #include "stdafx.h"
+#include <thread>
 
 class SimpleLock;
 
@@ -15,12 +16,12 @@ public:
 class SimpleLock
 {
 private:
-	uint32_t _holderThreadID;
+	thread_local static std::thread::id _threadID;
+
+	std::thread::id _holderThreadID;
 	uint32_t _lockCount;
 	atomic_flag _lock;
 
-	uint32_t GetThreadId();
-
 public:
 	SimpleLock();
 	~SimpleLock();