Merge pull request #271 from delroth/threading-stuff

Threading improvements: add Common::Flag and improve Common::Event

1 files changed, 91 insertions, 0 deletions

diff --git a/Source/UnitTests/Common/FlagTest.cpp b/Source/UnitTests/Common/FlagTest.cpp
new file mode 100644
index 0000000000..a3a0c3d929
--- /dev/null
+++ b/Source/UnitTests/Common/FlagTest.cpp
@@ -0,0 +1,91 @@
+// Copyright 2014 Dolphin Emulator Project
+// Licensed under GPLv2
+// Refer to the license.txt file included.
+
+#include <array>
+#include <gtest/gtest.h>
+#include <thread>
+
+#include "Common/Flag.h"
+
+using Common::Flag;
+
+TEST(Flag, Simple)
+{
+	Flag f;
+	EXPECT_FALSE(f.IsSet());
+
+	f.Set();
+	EXPECT_TRUE(f.IsSet());
+
+	f.Clear();
+	EXPECT_FALSE(f.IsSet());
+
+	f.Set(false);
+	EXPECT_FALSE(f.IsSet());
+
+	EXPECT_TRUE(f.TestAndSet());
+	EXPECT_TRUE(f.TestAndClear());
+
+	Flag f2(true);
+	EXPECT_TRUE(f2.IsSet());
+}
+
+TEST(Flag, MultiThreaded)
+{
+	Flag f;
+	int count = 0;
+	const int ITERATIONS_COUNT = 100000;
+
+	auto setter = [&f]() {
+		for (int i = 0; i < ITERATIONS_COUNT; ++i)
+		{
+			while (f.IsSet());
+			f.Set();
+		}
+	};
+
+	auto clearer = [&f, &count]() {
+		for (int i = 0; i < ITERATIONS_COUNT; ++i)
+		{
+			while (!f.IsSet());
+			count++;
+			f.Clear();
+		}
+	};
+
+	std::thread setter_thread(setter);
+	std::thread clearer_thread(clearer);
+
+	setter_thread.join();
+	clearer_thread.join();
+
+	EXPECT_EQ(ITERATIONS_COUNT, count);
+}
+
+TEST(Flag, SpinLock)
+{
+	// Uses a flag to implement basic spinlocking using TestAndSet.
+	Flag f;
+	int count = 0;
+	const int ITERATIONS_COUNT = 5000;
+	const int THREADS_COUNT = 50;
+
+	auto adder_func = [&]() {
+		for (int i = 0; i < ITERATIONS_COUNT; ++i)
+		{
+			// Acquire the spinlock.
+			while (!f.TestAndSet());
+			count++;
+			f.Clear();
+		}
+	};
+
+	std::array<std::thread, THREADS_COUNT> threads;
+	for (auto& th : threads)
+		th = std::thread(adder_func);
+	for (auto& th : threads)
+		th.join();
+
+	EXPECT_EQ(ITERATIONS_COUNT * THREADS_COUNT, count);
+}