TEST(Flag, MultiThreaded)
{
Flag f;
int count = 0;
const int ITERATIONS_COUNT = 100000;
auto setter = [&]() {
for (int i = 0; i < ITERATIONS_COUNT; ++i)
{
while (f.IsSet());
f.Set();
}
};
auto clearer = [&]() {
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);
}
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());
}
