// take activating a timeout
public T Take(int timeout)
{
if (!filledSlots.Wait(timeout))
{
return(null); // time out
}
T item;
lock (room)
{
item = room[takeIdx++ % queueSize];
}
freeSlots.Release();
return(item);
}
// test semaphore fairness asynchronous
private static bool TestSemaphoreFairnessAsync()
{
const int SETUP_TIME = 50;
const int THREADS = 50;
const int MIN_TIMEOUT = 5;
const int MAX_TIMEOUT = 20;
Thread[] tthrs = new Thread[THREADS];
int[] privateCounters = new int[THREADS];
ManualResetEventSlim startEvent = new ManualResetEventSlim(false);
var sem = new SemaphoreAsync(THREADS, THREADS);
int totalTimeouts = 0;
bool exit = false;
for (int i = 0; i < THREADS; i++)
{
int tid = i;
tthrs[i] = new Thread(() => {
Random random = new Random(tid);
// Wait until start event is set
startEvent.Wait();
do
{
do
{
if (sem.WaitAsyncEx(random.Next(MIN_TIMEOUT, MAX_TIMEOUT),
CancellationToken.None).Result)
{
break;
}
Interlocked.Increment(ref totalTimeouts);
} while (true);
Thread.Yield();
sem.Release();
if ((++privateCounters[tid] % 100) == 0)
{
Console.Write("[#{0}]", tid);
}
} while (!Volatile.Read(ref exit));
});
tthrs[i].Start();
}
// Wait until all test threads have been started and then set the
// start event.
Thread.Sleep(SETUP_TIME);
startEvent.Set();
do
{
Thread.Sleep(50);
} while (!Console.KeyAvailable);
Console.Read();
Volatile.Write(ref exit, true);
// Wait until all threads have been terminated.
for (int i = 0; i < THREADS; i++)
{
tthrs[i].Join();
}
// Show results
int total = 0;
Console.WriteLine("\nPrivate counters:");
for (int i = 0; i < THREADS; i++)
{
if (i != 0 && (i % 5) == 0)
{
Console.WriteLine();
}
Console.Write("[#{0:D2}:{1,4}]", i, privateCounters[i]);
total += privateCounters[i];
}
Console.WriteLine("\n-- total acquisitions/releases: {0}, timeouts: {1}", total, totalTimeouts);
return(true);
}