private static void InitializationAndWarmup()
{
Console.WriteLine("Initialization and Warmup...");
double warmupSum = 0.0;
IDummy dummy = DummyFactory.Get();
fixed(int *a = new int[1])
//int[] a = new int[4 * 2 * 2];
{
Arr arr = new Arr()
{
a = a
};
for (int i = 1; i < 10; i++)
{
Run(arr, 0, 4, 2, 2, 10, 0, dummy);
}
}
if (warmupSum == 42)
{
Console.WriteLine("warmupSum=" + warmupSum);
}
Process.GetCurrentProcess().PriorityClass = ProcessPriorityClass.RealTime;
GC.Collect();
GC.WaitForPendingFinalizers();
}
private static double RunVectorTriad(long vectorLength, long repetitions, int numberOfThreads)
{
GC.Collect();
GC.WaitForPendingFinalizers();
TriadData[] data = new TriadData[numberOfThreads];
for (int i = 0; i < numberOfThreads; i++)
{
data[i] = new TriadData(vectorLength);
}
IDummy dummy = DummyFactory.Get();
Task[] tasks = new Task[numberOfThreads];
for (int i = 0; i < numberOfThreads; i++)
{
int threadIndex = i;
tasks[i] = new Task(() => RunVectorTriad(data[threadIndex], vectorLength, repetitions, dummy));
}
Stopwatch stopwatch = Stopwatch.StartNew();
for (int i = 0; i < numberOfThreads; i++)
{
tasks[i].Start();
}
Task.WaitAll(tasks.Take(numberOfThreads).ToArray());
stopwatch.Stop();
return((double)stopwatch.ElapsedMilliseconds / repetitions);
}
static void Main(string[] args)
{
Chart chart = new Chart("Runtime", "Associativity", "Runtime [s]", false);
InitializationAndWarmup();
//int cacheSize = (1 << 23) / 4; //Use to provoke cache thrashing. Value must be the L3 cache-size in integer (i.e. cache size in byte divided by sizeof(int)).
int cacheSize = 2999999; //Use to avoid cache thrashing. May be larger than the L3 cache-size but should be prime.
int cacheLineLength = 64 / 4;
int numberOfThreads = 8;
long repetitions = 1 << 2;
int cnt = 0;
IDummy dummy = DummyFactory.Get();
for (int associativity = 1; associativity <= 16; associativity++)
{
int n = cacheSize * associativity * numberOfThreads;
int[] arr = new int[n];
for (int i = 0; i < n; i++)
arr[i] = cnt++;
fixed(int *a = arr)
{
Arr array = new Arr()
{
a = a
};
Thread[] threads = new Thread[numberOfThreads];
for (int i = 0; i < numberOfThreads; i++)
{
int start = associativity * cacheSize * i;
int coreIndex = i;
threads[i] = new Thread(
() => Run(array, start, cacheSize, cacheLineLength, associativity, repetitions, coreIndex, dummy));
}
Stopwatch stopwatch = Stopwatch.StartNew();
foreach (Thread thread in threads)
{
thread.Start();
}
for (int i = 0; i < numberOfThreads; i++)
{
threads[i].Join();
}
stopwatch.Stop();
string sumIndicator = totalSum == 42 ? "42" : "";
Console.WriteLine($"associativity={associativity} elapsed={stopwatch.Elapsed} {sumIndicator}");
chart.Add($"{numberOfThreads} threads", associativity, stopwatch.ElapsedMilliseconds);
}
}
chart.Save(typeof(CacheThrashing));
chart.Show();
Console.WriteLine("Finished...");
Console.ReadKey();
}