I'm working on a simple benchmark testing out both Mono's ParallelFX against Java on several Linux boxes. The test for .NET runs great on Windows and Linux alike, but I'm having some kind of snag with the Java version...
I can see the specified number of threads starting up, but they run in a strange fashion. It acts like they start up, but they finish very slowly. They continue to start, but take forever to finish. It seems like it should be exceeding the limit of the thread pool, and my CPU usage looks to me like it's only using one or two cores (I've got an i7 processor so something like 8 should try to be used).
Yes, I know I am not being "thread safe" with my integers and probably other stuff too. I don't really care right now. Something larger is an issue here.
C# Version
public class Program
{
static void Main(string[] args)
{
const int numberOfCycles = 1000;
const int numbersPerCycle = 1000000;
Stopwatch swG = Stopwatch.StartNew();
int threadCount = 0;
int completeCount = 0;
Parallel.For(0, numberOfCycles, x =>
{
Console.WriteLine(string.Format("Starting cycle {0}. Thread count at {1}", x, threadCount++));
Random r = new Random();
Stopwatch sw = Stopwatch.StartNew();
List<double> numbers = new List<double>();
for (int i = 0; i < numbersPerCycle; i++)
{
numbers.Add(r.NextDouble() * 1000);
}
numbers.Sort();
double min = numbers.Min();
double max = numbers.Max();
completeCount++;
Console.WriteLine(string.Format("{0} cycles complete: {1:#,##0.0} ms. Min: {2:0.###} Max: {3:0.###}", completeCount, sw.ElapsedMilliseconds, min, max));
threadCount--;
});
Console.WriteLine(string.Format("All {0} cycles complete. Took {1:#,##0.0} ms.", numberOfCycles, swG.ElapsedMilliseconds));
Console.WriteLine("Press any key to continue.");
Console.ReadKey();
}
}
Java Version
P.S. I am lazy and stole the Stopwatch class from here: Is there a stopwatch in Java?
public class JavaMonoTest {
static int threadCount = 0;
static int completeCount = 0;
static String CLRF = "\r\n";
public static void main(String[] args) throws IOException, InterruptedException {
final int numberOfCycles = 1000;
final int numbersPerCycle = 1000000;
final int NUM_CORES = Runtime.getRuntime().availableProcessors();
//Setup the running array
List<Integer> cyclesList = new LinkedList<Integer>();
for(int i = 0; i < numberOfCycles; i++){
cyclesList.add(i);
}
Stopwatch swG = new Stopwatch();
swG.start();
ExecutorService exec = Executors.newFixedThreadPool(NUM_CORES);
try {
for (final Integer x : cyclesList) {
exec.submit(new Runnable() {
@Override
public void run() {
System.out.printf("Starting cycle %s. Thread count at %s %s", x, threadCount++, CLRF);
Random r = new Random();
Stopwatch sw = new Stopwatch();
sw.start();
List<Double> numbers = new LinkedList<Double>();
for (int i = 0; i < numbersPerCycle; i++)
{
numbers.add(r.nextDouble() * 1000);
}
Collections.sort(numbers);
double min = Collections.min(numbers);
double max = Collections.max(numbers);
completeCount++;
System.out.printf("%s cycles complete: %.2f ms. Min: %.2f Max: %.2f %s", completeCount, sw.getElapsedTime(), min, max, CLRF);
threadCount--;
}
});
}
} finally {
exec.shutdown();
}
exec.awaitTermination(1, TimeUnit.DAYS);
System.out.printf("All %s cycles complete. Took %.2f ms. %s", numberOfCycles, swG.getElapsedTime(), CLRF);
System.out.println("Press any key to continue.");
System.in.read();
}
}
Updated C# Version to Match Java Version In Answer
public class Program
{
static void Main(string[] args)
{
const int numberOfCycles = 1000;
const int numbersPerCycle = 1000000;
Stopwatch swG = Stopwatch.StartNew();
int threadCount = 0;
int completeCount = 0;
Parallel.For(0, numberOfCycles, x =>
{
Console.WriteLine(string.Format("Starting cycle {0}. Thread count at {1}", x, Interlocked.Increment(ref threadCount)));
Random r = new Random();
Stopwatch sw = Stopwatch.StartNew();
double[] numbers = new double[numbersPerCycle];
for (int i = 0; i < numbersPerCycle; i++)
{
numbers[i] = r.NextDouble() * 1000;
}
Array.Sort(numbers);
double min = numbers[0];
double max = numbers[numbers.Length - 1];
Interlocked.Increment(ref completeCount);
Console.WriteLine(string.Format("{0} cycles complete: {1:#,##0.0} ms. Min: {2:0.###} Max: {3:0.###}", completeCount, sw.ElapsedMilliseconds, min, max));
Interlocked.Decrement(ref threadCount);
});
Console.WriteLine(string.Format("All {0} cycles complete. Took {1:#,##0.0} ms.", numberOfCycles, swG.ElapsedMilliseconds));
Console.WriteLine("Press any key to continue.");
Console.ReadKey();
}
}
