Java tutorial
//package com.java2s; import java.util.concurrent.CountDownLatch; import java.util.concurrent.Executor; public class Main { public static long time(Executor executor, int concurrency, final Runnable action) throws InterruptedException { final CountDownLatch ready = new CountDownLatch(concurrency); final CountDownLatch start = new CountDownLatch(1); final CountDownLatch done = new CountDownLatch(concurrency); for (int i = 0; i < concurrency; i++) { executor.execute(new Runnable() { @Override public void run() { ready.countDown(); // Tell timer we're ready try { start.await(); // Wait till peers are ready action.run(); } catch (InterruptedException e) { Thread.currentThread().interrupt(); } finally { done.countDown(); // Tell timer we're done } } }); } ready.await(); // Wait for all workers to be ready long startNanos = System.nanoTime(); start.countDown(); // And they're off! done.await(); // Wait for all workers to finish return System.nanoTime() - startNanos; } }