test/loops/ContextSwitchTest.java

import java.util.concurrent.*;
import java.util.concurrent.locks.*;
import java.util.concurrent.atomic.*;
import java.util.*;

public final class ContextSwitchTest {
    final static int iters = 1000000;
    static AtomicReference turn = new AtomicReference();
    public static void main(String[] args) throws Exception {
        MyThread a = new MyThread();
        MyThread b = new MyThread();
        a.other = b;
        b.other = a;
        turn.set(a);
        long startTime = System.nanoTime();
        a.start();
        b.start();
        a.join();
        b.join();
        long endTime = System.nanoTime();
        int np = a.nparks + b.nparks;
        System.out.println((endTime - startTime) / np);
    }

    private static int nextRandom(int x) { 
        int t = (x % 127773) * 16807 - (x / 127773) * 2836;
        return (t > 0)? t : t + 0x7fffffff;
    }

    static final class MyThread extends Thread {
        volatile Thread other;
        volatile int nparks;
        volatile int result;

        public void run() {
            int x = 17;
            int p = 0;
            for (int i = 0; i < iters; ++i) {
                while (!turn.compareAndSet(other, this)) {
                    LockSupport.park();
                    ++p;
                }
                x = nextRandom(x);
                LockSupport.unpark(other);
            }
            LockSupport.unpark(other);
            nparks = p;
            result = x;
            System.out.println("parks: " + p);
            
        }
    }
}


Revision:	1.1
Committed:	Mon May 2 19:19:38 2005 UTC (19 years ago) by dl
Branch:	MAIN
Log Message:	Put misc performance tests into CVS
#	User	Rev	Content
1	dl	1.1	import java.util.concurrent.*;
2			import java.util.concurrent.locks.*;
3			import java.util.concurrent.atomic.*;
4			import java.util.*;
5
6			public final class ContextSwitchTest {
7			final static int iters = 1000000;
8			static AtomicReference turn = new AtomicReference();
9			public static void main(String[] args) throws Exception {
10			MyThread a = new MyThread();
11			MyThread b = new MyThread();
12			a.other = b;
13			b.other = a;
14			turn.set(a);
15			long startTime = System.nanoTime();
16			a.start();
17			b.start();
18			a.join();
19			b.join();
20			long endTime = System.nanoTime();
21			int np = a.nparks + b.nparks;
22			System.out.println((endTime - startTime) / np);
23			}
24
25			private static int nextRandom(int x) {
26			int t = (x % 127773) * 16807 - (x / 127773) * 2836;
27			return (t > 0)? t : t + 0x7fffffff;
28			}
29
30			static final class MyThread extends Thread {
31			volatile Thread other;
32			volatile int nparks;
33			volatile int result;
34
35			public void run() {
36			int x = 17;
37			int p = 0;
38			for (int i = 0; i < iters; ++i) {
39			while (!turn.compareAndSet(other, this)) {
40			LockSupport.park();
41			++p;
42			}
43			x = nextRandom(x);
44			LockSupport.unpark(other);
45			}
46			LockSupport.unpark(other);
47			nparks = p;
48			result = x;
49			System.out.println("parks: " + p);
50
51			}
52			}
53			}
54
55