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// Copyright Vespa.ai. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.concurrent;
import java.util.ArrayList;
import java.util.List;
/**
* @author baldersheim
* @since 5.2
*/
public class RcuHashMapBenchmark {
static class Actor implements Runnable {
private final CopyOnWriteHashMap<Long, Long> m;
private long mSum = 0;
private long mMissRate = 0;
Actor(CopyOnWriteHashMap<Long, Long> m) {
this.m = m;
}
@Override
public void run() {
final int NUM_UPDATES=100;
final long NUM_LOOKUPS=10000000;
final List<Long> upd = new ArrayList<Long>(NUM_UPDATES);
upd.add(0l);
long missRate = 0;
long sum = 0;
for (long i=0; i < NUM_LOOKUPS; i++) {
long t = i%upd.size();
Long v = m.get(upd.get((int)t));
if (v == null) {
missRate++;
m.put(upd.get((int)t), i);
sum += i;
} else {
sum += v;
}
if (i%(NUM_LOOKUPS/NUM_UPDATES) == 0) {
upd.add((long)upd.size());
}
}
synchronized (this) {
mSum = sum;
mMissRate = missRate;
}
}
long getSum() { synchronized (this) { return mSum; } }
long getMissRate() { synchronized (this) { return mMissRate;} }
}
RcuHashMapBenchmark(int numThreads) {
CopyOnWriteHashMap<Long, Long> m = new CopyOnWriteHashMap<Long, Long>();
Thread[] threads = new Thread[numThreads];
Actor [] actors = new Actor[threads.length];
for (int i = 0; i < threads.length; ++i) {
Actor a = new Actor(m);
actors[i] = a;
threads[i] = new Thread(a);
}
runAll(threads);
long missRate=0;
long sum=0;
for (Actor a : actors) {
missRate += a.getMissRate();
sum += a.getSum();
System.out.println("Missrate: " + a.getMissRate() + " sum = " + a.getSum());
}
System.out.println("Total Missrate: " + missRate + " sum = " + sum);
}
private void runAll(Thread[] threads) {
for (Thread t : threads) {
t.start();
}
for (Thread t : threads) {
try {
t.join();
} catch (InterruptedException e) {
// nop
}
}
}
public static void main(String[] args) {
long start, end;
start = System.currentTimeMillis();
new RcuHashMapBenchmark(1);
end = System.currentTimeMillis();
System.out.println("Elapsed during warmup: " + (end - start) + " ms.");
for (int i=0; i < 16; i++) {
start = System.currentTimeMillis();
new RcuHashMapBenchmark(i+1);
end = System.currentTimeMillis();
System.out.println("Elapsed during " + (i+1) + " threads: " + (end - start) + " ms.");
}
}
}
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