Chronicle-Map/src/test/java/net/openhft/chronicle/map/example/DistributedSequenceMain.java

/*
 * Copyright 2014 Higher Frequency Trading
 *
 * http://www.higherfrequencytrading.com
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package net.openhft.chronicle.map.example;

import net.openhft.chronicle.map.ChronicleMap;
import net.openhft.chronicle.map.ChronicleMapBuilder;
import net.openhft.lang.model.DataValueClasses;
import net.openhft.lang.values.LongValue;

import java.io.File;
import java.io.IOException;
import java.util.Arrays;

public class DistributedSequenceMain {

    public static void main(String... ignored) throws IOException {
        File file = File.createTempFile("sequence-numbers", ".dat");
        try (ChronicleMap<String, LongValue> map =
                     ChronicleMapBuilder.of(String.class, LongValue.class)
                             .entries(128)
                             .actualSegments(1)
                             .createPersistedTo(file)) {
            // throughput test.
            for (int t = 0; t < 5; t++) {
                LongValue value = DataValueClasses.newDirectReference(LongValue.class);
                map.acquireUsing("sequence-" + t, value);

                long start = System.nanoTime();
                int runs = 1000000;
                for (int i = 0; i < runs; i++) {
                    long nextId = value.addAtomicValue(1);
                }
                double rate = (double) (System.nanoTime() - start) / runs;
                System.out.printf("Uncontended increment took an average of %.1f ns.%n", rate);
            }

            // latency test.
            LongValue value = DataValueClasses.newDirectReference(LongValue.class);
            map.acquireUsing("sequence-X", value);

            int runs = 1000000000, count = 0, wcount = 0;
            long[] worst = new long[200000];
            long start = System.nanoTime();
            for (; count < runs; count++) {
                long nextId = value.addAtomicValue(1);
                long next = System.nanoTime();
                long time = next - start;
                if (time > 100) {
                    worst[wcount++] = time;
                    if (wcount >= worst.length)
                        break;
                    next = System.nanoTime();
                }
                start = next;
            }
            Arrays.sort(worst);
            System.out.printf("Worst 1 in 10K, 1 in 100K, 1 in 1000K, worst is %,d / %,d / %,d / %,d %n",
                    worst[wcount - count / 10000],
                    worst[wcount - count / 100000],
                    worst[wcount - count / 1000000],
                    worst[wcount - 1]
            );
        }
    }
}