| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You 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 org.apache.commons.rng.examples.jmh.distribution; |
| |
| import org.apache.commons.rng.RestorableUniformRandomProvider; |
| import org.apache.commons.rng.UniformRandomProvider; |
| import org.apache.commons.rng.sampling.distribution.DiscreteUniformSampler; |
| import org.apache.commons.rng.sampling.distribution.SharedStateDiscreteSampler; |
| import org.apache.commons.rng.simple.RandomSource; |
| import org.openjdk.jmh.annotations.Benchmark; |
| import org.openjdk.jmh.annotations.BenchmarkMode; |
| import org.openjdk.jmh.annotations.Mode; |
| import org.openjdk.jmh.annotations.Warmup; |
| import org.openjdk.jmh.infra.Blackhole; |
| import org.openjdk.jmh.annotations.Measurement; |
| import org.openjdk.jmh.annotations.State; |
| import org.openjdk.jmh.annotations.Fork; |
| import org.openjdk.jmh.annotations.Scope; |
| import org.openjdk.jmh.annotations.Setup; |
| import org.openjdk.jmh.annotations.OutputTimeUnit; |
| import org.openjdk.jmh.annotations.Param; |
| |
| import java.util.concurrent.TimeUnit; |
| |
| /** |
| * Executes benchmark to compare the speed of generation of integer numbers in a positive range |
| * using the {@link DiscreteUniformSampler} or {@link UniformRandomProvider#nextInt(int)}. |
| */ |
| @BenchmarkMode(Mode.AverageTime) |
| @OutputTimeUnit(TimeUnit.NANOSECONDS) |
| @Warmup(iterations = 5, time = 1, timeUnit = TimeUnit.SECONDS) |
| @Measurement(iterations = 5, time = 1, timeUnit = TimeUnit.SECONDS) |
| @State(Scope.Benchmark) |
| @Fork(value = 1, jvmArgs = { "-server", "-Xms128M", "-Xmx128M" }) |
| public class DiscreteUniformSamplerGenerationPerformance { |
| /** The number of samples. */ |
| @Param({ |
| "1", |
| "2", |
| "4", |
| "8", |
| "16", |
| "1000000", |
| }) |
| private int samples; |
| |
| /** |
| * The benchmark state (retrieve the various "RandomSource"s). |
| */ |
| @State(Scope.Benchmark) |
| public static class Sources { |
| /** |
| * RNG providers. |
| * |
| * <p>Use different speeds.</p> |
| * |
| * @see <a href="https://commons.apache.org/proper/commons-rng/userguide/rng.html"> |
| * Commons RNG user guide</a> |
| */ |
| @Param({"SPLIT_MIX_64", |
| // Comment in for slower generators |
| //"MWC_256", "KISS", "WELL_1024_A", |
| //"WELL_44497_B" |
| }) |
| private String randomSourceName; |
| |
| /** RNG. */ |
| private RestorableUniformRandomProvider generator; |
| |
| /** |
| * @return the RNG. |
| */ |
| public UniformRandomProvider getGenerator() { |
| return generator; |
| } |
| |
| /** Instantiates generator. */ |
| @Setup |
| public void setup() { |
| final RandomSource randomSource = RandomSource.valueOf(randomSourceName); |
| generator = RandomSource.create(randomSource); |
| } |
| } |
| |
| /** |
| * The upper range for the {@code int} generation. |
| */ |
| @State(Scope.Benchmark) |
| public static class IntRange { |
| /** |
| * The upper range for the {@code int} generation. |
| * |
| * <p>Note that the while loop uses a rejection algorithm. From the Javadoc for java.util.Random:</p> |
| * |
| * <pre> |
| * "The probability of a value being rejected depends on n. The |
| * worst case is n=2^30+1, for which the probability of a reject is 1/2, |
| * and the expected number of iterations before the loop terminates is 2." |
| * </pre> |
| */ |
| @Param({ |
| "256", // Even: 1 << 8 |
| "257", // Prime number |
| "1073741825", // Worst case: (1 << 30) + 1 |
| }) |
| private int upperBound; |
| |
| /** |
| * Gets the upper bound. |
| * |
| * @return the upper bound |
| */ |
| public int getUpperBound() { |
| return upperBound; |
| } |
| } |
| |
| // Benchmark methods. |
| // Avoid consuming the generated values inside the loop. Use a sum and |
| // consume at the end. This reduces the run-time as the BlackHole has |
| // a relatively high overhead compared with number generation. |
| // Subtracting the baseline from the other timings provides a measure |
| // of the extra work done by the algorithm to produce unbiased samples in a range. |
| |
| /** |
| * @param bh the data sink |
| * @param source the source |
| */ |
| @Benchmark |
| public void nextIntBaseline(Blackhole bh, Sources source) { |
| int sum = 0; |
| for (int i = 0; i < samples; i++) { |
| sum += source.getGenerator().nextInt(); |
| } |
| bh.consume(sum); |
| } |
| |
| /** |
| * @param bh the data sink |
| * @param source the source |
| * @param range the range |
| */ |
| @Benchmark |
| public void nextIntRange(Blackhole bh, Sources source, IntRange range) { |
| final int n = range.getUpperBound(); |
| int sum = 0; |
| for (int i = 0; i < samples; i++) { |
| sum += source.getGenerator().nextInt(n); |
| } |
| bh.consume(sum); |
| } |
| |
| /** |
| * @param bh the data sink |
| * @param source the source |
| * @param range the range |
| */ |
| @Benchmark |
| public void nextDiscreteUniformSampler(Blackhole bh, Sources source, IntRange range) { |
| // Note: The sampler upper bound is inclusive. |
| final SharedStateDiscreteSampler sampler = DiscreteUniformSampler.of( |
| source.getGenerator(), 0, range.getUpperBound() - 1); |
| int sum = 0; |
| for (int i = 0; i < samples; i++) { |
| sum += sampler.sample(); |
| } |
| bh.consume(sum); |
| } |
| } |