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TailRecursionBenchmark.java
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TailRecursionBenchmark.java
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/*
* JVM Performance Benchmarks
*
* Copyright (C) 2019 - 2024 Ionut Balosin
*
* 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 com.ionutbalosin.jvm.performance.benchmarks.compiler;
import java.util.concurrent.TimeUnit;
import org.openjdk.jmh.annotations.Benchmark;
import org.openjdk.jmh.annotations.BenchmarkMode;
import org.openjdk.jmh.annotations.Fork;
import org.openjdk.jmh.annotations.Measurement;
import org.openjdk.jmh.annotations.Mode;
import org.openjdk.jmh.annotations.OutputTimeUnit;
import org.openjdk.jmh.annotations.Param;
import org.openjdk.jmh.annotations.Scope;
import org.openjdk.jmh.annotations.Setup;
import org.openjdk.jmh.annotations.State;
import org.openjdk.jmh.annotations.Warmup;
/*
* A tail-recursive function is a function where the last operation before the function returns is an invocation to the function itself.
* Tail-recursive optimization avoids allocating a new stack frame by re-writing the method into a completely iterative fashion.
*/
@BenchmarkMode(Mode.AverageTime)
@OutputTimeUnit(TimeUnit.MICROSECONDS)
@Warmup(iterations = 5, time = 10, timeUnit = TimeUnit.SECONDS)
@Measurement(iterations = 5, time = 10, timeUnit = TimeUnit.SECONDS)
@Fork(
value = 5,
jvmArgsAppend = {"-Xss64M"})
@State(Scope.Benchmark)
public class TailRecursionBenchmark {
// $ java -jar */*/benchmarks.jar ".*TailRecursionBenchmark.*"
@Param({"262144"})
int n;
private final int size = 1024;
private int[] A;
@Setup
public void setup() {
A = new int[size];
for (int i = 0; i < size; i++) {
A[i] = i;
}
}
@Benchmark
public long tail_recursive() {
return recursive(n, 0);
}
@Benchmark
public long iterative() {
return iterative(n, 0);
}
private long recursive(int n, long sum) {
if (n == 0) {
return sum;
} else {
return recursive(n - 1, sum + A[n % size]);
}
}
private long iterative(int n, long sum) {
while (true) {
if (n == 0) {
return sum;
} else {
sum += A[n % size];
n--;
}
}
}
}