61 lines
2.0 KiB
Java
61 lines
2.0 KiB
Java
package org.openjdk.bench.java.math;
|
|
|
|
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.State;
|
|
import org.openjdk.jmh.annotations.Warmup;
|
|
|
|
import java.math.BigInteger;
|
|
import java.util.concurrent.TimeUnit;
|
|
import java.util.function.BinaryOperator;
|
|
|
|
/**
|
|
* Benchmark for checking performance difference between
|
|
* sequential and parallel multiply methods in BigInteger,
|
|
* using a large Fibonacci calculation of up to n = 100 million.
|
|
*
|
|
* @author Heinz Kabutz, heinz@javaspecialists.eu
|
|
*/
|
|
@BenchmarkMode(Mode.SingleShotTime)
|
|
@OutputTimeUnit(TimeUnit.MILLISECONDS)
|
|
@Fork(value = 2)
|
|
@Warmup(iterations = 2)
|
|
@Measurement(iterations = 2) // only 2 iterations because each one takes very long
|
|
@State(Scope.Thread)
|
|
public class BigIntegerParallelMultiply {
|
|
private static BigInteger fibonacci(int n, BinaryOperator<BigInteger> multiplyOperator) {
|
|
if (n == 0) return BigInteger.ZERO;
|
|
if (n == 1) return BigInteger.ONE;
|
|
|
|
int half = (n + 1) / 2;
|
|
BigInteger f0 = fibonacci(half - 1, multiplyOperator);
|
|
BigInteger f1 = fibonacci(half, multiplyOperator);
|
|
if (n % 2 == 1) {
|
|
BigInteger b0 = multiplyOperator.apply(f0, f0);
|
|
BigInteger b1 = multiplyOperator.apply(f1, f1);
|
|
return b0.add(b1);
|
|
} else {
|
|
BigInteger b0 = f0.shiftLeft(1).add(f1);
|
|
return multiplyOperator.apply(b0, f1);
|
|
}
|
|
}
|
|
|
|
@Param({"1000000", "10000000", "100000000"})
|
|
private int n;
|
|
|
|
@Benchmark
|
|
public void multiply() {
|
|
fibonacci(n, BigInteger::multiply);
|
|
}
|
|
|
|
@Benchmark
|
|
public void parallelMultiply() {
|
|
fibonacci(n, BigInteger::parallelMultiply);
|
|
}
|
|
} |