RFR: 8275821: Optimize random number generators developed in JDK-8248862 using Math.unsignedMultiplyHigh() [v5]

[Paul Sandoz]

On Fri, 3 Dec 2021 00:17:04 GMT, Vamsi Parasa <duke at openjdk.java.net> wrote:

>> This change optimizes random number generators using Math.unsignedMultiplyHigh()
>
> Vamsi Parasa has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Update the JMH micro to take RNG parameters for elegant implementation

Very nice, much neater, just a few more minor comments.

test/micro/org/openjdk/bench/java/util/RandomGeneratorNext.java line 47:

> 45: public class RandomGeneratorNext {
> 46: 
> 47:     public RandomGenerator randomGenerator;

Suggestion:

    RandomGenerator randomGenerator;

test/micro/org/openjdk/bench/java/util/RandomGeneratorNext.java line 52:

> 50:     String randomGeneratorName;
> 51: 
> 52:     public static long[] buffer;

Suggestion:

    long[] buffer;

test/micro/org/openjdk/bench/java/util/RandomGeneratorNext.java line 69:

> 67: 
> 68:     @Benchmark
> 69:     @Fork(1)

Why is `@Fork` need here?

test/micro/org/openjdk/bench/java/util/RandomGeneratorNext.java line 70:

> 68:     @Benchmark
> 69:     @Fork(1)
> 70:     public void testFillBufferWithNextLong() {

Return `buffer` after the loop completes, just in case the JIT decides it is otherwise dead code

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PR: https://git.openjdk.java.net/jdk/pull/6206