RFR: Samples/jmh sample 39 memory access [v2]

[Michael Mirwaldt]

On Mon, 17 Oct 2022 07:56:42 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

>> Michael Mirwaldt has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   improved by proposals from first review
>
> Quick review...

Thanks so far for your suggestions, @shipilev.

> jmh-samples/src/main/java/org/openjdk/jmh/samples/JMHSample_39_MemoryAccess.java line 64:
> 
>> 62:      *
>> 63:      * Benchmark                               Mode  Cnt        Score      Error  Units
>> 64:      * JMHSample_39_MemoryAccess.sumArray      avgt   25        5.117 ±    0.039  ns/op
> 
> 5 ns to sum 1M elements seems way too low.

I increased N from 1_000_000 to 100_000_000, changed the output time unit from nano to millis and updated the benchmarks result shown in the comment.

> jmh-samples/src/main/java/org/openjdk/jmh/samples/JMHSample_39_MemoryAccess.java line 96:
> 
>> 94:         long sum = 0;
>> 95:         for (int i = 0; i < N; i++) {
>> 96:             sum = intList.get(i);
> 
> This needs to be `+=`.

Done

-------------

PR: https://git.openjdk.org/jmh/pull/85