RFR: 8356993: ArrayDeque should use Arrays.fill() instead of for() loops [v2]

[Archie Cobbs]

On Thu, 15 May 2025 18:33:22 GMT, Raffaello Giulietti <rgiulietti at openjdk.org> wrote:

> Here are many [exmaples](https://github.com/openjdk/jmh/tree/master/jmh-samples/src/main/java/org/openjdk/jmh/samples) on how to correctly use JMH.
> 
> A [blackhole](https://github.com/openjdk/jmh/blob/master/jmh-samples/src/main/java/org/openjdk/jmh/samples/JMHSample_09_Blackholes.java) prevents the compiler to optimize away your code.

Thanks for the tip. FWIW after doing that the numbers came out about the same - which is not surprising given that `Arrays.fill()` is just the same `for()` loop...


#2 - After adding Blackhole

jdk-25+22-94-g0318e49500e (master):
Benchmark                                       Mode  Cnt   Score   Error  Units
ArrayDeque.ClearBenchmarkTestJMH.fillAndClear  thrpt   50  35.663 ± 0.163  ops/s

jdk-25+22-97-g9f0c5fe1f90 (JDK-8356993):
Benchmark                                       Mode  Cnt   Score   Error  Units
ArrayDeque.ClearBenchmarkTestJMH.fillAndClear  thrpt   50  35.112 ± 0.501  ops/s

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PR Review Comment: https://git.openjdk.org/jdk/pull/25237#discussion_r2091954179