Traversing an array of value types seen as an array of Object is slow
rwestrel at redhat.com
Thu Jun 28 07:31:24 UTC 2018
> I maybe wrong with the conclusion but this benchmark  show that there is something fishy.
> Benchmark Mode Cnt Score Error Units
> ReifiedListBenchMark.arraylist_integer_get avgt 9 0.068 ± 0.001 ms/op
> ReifiedListBenchMark.arraylist_integer_iterator avgt 9 0.069 ± 0.001 ms/op
> ReifiedListBenchMark.reifiedlist_intbox_cursor avgt 9 516.526 ± 11.903 ms/op
> ReifiedListBenchMark.reifiedlist_intbox_get avgt 9 523.149 ± 9.194 ms/op
> ReifiedListBenchMark.reifiedlist_intbox_iterator avgt 9 514.091 ± 18.357 ms/op
> A reified list uses an array created by reflection and seen as an Object.
> The creation and the population of the array is done out-of-the-band and not benchmarked,
> the benchmark only test several ways to access to the array in a loop.
> It seems that the JIT never try to optimize the loop for whatever
> reason so the loop is done by the interpreter and only the access to
> the array cell is JITed.
Thanks for reporting the issue. I'm taking a look.
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