Traversing an array of value types seen as an array of Object is slow
forax at univ-mlv.fr
Wed Jun 27 18:56:39 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.
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