On Wed, 8 Feb 2023 00:07:14 GMT, Claes Redestad <redes...@openjdk.org> wrote:
>> This patch adds special-cases to `Arrays.copyOf` and `Arrays.copyOfRange` to
>> clone arrays when `newLength` or range inputs span the input array. This
>> helps eliminate range checks and has been verified to help various String
>> operations. Example:
>>
>> Baseline
>>
>> Benchmark (size) Mode Cnt
>> Score Error Units
>> StringConstructor.newStringFromArray 7 avgt 15
>> 16.817 ± 0.369 ns/op
>> StringConstructor.newStringFromArrayWithCharset 7 avgt 15
>> 16.866 ± 0.449 ns/op
>> StringConstructor.newStringFromArrayWithCharsetName 7 avgt 15
>> 22.198 ± 0.396 ns/op
>>
>> Patch:
>>
>> Benchmark (size) Mode Cnt
>> Score Error Units
>> StringConstructor.newStringFromArray 7 avgt 15
>> 14.666 ± 0.336 ns/op
>> StringConstructor.newStringFromArrayWithCharset 7 avgt 15
>> 14.582 ± 0.288 ns/op
>> StringConstructor.newStringFromArrayWithCharsetName 7 avgt 15
>> 20.339 ± 0.328 ns/op
>
> Claes Redestad has updated the pull request incrementally with one additional
> commit since the last revision:
>
> Minimize, force inline, generalize
test/micro/org/openjdk/bench/java/lang/StringConstructor.java line 40:
> 38:
> 39: @Param({"0", "7", "64"})
> 40: public int size;
I suggest to add the param `offset` for future experiment: together with
`perfasm` it helps to check how different stubs are used and emulate the
different branches of the optimized code
-------------
PR: https://git.openjdk.org/jdk/pull/12453
