RFR: 8330802: Desugar switch in Locale::createLocale [v2]

[Naoto Sato]

On Mon, 22 Apr 2024 14:11:41 GMT, Claes Redestad <redestad at openjdk.org> wrote:

>> This switch expression in `Locale::createLocale` is causing a somewhat large startup regression on my local system. Desugaring to if statements seem like the right thing to do while we investigate ways to further reduce overheads in `SwitchBootstraps`.
>> 
>> These numbers are against a baseline which include #18865 and #18845, which already improved the situation:
>> 
>> 
>> Name             Cnt          Base         Error           Test         Error         Unit  Change
>> Perfstartup-Noop  20        40,500 ±       1,942         31,000 ±       2,673        ms/op   1,31x (p = 0,000*)
>>   :.cycles           143254849,000 ± 3398321,355  102205427,650 ± 2192784,853       cycles   0,71x (p = 0,000*)
>>   :.instructions     307138448,850 ± 2095834,550  219415574,800 ±  376992,067 instructions   0,71x (p = 0,000*)
>>   :.taskclock               39,500 ±       1,942         22,500 ±       3,858           ms   0,57x (p = 0,000*)
>>   * = significant
>> 
>> 
>> Comparing to a baseline without those recent improvements the overhead was almost the double: 
>> 
>> Name             Cnt          Base         Error           Test         Error         Unit  Change
>> Perfstartup-Noop  20        50,000 ±       0,000         31,000 ±       2,673        ms/op   1,61x (p = 0,000*)
>>   :.cycles           187047932,000 ± 3330400,381  102205427,650 ± 2192784,853       cycles   0,55x (p = 0,000*)
>>   :.instructions     408219060,350 ± 4031173,140  219415574,800 ±  376992,067 instructions   0,54x (p = 0,000*)
>>   :.taskclock               53,500 ±       4,249         22,500 ±       3,858           ms   0,42x (p = 0,000*)
>>   * = significant
>
> Claes Redestad has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Remove InternalError in favor of CCE

Thanks for the fix, Claes!

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Marked as reviewed by naoto (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/18882#pullrequestreview-2015234211