On Mon, 19 Aug 2024 23:14:06 GMT, Shaojin Wen <d...@openjdk.org> wrote:
>> The current implementation of ofDescriptor puts return type and parameter >> types together in an ArrayList, and then splits them into return type and >> array of parameter types. This ArrayList creation is unnecessary, >> considering most descriptors only have few parameter types. >> >> By splitting return type and parameter types separately and scanning the >> descriptor first to get the number of parameters, we can just allocate an >> exact, trusted array for the resulting MethodTypeDesc without copy. > > Shaojin Wen has updated the pull request incrementally with one additional > commit since the last revision: > > less changes with suggestions from @liach It would seem the specialization for `Ljava/lang/Object;` (via `String::regionMatches`) hurts interpreted performance, putting into doubt whether that optimization is fruitful for startup performance. `-Xint` numbers: Name (descString) Cnt Base Error Test Error Unit Change ofDescriptor (Ljava/lang/Object;Ljava/lang/String;)I 6 7734,757 ± 154,894 10463,211 ± 61,369 ns/op 0,74x (p = 0,000*) ofDescriptor ()V 6 1346,374 ± 56,956 527,418 ± 54,952 ns/op 2,55x (p = 0,000*) ofDescriptor (Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object; 6 9873,260 ± 118,592 13512,378 ± 44,295 ns/op 0,73x (p = 0,000*) ofDescriptor (Ljava/lang/String;Ljava/lang/String;)Ljava/lang/String; 6 9790,973 ± 196,979 15078,814 ± 154,289 ns/op 0,65x (p = 0,000*) ofDescriptor (Ljava/lang/Integer;Ljava/lang/Integer;)Ljava/lang/Integer; 6 9963,069 ± 126,510 9610,144 ± 1952,719 ns/op 1,04x (p = 0,270 ) ofDescriptor ()Ljava/lang/Object; 6 3730,028 ± 757,223 4314,956 ± 460,108 ns/op 0,86x (p = 0,002*) ofDescriptor ([IJLjava/lang/String;Z)Ljava/util/List; 6 8909,754 ± 93,260 9004,239 ± 917,012 ns/op 0,99x (p = 0,512 ) ofDescriptor ()[Ljava/lang/String; 6 3710,475 ± 171,494 3159,694 ± 67,448 ns/op 1,17x (p = 0,000*) ofDescriptor (..IIJ)V 6 18670,031 ± 257,048 17178,329 ± 544,327 ns/op 1,09x (p = 0,000*) ofDescriptor ([III.Z[B..[.[B). 6 45623,579 ± 8342,076 46138,662 ± 13494,653 ns/op 0,99x (p = 0,829 ) ofDescriptor (.....................). 6 166686,442 ± 3550,565 167529,385 ± 11210,813 ns/op 0,99x (p = 0,640 ) * = significant ------------- PR Comment: https://git.openjdk.org/jdk/pull/20611#issuecomment-2298473472
