> When analyzing (startup) performance of the Classfile API I found this > opportunity to further improve `MethodTypeDescImpl::descriptorString`. > > Performance improves across the board in existing microbenchmarks: > > Name > (descString) Cnt Base Error Test Error Unit Change > MethodTypeDescFactories.descriptorString > (Ljava/lang/Object;Ljava/lang/String;)I 6 55,179 ± 2,027 32,920 ± 1,189 > ns/op 1,68x (p = 0,000*) > MethodTypeDescFactories.descriptorString > ()V 6 17,689 ± 1,871 11,060 ± 0,331 ns/op 1,60x (p = 0,000*) > MethodTypeDescFactories.descriptorString > ([IJLjava/lang/String;Z)Ljava/util/List; 6 86,627 ± 1,646 41,035 ± 0,636 > ns/op 2,11x (p = 0,000*) > MethodTypeDescFactories.descriptorString > ()[Ljava/lang/String; 6 18,305 ± 1,974 13,110 ± 0,089 ns/op 1,40x (p = > 0,000*) > * = significant > > > The improvement is even more pronounced when running with `-Xint`, which is > relevant for reducing startup overheads of early ClassFile API use: > > Name > (descString) Cnt Base Error Test Error Unit Change > MethodTypeDescFactories.descriptorString > (Ljava/lang/Object;Ljava/lang/String;)I 6 5122,061 ± 81,335 2626,481 ± > 101,466 ns/op 1,95x (p = 0,000*) > MethodTypeDescFactories.descriptorString > ()V 6 3481,316 ± 258,904 1489,267 ± 15,506 ns/op 2,34x (p = 0,000*) > MethodTypeDescFactories.descriptorString > ([IJLjava/lang/String;Z)Ljava/util/List; 6 7741,081 ± 1628,244 3281,778 ± > 41,892 ns/op 2,36x (p = 0,000*) > MethodTypeDescFactories.descriptorString > ()[Ljava/lang/String; 6 3677,803 ± 63,432 1495,291 ± 8,995 ns/op > 2,46x (p = 0,000*) > * = significant > ``` > > I also applied similar approach to `MethodTypeDesc::displayDescriptor`: > while not performance sensitive I think these are so inter-related that it > makes sense to implement them in a similar fashion.
Claes Redestad has updated the pull request incrementally with one additional commit since the last revision: Calculate length precisely ------------- Changes: - all: https://git.openjdk.org/jdk/pull/18945/files - new: https://git.openjdk.org/jdk/pull/18945/files/2979847c..15c8d39c Webrevs: - full: https://webrevs.openjdk.org/?repo=jdk&pr=18945&range=02 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=18945&range=01-02 Stats: 22 lines in 3 files changed: 8 ins; 4 del; 10 mod Patch: https://git.openjdk.org/jdk/pull/18945.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/18945/head:pull/18945 PR: https://git.openjdk.org/jdk/pull/18945
