> When generating `MethodHandle`-based concatenation expressions in > `StringConcatFactory` we can reduce the number of classes generated at > runtime by creating small batches of prependers and mixers before binding > them into the root expression tree. > > Improvements on one-off tests are modest, while the improvement on > bootstrapping stress tests can be substantial > ([MixedStringCombinations.java](https://gist.github.com/cl4es/08fb581dece3a73e89bfa52337bc4248)): > > | Build | # classes | Runtime | > | ----------- | ----------------- | --------------- | > | Baseline | 31119 | 2.942s | > | Patch | 16208 | 1.958s | > > An earlier version of this patch saw a regression in the > `StringConcatFactoryBootstraps` microbenchmark. After some refactoring along > with the optimizations in #8881 and #8923 that is no longer the case, and > allocation pressure is down slightly compared to the baseline on such a > repeat-the-same-bootstrap stress test: > > Baseline: > > Benchmark Mode Cnt > Score Error Units > SCFB.makeConcatWithConstants avgt 5 > 2170.039 ? 117.441 ns/op > SCFB.makeConcatWithConstants:?gc.alloc.rate.norm avgt 5 > 3538.020 ? 4.558 B/op > > This patch: > > Benchmark Mode Cnt > Score Error Units > SCFB.makeConcatWithConstants avgt 5 > 2144.807 ? 162.685 ns/op > SCFB.makeConcatWithConstants:?gc.alloc.rate.norm avgt 5 > 3184.943 ? 4.495 B/op
Claes Redestad has updated the pull request incrementally with one additional commit since the last revision: Clarify that consts are always reduced to null, even if calling with constants. Also clarify that the number of constants is paramCount + 1 by refactoring to an array ------------- Changes: - all: https://git.openjdk.java.net/jdk/pull/8855/files - new: https://git.openjdk.java.net/jdk/pull/8855/files/56bdc4c4..444cdd39 Webrevs: - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=8855&range=05 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=8855&range=04-05 Stats: 55 lines in 1 file changed: 15 ins; 13 del; 27 mod Patch: https://git.openjdk.java.net/jdk/pull/8855.diff Fetch: git fetch https://git.openjdk.java.net/jdk pull/8855/head:pull/8855 PR: https://git.openjdk.java.net/jdk/pull/8855
