On Mon, 23 May 2022 20:03:05 GMT, Claes Redestad <redes...@openjdk.org> wrote:
> 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 This pull request has now been integrated. Changeset: 5c39a366 Author: Claes Redestad <redes...@openjdk.org> URL: https://git.openjdk.java.net/jdk/commit/5c39a3664186b91512c6a6cfcd8aa0e9860614ea Stats: 468 lines in 4 files changed: 268 ins; 114 del; 86 mod 8287522: StringConcatFactory: Add in prependers and mixers in batches Reviewed-by: jlaskey, mchung ------------- PR: https://git.openjdk.java.net/jdk/pull/8855
