RFR: 8196106: Support nested infinite or recursive flat mapped streams
Viktor Klang
vklang at openjdk.org
Tue Apr 9 10:00:38 UTC 2024
This PR implements Gatherer-inspired encoding of `flatMap` that shows that it is both competitive performance-wise as well as improve correctness.
Below is the performance of `Stream::flatMap` (for reference types):
Before this PR:
Benchmark (size) Mode Cnt Score Error Units
FlatMap.par_array 10 thrpt 12 294008,937 ? 54369,110 ops/s
FlatMap.par_array 100 thrpt 12 62411,229 ? 14868,119 ops/s
FlatMap.par_array 1000 thrpt 12 8263,821 ? 452,622 ops/s
FlatMap.par_iterate 10 thrpt 12 23029,978 ? 4274,449 ops/s
FlatMap.par_iterate 100 thrpt 12 10532,907 ? 321,694 ops/s
FlatMap.par_iterate 1000 thrpt 12 981,571 ? 135,270 ops/s
FlatMap.seq_array 10 thrpt 12 2955648,495 ? 32539,142 ops/s
FlatMap.seq_array 100 thrpt 12 41851,009 ? 377,546 ops/s
FlatMap.seq_array 1000 thrpt 12 1740,281 ? 1229,974 ops/s
FlatMap.seq_iterate 10 thrpt 12 321727,690 ? 5149,356 ops/s
FlatMap.seq_iterate 100 thrpt 12 8437,198 ? 56,635 ops/s
FlatMap.seq_iterate 1000 thrpt 12 76,994 ? 0,965 ops/s
After this PR:
Benchmark (size) Mode Cnt Score Error Units
FlatMap.par_array 10 thrpt 12 283350,051 ? 35567,223 ops/s
FlatMap.par_array 100 thrpt 12 53846,906 ? 19241,913 ops/s
FlatMap.par_array 1000 thrpt 12 8230,909 ? 156,362 ops/s
FlatMap.par_iterate 10 thrpt 12 26328,500 ? 5411,401 ops/s
FlatMap.par_iterate 100 thrpt 12 10470,862 ? 249,991 ops/s
FlatMap.par_iterate 1000 thrpt 12 986,511 ? 224,050 ops/s
FlatMap.seq_array 10 thrpt 12 5654826,565 ? 27317,453 ops/s
FlatMap.seq_array 100 thrpt 12 187929,786 ? 542,787 ops/s
FlatMap.seq_array 1000 thrpt 12 2385,346 ? 9,827 ops/s
FlatMap.seq_iterate 10 thrpt 12 812722,403 ? 160500,399 ops/s
FlatMap.seq_iterate 100 thrpt 12 13542,472 ? 118,769 ops/s
FlatMap.seq_iterate 1000 thrpt 12 157,056 ? 1,814 ops/s
-------------
Commit messages:
- Adding JavaDoc to isShortCircuitingPipeline()
- Removing the use of @Stable
- Adding conditional logic to optimize for non-shortcircuiting flatmaps
- Converting the Int/Long/DoublePipelines
- Switching flatMap implementations to ones inspired by Gatherer encoding
Changes: https://git.openjdk.org/jdk/pull/18625/files
Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=18625&range=00
Issue: https://bugs.openjdk.org/browse/JDK-8196106
Stats: 409 lines in 8 files changed: 236 ins; 84 del; 89 mod
Patch: https://git.openjdk.org/jdk/pull/18625.diff
Fetch: git fetch https://git.openjdk.org/jdk.git pull/18625/head:pull/18625
PR: https://git.openjdk.org/jdk/pull/18625
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