On Tue, 9 Feb 2021 12:54:12 GMT, Claes Redestad <redes...@openjdk.org> wrote:
> This refactor some `sun.nio.cs.ext` charsets, such as ISO-2022-CN-GB, > ISO-2022-CN-CNS, ISO-2022-KR and a few others to use static rather than > per-instance auxiliary decoders. Doing so reduce overheads of calling > `charset.newDecoder()`. This reduce or eliminate regressions on `new > String(byte[], String)` operations due the removal of thread-local decoder > caching in [JDK-8259842](https://bugs.openjdk.java.net/browse/JDK-8259842) > > Most ISO-2022 Charsets define a specialized decoder already. The > `ISO2022.Decoder` class was only used by `ISO2022_KR`, so folding it into > that implementation and simplifying the code brings a rather significant > speed-up, both to decoder creation and on actual decoding. > > Testing: tier1-3, manual runs of sun.nio.cs tests `StringDecode.WithCharset.decodeCharsetName` microbenchmark runs pre-JDK-8259842: Benchmark (charsetName) Mode Cnt Score Error Units decodeCharsetName x-ISO-2022-CN-GB avgt 5 756.293 ± 56.082 ns/op decodeCharsetName:·gc.alloc.rate.norm x-ISO-2022-CN-GB avgt 5 488.040 ± 0.013 B/op decodeCharsetName ISO-2022-KR avgt 5 1076.745 ± 299.789 ns/op decodeCharsetName:·gc.alloc.rate.norm ISO-2022-KR avgt 5 808.068 ± 0.022 B/op Current: Benchmark (charsetName) Mode Cnt Score Error Units decodeCharsetName x-ISO-2022-CN-GB avgt 5 906.281 ± 109.035 ns/op decodeCharsetName:·gc.alloc.rate.norm x-ISO-2022-CN-GB avgt 5 920.077 ± 0.025 B/op decodeCharsetName ISO-2022-KR avgt 5 1175.228 ± 144.509 ns/op decodeCharsetName:·gc.alloc.rate.norm ISO-2022-KR avgt 5 1256.105 ± 0.043 B/op Patched: Benchmark (charsetName) Mode Cnt Score Error Units decodeCharsetName x-ISO-2022-CN-GB avgt 5 783.385 ± 255.048 ns/op decodeCharsetName:·gc.alloc.rate.norm x-ISO-2022-CN-GB avgt 5 584.050 ± 0.016 B/op decodeCharsetName ISO-2022-KR avgt 5 814.654 ± 196.860 ns/op decodeCharsetName:·gc.alloc.rate.norm ISO-2022-KR avgt 5 584.050 ± 0.024 B/op ------------- PR: https://git.openjdk.java.net/jdk/pull/2480
