RFR: 8229283: StringLatin1 should consistently use CharacterDataLatin1.instance when applicable

Jim Laskey james.laskey at oracle.com
Fri Aug 9 00:41:38 UTC 2019


> On Aug 8, 2019, at 8:28 AM, Claes Redestad <claes.redestad at oracle.com> wrote:
> Hi,
> in j.l.StringLatin1 we can and do call CharacterDataLatin1 directly in
> some places, which avoids a few indirections. Doing so has no effect on peak performance, but simplifies the work the JIT needs to do and speeds
> up a variety of operations during startup and warmup.
> http://cr.openjdk.java.net/~redestad/8229283/open.00/
> https://bugs.openjdk.java.net/browse/JDK-8229283
> Pre-existing StringUpperLower microbenchmark sees 1.5-1.9x
> improvements when run with -Xint or -XX:TieredStopAtLevel=1. Affected
> operations are very common, so there are tiny but measurable gains
> across a diverse set of startup tests.
> Thanks!
> /Claes

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