On Wed, 13 Oct 2021 18:55:10 GMT, Vamsi Parasa <d...@openjdk.java.net> wrote:
> Optimize the new Math.unsignedMultiplyHigh using the x86 mul instruction. > This change show 1.87X improvement on a micro benchmark. test/micro/org/openjdk/bench/java/lang/MathBench.java line 547: > 545: return Math.unsignedMultiplyHigh(long747, long13); > 546: } > 547: As far as I can tell, the JMH overhead dominates when trying to measure the latency of events in the nanosecond range. `unsignedMultiplyHigh` should have a latency of maybe 1.5-2ns. Is that what you saw? ------------- PR: https://git.openjdk.java.net/jdk/pull/5933
