Hello,
curious about Double.toString(double) performance?
Here are the results obtained by jmh 1.23 on a recent changeset [1]. The
benchmark is over the full range of bitwise uniformly distributed random
doubles.
# VM options: <none>
# Warmup: 5 iterations, 10 s each
# Measurement: 5 iterations, 10 s each
...
Benchmark Mode Cnt Score Error Units
DoubleToStringBenchmark.test avgt 25 1251.658 ± 211.068 ns/op
showing quite a variability, probably attributable to intervening gc cycles.
The same setup after the integration of the code in [2] to replace
Double.toString(double) with a modern, better specified and correct
implementation (as witnessed by many trillions of fully conformant
outcomes).
# VM options: <none>
# Warmup: 5 iterations, 10 s each
# Measurement: 5 iterations, 10 s each
...
Benchmark Mode Cnt Score Error Units
DoubleToStringBenchmark.test avgt 25 70.712 ± 1.461 ns/op
showing both a speedup of 17.7x on my i7 based laptop of 2013 as well as
predictable running times. The algorithm never generates temporary garbage.
I'm still looking for enthusiastic reviewers: they seem hard to find,
despite monthly reminders... More in [3] and similarly titled posts for
the past 12 months.
Greetings
Raffaello
----
[1] https://hg.openjdk.java.net/jdk/jdk/rev/90882ba9f488
[2] https://cr.openjdk.java.net/~bpb/4511638/webrev.04/
[3]
https://mail.openjdk.java.net/pipermail/core-libs-dev/2020-March/065476.html
