speedup factors of the proposed re-implementation of Double.toString(double) (original) (raw)

raffaello.giulietti at gmail.com raffaello.giulietti at gmail.com
Fri May 11 14:02:43 UTC 2018

Hi,

in order to elicit some concrete interest in the proposed re-implementation of Double.toString(double) [1] to overcome the known issues [2], I prepared a jar in [3] that runs some benchmarks comparing the execution times.

It can be executed directly as: java --module-path todecbench.jar -m todec

The source code has already been delivered in [4].

The proposed implementation corrects all the known anomalies and the benchmarks show that it is faster.

While I have no opportunities to run the benchmarks on idle server class hardware, the speedup factors obtained on my not so recent laptop (i7-3630QM @ 2.4 GHz, 12 GiB RAM, Windows 10 Pro 64 bit, Oracle java 9.0.4 64 bit) are:

Not shown in the benchmark, but collected over extensive testing, are speedup factors in-between.

In about 99.4% of the cases no objects are ever allocated (except for the final result), which helps reducing gc costs. For details about the algorithmic part see the pdf in [3].

Hope this helps in getting some of you to try the code and give feedback.

Greetings Raffaello

[1] http://mail.openjdk.java.net/pipermail/core-libs-dev/2018-March/052355.html [2] https://bugs.openjdk.java.net/browse/JDK-4511638 [3] https://drive.google.com/drive/folders/1MErGSOaqDFw2q9rz48WlpBDKyZkLuUqj?usp=sharing [4] http://mail.openjdk.java.net/pipermail/core-libs-dev/2018-April/052696.html

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