#Microbenchmarks for int[] to String base-16 conversion in Java.
From the SO question: How to convert int array to hex string
This code uses JMH for microbenchmarking.
Sample benchmark results are:
>java -jar target/benchmarks.jar TextBench -wi 5 -i 10 -f 3
| N | Alt / ns | error / ns | Simple / ns | Error / ns | Speed up |
|---|---|---|---|---|---|
| 1 | 30 | 1 | 61 | 2 | 2.0x |
| 100 | 852 | 19 | 3,724 | 99 | 4.4x |
| 1,000 | 7,517 | 200 | 36,484 | 879 | 4.9x |
| 10,000 | 82,641 | 1,416 | 360,670 | 5,728 | 4.4x |
| 100,000 | 1,014,612 | 241,089 | 4,006,940 | 91,870 | 3.9x |
| 1,000,000 | 9,929,510 | 174,006 | 41,077,214 | 1,181,322 | 4.1x |
| 10,000,000 | 182,698,229 | 16,571,654 | 432,730,259 | 13,310,797 | 2.4x |
Note these speed-up factors are different to those originally published using Caliper.
This has nothing to do with Caliper but rather as the original results were done with a test that did not put anything other than 0s into the int[] test array. This resulted in JVM optimisations that gave artificially high performances. The above speed-up factors can be closely reproduced in Caliper.
##Project structure
This maven-based project contains the text package with 4 classes:
- IntArrToStringConverter.java: A common interface to allow caliper based benchmarking comparing different approaches to base-16 text encoding for an
int[] - SimpleConverter.java: The (corrected) encoder proposed by Malt's answer
- AltConverter.java: The alternative encoder proposed by Andrew's answer
- TextBench.java: The benchmark test file
#Installing JMH
This is a maven project, so if it is set up correctly then mvn clean install should work.
#Running the tests
Use Eclipse to develop the code, but run the tests from the console:
mvn clean install
java -jar target/benchmarks.jar TextBench -wi 5 -i 10 -f 3