JMH Benchmark and passing java String to JExtracted Swift

[ktoso]

./gradlew jmh -PjmhIncludes="StringPassingBenchmark"

We can now import and call Swift methods like these:

public func globalWriteString(string: String) -> Int

Which shows up as:

public static long globalWriteString(java.lang.String string)

As a quick check on my M1 macbook pro:

Benchmark                                      (stringLen)  Mode  Cnt     Score     Error  Units
JavaToSwiftBenchmark.getInt_global_jni                 N/A  avgt   10   415.097 ±   1.747  ns/op
JavaToSwiftBenchmark.getInt_member_ffi                 N/A  avgt   10    28.762 ±   3.204  ns/op
JavaToSwiftBenchmark.jextract_getInt_ffm               N/A  avgt   10     4.019 ±   1.693  ns/op
StringPassingBenchmark.writeString_baseline              5  avgt   20     0.852 ±   0.019  ns/op
StringPassingBenchmark.writeString_baseline             10  avgt   20     0.864 ±   0.040  ns/op
StringPassingBenchmark.writeString_baseline            100  avgt   20     0.854 ±   0.025  ns/op
StringPassingBenchmark.writeString_baseline            200  avgt   20     0.881 ±   0.019  ns/op
StringPassingBenchmark.writeString_global_fmm            5  avgt   20    69.695 ±   5.692  ns/op
StringPassingBenchmark.writeString_global_fmm           10  avgt   20    71.264 ±   7.830  ns/op
StringPassingBenchmark.writeString_global_fmm          100  avgt   20   262.935 ±   6.474  ns/op
StringPassingBenchmark.writeString_global_fmm          200  avgt   20   393.893 ±   2.259  ns/op
StringPassingBenchmark.writeString_global_jni            5  avgt   20   738.137 ±  46.046  ns/op
StringPassingBenchmark.writeString_global_jni           10  avgt   20   744.462 ±  53.125  ns/op
StringPassingBenchmark.writeString_global_jni          100  avgt   20  1001.133 ±  40.182  ns/op
StringPassingBenchmark.writeString_global_jni          200  avgt   20  1246.412 ± 101.190  ns/op

I did not manage to get the _jni version to link properly yet but will do that next.