Java FFI benchmarks

Benchmarks for Java JNI (using JavaCPP) vs Project Panama with JDK (openjdk 19-panama 2022-09-20)

Setup instructions for benchmark:

Clone the project

git clone https://github.com/deepu105/Java-FFI-benchmarks.git

Setup Java 19 panama EA build using SDK man

sdk install java 19.ea.1.pma-open
sdk use java 19.ea.1.pma-open

Create Java bindings for unistd.h using jextract

Linux

export C_INCLUDE=/usr/include
jextract --source -d generated/src/main/java -t org.unix -I $C_INCLUDE $C_INCLUDE/unistd.h

macOS

export C_INCLUDE=/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include
jextract --source -d generated/src/main/java -t org.unix -I $C_INCLUDE $C_INCLUDE/unistd.h

Build and run using Maven

When running the benchmark it by default only works for Linux. For macOS uncomment the appropriate function in src/main/java/org/sample/FFIBenchmark.java

mvn clean verify
java -jar target/benchmarks.jar

Typical Results

These results vary because they were ran on a developer machine with other services running. Also, according to the JMH docs, to avoid blackholes (methods that return void). e.g. If you call getPid() and return void the JVM will optimize by removing dead code. To ensure the code isn't removed the method returns a primitive (int).

Below are some results (smaller numbers are better).

macOS (JDK 17)

Benchmark                    Mode  Cnt  Score   Error  Units
FFIBenchmark.JNI             avgt   40  9.698 ± 0.532  ns/op
FFIBenchmark.panamaDowncall  avgt   40  8.431 ± 0.096  ns/op
FFIBenchmark.panamaJExtract  avgt   40  8.488 ± 0.099  ns/op

Linux (JDK 19)

Benchmark                    Mode  Cnt   Score   Error  Units
FFIBenchmark.JNI             avgt   40  50.221 ± 0.512  ns/op
FFIBenchmark.panamaDowncall  avgt   40  49.382 ± 0.701  ns/op
FFIBenchmark.panamaJExtract  avgt   40  49.946 ± 0.721  ns/op