streams

Java Streams API Benchmark on GraalVM

This demo shows how GraalVM efficiently removes abstractions from high-level programs. The Streams.java file contains a simple query implemented with the Java Streams API:

Arrays.stream(persons)
   .filter(p -> p.getEmployment() == Employment.EMPLOYED)
   .filter(p -> p.getSalary() > 100_000)
   .mapToInt(Person::getAge)
   .filter(age -> age > 40)
   .average()
   .getAsDouble();

Preparation

1. Run this stream with any java you have on your system:

   javac Streams.java

   java Streams 100000 200

   Iteration 20 finished in 114 milliseconds with checksum e6e0b70aee921601
   TOTAL time: 2330
   

2. Download and install the latest GraalVM JDK using SDKMAN!.

   sdk install java 21.0.1-graal

3. Now compile and run the same application on GraalVM:

   $JAVA_HOME/bin/javac Streams.java

   $JAVA_HOME/bin/java Streams 100000 200

   Iteration 20 finished in 21 milliseconds with checksum e6e0b70aee921601
   TOTAL time: 623
   

We can see over 4x speedup on this simple program.

Profile-Guided Optimizations with Native Image

This demo shows how to use profile-guided optimizations (PGO) with the native-image builder.

Note: Profile-guided optimizations is a GraalVM Enterprise feature.

You will use the same Streams.java program that contains a simple query implemented with the Java Streams API:

Arrays.stream(persons)
   .filter(p -> p.getEmployment() == Employment.EMPLOYED)
   .filter(p -> p.getSalary() > 100_000)
   .mapToInt(Person::getAge)
   .filter(age -> age > 40)
   .average()
   .getAsDouble();

1. First, build the native image without profile-guided optimizations:

   $JAVA_HOME/bin/javac Streams.java

   $JAVA_HOME/bin/native-image Streams

   ./streams 100000 200
   

   Iteration 20 finished in 127 milliseconds with checksum e6e0b70aee921601
   TOTAL time: 2589
   

   This version of the program runs about 2x slower than the one on the regular JDK.

2. To enable PGO you need to build an instrumented image:

   $JAVA_HOME/bin/native-image --pgo-instrument Streams

3. Run this instrumented image to collect profiles:

   ./streams 10000 200

   Iteration 20 finished in 62 milliseconds with checksum e1d39d010d08cf01
   TOTAL time: 1279
   

   Profiles collected from this run are now stored in the default.iprof file.

   Note that we run the profiling with a much smaller data size.

4. Now you can use the collected profiles to build an optimized native image:

   $JAVA_HOME/bin/native-image --pgo Streams

5. Then run it:

   ./streams  100000 200

   Iteration 20 finished in 24 milliseconds with checksum e6e0b70aee921601
   TOTAL time: 516
   

You should get the performance comparable to the Java version of the program.

Related Documentation

Optimize a Native Executable with PGO