GraalPython support in JBang

[wfouche]

Starting a discussion exploring support for GraalPython in JBang. Is it feasible, how would it work, what are the benefits and limitations?

GraalPython in located in Maven Central at:

<dependency>
    <groupId>org.graalvm.polyglot</groupId>
    <artifactId>python</artifactId>
    <version>24.1.2</version>
</dependency>

GraalPython is a Python 3.11 compliant runtime on top of the GraalVM (JVM):

• https://github.com/oracle/graalpython/releases
• https://www.graalvm.org/python/
• https://www.graalvm.org/latest/reference-manual/python/standalone-applications/
• https://www.graalvm.org/latest/reference-manual/python/Modern-Python-on-JVM/#migrating-jython-scripts

[wfouche]

Moving from Jython to GraalPython:

• https://github.com/graalvm/graal-languages-demos/tree/main/graalpy/graalpy-jython-guide

GraalPython with JBang integration demo:

• https://github.com/graalvm/graal-languages-demos/tree/main/graalpy/graalpy-jbang-qrcode/

[wfouche]

// Install the Graal VM
$ sdk install java 23.0.2-graal

// Run the Graal Python code
$ time jbang run qrcode.java "Hello from GraalPy!"

[jbang] Resolving dependencies...
[jbang]    org.graalvm.python:python-language:24.1.2
[jbang]    org.graalvm.python:python-launcher:24.1.2
[jbang]    org.graalvm.python:python-resources:24.1.2
[jbang]    org.graalvm.python:python-embedding:24.1.2
[jbang]    org.graalvm.python:python-embedding-tools:24.1.2
[jbang] Dependencies resolved
[jbang] Building jar for qrcode.java...
[jbang] Post build with org.graalvm.python.embedding.tools.jbang.JBangIntegration

real    2m13.024s
user    4m57.199s
sys     0m10.572s

The first run took 2+ minutes to complete. The second run finished in 11 seconds.

$ time jbang run qrcode.java "Hello from GraalPy!"

real    0m10.973s
user    0m26.484s
sys     0m0.961s

Both times the following warning was printed on the console. This should be further investigated.

[engine] WARNING: The polyglot engine uses a fallback runtime that does not support runtime compilation to native code.
Execution without runtime compilation will negatively impact the guest application performance.
The following cause was found: JVMCI is required to enable optimizations. Pass -XX:+EnableJVMCI as a virtual machine argument to the java executable to resolve this.
For more information see: https://www.graalvm.org/latest/reference-manual/embed-languages/#runtime-optimization-support.
To disable this warning use the '--engine.WarnInterpreterOnly=false' option or the '-Dpolyglot.engine.WarnInterpreterOnly=false' system property.

Experimental run with EnableJVMCI enabled.

$ export JBANG_JAVA_OPTIONS="-XX:+UnlockExperimentalVMOptions -XX:+EnableJVMCI"
$ time jbang run qrcode.java "Hello from GraalPy!"

[engine] WARNING: The polyglot engine uses a fallback runtime that does not support runtime compilation to native code.
Execution without runtime compilation will negatively impact the guest application performance.
The following cause was found: No optimizing Truffle runtime found on the module or class-path.
For more information see: https://www.graalvm.org/latest/reference-manual/embed-languages/#runtime-optimization-support.
To disable this warning use the '--engine.WarnInterpreterOnly=false' option or the '-Dpolyglot.engine.WarnInterpreterOnly=false' system property.

real    0m10.893s
user    0m32.548s
sys     0m1.307s

Experimental run with EnableJVMCI enabled and Interpreter Warning set to false.

$ export JBANG_JAVA_OPTIONS="-XX:+UnlockExperimentalVMOptions -XX:+EnableJVMCI -Dpolyglot.engine.WarnInterpreterOnly=false"

$ time jbang run qrcode.java "Hello from GraalPy!"

real    0m11.330s
user    0m33.603s
sys     0m1.315s

TBD - test with optimizing Truffle runtime installed / enabled.