JRuby and JDK24 AOTCache experiment

[Charles Oliver Nutter]

On Thu, Feb 13, 2025 at 12:36 PM <ioi.lam at oracle.com> wrote:

> Which build of JDK 24 (or mainline) are you using? There's a recent change
> that turns on -XX:+AOTClassLinking automatically to take advantage of all
> JEP 483 optimizations (including the AOT-linking of lambdas)
>
> https://bugs.openjdk.org/browse/JDK-8348752
>
> If you're using an older JDK 24 build (earlier than JDK 24-b35), you might
> need to add -XX:+AOTClassLinking explicitly.
>
> A good way for checking is with -Xlog:cds,class+load and see how many
> classes you are loading from CDS vs dynamically parsed.
>
I'm running the RC from last week:

$ java -version
openjdk version "24" 2025-03-18
OpenJDK Runtime Environment (build 24+36-3646)
OpenJDK 64-Bit Server VM (build 24+36-3646, mixed mode, sharing)

But perhaps the fix I need is not in this build? I ran the record and
create steps again with -XX:+AOTClassLinking and performance wasn't
substantially changed.

I do see lines like this, though, when I enable logging:

[0.895s][info][class,load]
org.jruby.util.io.FilenoUtil$ReflectiveAccess$$Lambda/0x8000004ea source:
shared objects file
[0.895s][info][class,load]
org.jruby.util.io.FilenoUtil$ReflectiveAccess$$Lambda/0x8000004eb source:
shared objects file

Thanks
>
> - Ioi
> On 2/13/25 7:12 AM, Charles Oliver Nutter wrote:
>
> I figured folks here would be interested to see this experiment using
> AOTCache with JRuby.
>
> https://gist.github.com/headius/1a5cfbc91ed8bacd194f1c592a90c275
>
> I just test the 'hello world' scenario that represents our baseline
> startup, but AOT caching manages to beat the automatic AppCDS startup by a
> bit. More/better training might help here I'm guessing?
>
> This is from the JRuby 10 branch (10-dev) on
> https://github.com/jruby/jruby.git if anyone wants to play with it. Just
> run `./mvnw` and then `bin/ruby` will work. We recently added support for
> AutoCreateSharedArchive so it will use CDS by default. Pass --nocache to
> disable that behavior.
>
> *Charles Oliver Nutter*
> *Architect and Technologist*
> Headius Enterprises
> https://www.headius.com
> headius at headius.com
>
>
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