JRuby and JDK24 AOTCache experiment

[ioi.lam at oracle.com]

On 2/13/25 4:14 PM, Charles Oliver Nutter wrote:
> 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
>
24+36 should have the fix, so -XX:+AOTClassLinking should be enabled for 
you. You can check for this log to confirm:

[0.022s][info][cds] Using AOT-linked classes: true (static archive: has 
aot-linked classes)

Thanks

- Ioi


>     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
>>     <https://urldefense.com/v3/__https://gist.github.com/headius/1a5cfbc91ed8bacd194f1c592a90c275__;!!ACWV5N9M2RV99hQ!KZcAz5KTpP2IgI_aftEtgit5ChKERmROAdOTz_Zf0sAGvS4HmvkWVd1FIWtD0H5ntnmOd-VFmRwpRuw$>
>>
>>     I just test the 'hello world' scenario that represents our
>>     baseline startup, but AOT caching manages to beat the automatic
>>     AppCDS startup by a bit. More/better training might help here I'm
>>     guessing?
>>
>>     This is from the JRuby 10 branch (10-dev) on
>>     https://github.com/jruby/jruby.git
>>     <https://urldefense.com/v3/__https://github.com/jruby/jruby.git__;!!ACWV5N9M2RV99hQ!KZcAz5KTpP2IgI_aftEtgit5ChKERmROAdOTz_Zf0sAGvS4HmvkWVd1FIWtD0H5ntnmOd-VFSatN9Qg$>
>>     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
>>     <https://urldefense.com/v3/__https://www.headius.com__;!!ACWV5N9M2RV99hQ!KZcAz5KTpP2IgI_aftEtgit5ChKERmROAdOTz_Zf0sAGvS4HmvkWVd1FIWtD0H5ntnmOd-VFRgsB7Uw$>
>>
>>     headius at headius.com
>
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