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Add support for PGO #457
Description
Now that GraalVM 23 is out with PGO support available in the Oracle GraalVM distribution, it would be good if the Gradle and Maven plugins added built-in support for PGO.
For the Gradle plugin, my recommendation would be to add a couple of options to org.graalvm.buildtools.gradle.dsl.NativeImageCompileOptions:
- a
Property<Boolean> getPgo()which can also be enabled via a CLI flag (e.g--pgo), which would enable the compilation with--pgo-instrument(and potentially add a-instrumentedsuffix to the image name for clarity), which would be used for the 1st step, building an image with instrumentation support - a
DirectoryProperty getPgoProfilesDirectory()pointing to a directory of.iproffiles which would be automatically added to the native image compilation ifgetPgo()returns false (and that there are actually files there)
We could have a conventional location of those profile files, for example src/native-image/<image name>/pgo, so for example for the main image it would be src/native-image/main/pgo (with the idea that these files would be checked in VCS).
This is not about the ability to automatically run the instrumented image with a "load test" and automating the process from A-Z, but at least to make it possible to enable PGO in a standard way.
Reacted by Alina Yurenko
Activity
fniephaus commentedon Jun 26, 2023
Thanks for the suggestions, @melix. I've got some comments:
I'd like a CLI flag, but using
--pgofor--pgo-instrumentis probably very confusing, considering there's also a--pgoin Native Image itself. I'd still vote for--pgo-instrumenteven though it's longer.yes, that'd be very useful.
Does this mean that Native Image will automatically pick up the profile stored in a
default.iprofif it is in that directory? What if there are multiple profiles? Maybe users will think Native Image picks up all profiles (native-image-configuresupports merging multiple profiles for example), while it really only picks up thedefault.iprof? Or should/could the plugin run the merge tool and feed the result into Native Image?maybe
pgo-profilesorpgo-data? just an idea :)I'm actually wondering how the iprof files find their way into this new directory for PGO profiles? We probably should provide users with the right
/path/to/image-instrumented -XX:ProfilesDumpFile=full/path/to/src/native-image/main/pgocommand and instructions to make sure the profiles end up in the right directory?Quoting this a second time for another thought: why is this not about the ability to automatically run the instrumented image? I mean the plugins already support running with the tracing agent, couldn't it similarly run the instrumented binary, add the right
-XX:ProfilesDumpFileflag, and tell the user to kill the app when done?Add documentation about PGO support
Add support for PGO instrumentation (#471)