| layout | developer-doc | ||
|---|---|---|---|
| title | Instruments | ||
| category | runtime | ||
| tags |
|
||
| order | 9 |
Instruments are used to track runtime events to allow for profiling, debugging and other kinds of behavior analysis at runtime.
Every Instrument must be implemented in Java and have name that ends with
Instrument.
Annotations are used to register the implemented instruments with Graal. The annotation processor is triggered when recompiling the Java files. Unfortunately, when doing an incremental compilation, only the changed files are recompiled and the annotation processor 'forgets' about other instruments that haven't been recompiled, leading to runtime errors about missing instruments.
To fix that, individual services have to be placed in separate subprojects
depending on runtime and aggregated under runtime-with-instruments. Later
the META-INF registrations are concatenated in the final uber jar.