tracing-compilation-events

To trace Truffle compilation events, run the launcher with --experimental-options and --engine.TraceCompilation. This logs timing, tier levels, success/failure status, and invalidation reasons to diagnose tiering and bailouts.

Deoptimization and compilation failures in GraalVM runtime profiling are caused by invalidations and bailouts. Tracing compilation events logs these specific reasons, helping you identify why hot code failed to compile or was invalidated.

You can track code recompilation cycles across tier1 and tier2 during benchmarks by tracing compilation events. This records timing and tier transitions, showing how frequently functions recompile under benchmark workloads.

Tracing compilation timing requires no additional dependencies, but needs the Truffle/GraalVM runtime environment. You must enable data collection by starting the launcher with --experimental-options and --engine.TraceCompilation.

The best way to root-cause performance warnings related to Truffle compilation is to combine compilation event tracing with detecting-performance-warnings. This contextual analysis links timing, failures, and invalidation reasons to broader performance issues.