The changes made in JDK-8193210 supports only bulk registration of JFR CompilePhaseType names[1]. However, Graal only registers compiler phases upon their first execution since the set of phases in use is not known at VM initialization. This means registration of Graal phases needs to do a bunch of marshaling, unmarshaling and data shuffling for each phase registration. This can be removed by having the low level interface be in terms of a registering a single phase.

[1] https://github.com/openjdk/jdk/blob/4e6a4af1866d0007d368b78bf78b6a8e1c8be425/src/hotspot/share/compiler/compilerEvent.hpp#L75