Async-profiler samples JIT compiler threads as well as Java threads, and hence can show CPU percentage spent on JIT compilation. At the same time, Java methods are different: some take more resources to compile, other take less. Furthermore, there are cases when a bug in C2 compiler causes a JIT thread to stuck in an infinite loop consuming 100% CPU. Async-profiler can highlight which particular Java methods take most CPU time to compile.
The feature can be enabled with the option -F comptask (or its agent equivalent features=comptask).
In some applications, a significant amount of CPU time is spent on dispatching megamorphic virtual/interface calls. async-profiler shows a pseudo-frame on top of v/itable stub with the actual type of object the virtual method is called on. This should make clear the proportion of different receivers for the particular call site.
The feature can be enabled with the option -F vtable (or its agent equivalent features=vtable).
Sometimes, for low-level performance analysis, it is important to know where exactly CPU time is spent inside a method. As an intermediate step to the instruction-level profiling, async-profiler provides an option to record PC address of the currently running method for each execution sample. In this case, each stack trace will include a synthetic frame with the address at the top of every stack trace.
The feature can be enabled with the option -F pcaddr (or its agent equivalent features=pcaddr).