In order to see object allocations, monitor events, and Java method entries and returns from DTrace, the VM must either be started with the -XX:+ExtendedDTraceProbes, or by using jinfo to turn on that flag dynamically. The performance impact is significant, so the user cannot always run with -XX:+ExtendedDTraceProbes, and the jinfo solution requires additional user work. We should come up with some way to turn these probes on and off dynamically (and individually) when DTrace monitors them.
The C2 compiler does aggressive inlining of method calls. These inlined frames do now show up on a stack produced by DTrace's jstack(). The pstack command can display these frames using VM data structures (virtual frames). We need a way to view these frames with DTrace as well.