> I understood that there is a way to ask for the current JITted code -> > symtab, my question was specifically about how to get notifications when > those mappings change.
JVMTI has a callback interface, so you can register call backs for specific events: http://docs.oracle.com/javase/7/docs/platform/jvmti/jvmti.html#EventSection > When we use mmap(addr, len, PROT_EXEC) the kernel has a meta event > called PERF_RECORD_MMAP that will record addr range, symtab DSO path, > and we ask it to be timestamped, how to do that for the equivalent part > in the JVM? The CompiledMethodLoad callback would trigger that event. > > My initial thought was to find that using perf probe and insert there a > probe point, but I think that there may be already an existing > tracepoint in the jvm for that, one that, from what I've read so far, > is _not_ being used by this java perf agent, right? It's not needed. Java already has all the needed hooks. Maybe for some different JITs. > > From what I understood, how would it insert that event into the > perf.data event stream? Only if it necessarily involved a new mmap, via > the kernel, etc. That's the new interface to be defined. Just write a perf.data? -Andi -- [email protected] -- Speaking for myself only. -- To unsubscribe from this list: send the line "unsubscribe linux-perf-users" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
