j_classflow.d - trace a Java class method flow using DTrace. j_classflow.d classname This traces activity from all Java processes on the system with hotspot provider support (1.6.0) and the flag "+ExtendedDTraceProbes". eg, java -XX:+ExtendedDTraceProbes classfile This watches Java method entries and returns, and indents child method calls. Solaris Evolving - uses the DTrace hotspot provider, which may change as additional features are introduced. Check Java/Readme to see what version these scripts are based on.

Default output, # j_classflow.d

C CPU-id

TIME(us) Time since boot, us

PID Process ID

CLASS.METHOD Java class and method name

-> method entry

<- method return

Watch the first column carefully, it prints the CPU-id. If it changes, then it is very likely that the output has been shuffled. Changes in TID will appear to shuffle output, as we change from one thread depth to the next. See Docs/Notes/ALLjavaflow.txt for additional notes.

See the DTraceToolkit for further documentation under the Examples, Notes and Docs directories. The example files may be especially useful as they aim to demonstrate how to interpret the output. j_classflow.d will run until Ctrl-C is hit. Brendan Gregg [CA, USA] dtrace(1M)