For some stubs we actually do not generate code on PPC64 but instead use a native C-function with inline-assembly. If the generators of these stubs contain a StubCodeMarks, they will trigger JvmtiExport::post_dynamic_code_generated_internal events with a zero length code size. This may fool clients like Oprofile which register for these events (thanks to Maynard Johnson who reported this - see http://mail.openjdk.java.net/pipermail/ppc-aix-port-dev/2014-June/002032.html).