new events for TracePoint thread_begin/end, b_call/b_end
On the trunk, there are new 4 events for TracePoint.
* vm_trace.c: add events * :thread_begin - hook at thread beggining. * :thead_end - hook at thread ending. * :b_call - hook at block enter. * :b_return - hook at block leave. This change slow down block invocation. Please try and give us feedback until 2.0 code freeze.
bcall and breturn are proposed at [Feature #6649].
On my environment, bcall/breturn cause 15% speed-down with
null block invocation micro-benchmark.
Please try and give us feedback.
It is easy to revert until code freeze.