Re: user instruction tracing patch?

["Frank Ch. Eigler" <fche@redhat.com>]

Hi -

On Fri, Nov 16, 2007 at 01:07:47PM -0800, Jim Keniston wrote:
> [...]
> Sorry, I still don't get it then.  Given
> 	probe program("/bin/vi").function("malloc") if (mp) { .. }
> if some handler executes
> 	mp = 1;
> how does stap know which instance(s) of vi to probe?

None of this exists yet, but it should work similarly to kprobes
where lack of probe point qualification means "all of them".  So

   probe program("/bin/vi").function("malloc")  { }

would be a request to probe all running (and forseeably, any future)
copies of vi.  To filter further, I imagine additional qualifiers such
as ".pid(NUM)", ".uid(NUM)".  These are all to identify the potential
probing target processes.


The conditional enable/disable stuff is intended to be orthogonal.
They do not create or destroy probing targets/opportunities, merely
turn them on or off.

- FChE