dtrace discuss - Dec 2007 - cross-process tracing?

I''m looking at my web stack : it goes firefox -> ruby ->
postgresql.

All those things have DTrace hooks in them, so it''d be great to be
able to follow
e.g. a user clicking on a submit button through the rails stack and
down into the database
(they can all be on the same box if need be).

I''ve read a few chapters into the DTrace guide, and can see how you
track user threads across
providers.

I''m trying to figure out how I''d match up the probes firing
across the
different processes.
How do the gurus do this kind of thing?

-- 
Rasputnik :: Jack of All Trades - Master of Nuns
http://number9.hellooperator.net/

> I''m trying to figure out how I''d match up the probes
firing across the
> different processes.
> How do the gurus do this kind of thing?
The easiest scenario is if there''s a single thread of control that you
can
follow across all the layers of the stack. You can do this simply with
thread-local variables in DTrace. Alternatively, you can find some message
handle to correlate events across diferent layers of the stack in different
languages.

Adam

-- 
Adam Leventhal, FishWorks                        http://blogs.sun.com/ahl