[erlang-questions] tracing tools

[Vlad Dumitrescu]

Hi all,

Tracing a system is the only reasonable way to really see what is
going on with it for debugging or instructional purposes (for systems
of at least "normal" complexity and size). If we could trace
everything, then given appropriate tools we could see exactly what
happened when at a post-mortem, without guessing from incomplete logs.
Unfortunately, tracing everything is prohibitive in the really useful
cases (i.e. with large systems). Tools like inviso have been created
to try to alleviate this, but it doesn't feel like they succeeded
(inviso will become deprecated).

What I wonder is if there has been any work on improving tracing
performance or if there are any plans in that direction. It might be
so that the latest SMP improvements could allow for tracing to have
less impact on the system's performance.

Also, given that there are several tools that are using tracing in the
background (like percept), I had moments where I wished that I could
run those together with my "regular" debug-tracing. Since tracing is a
global service, that would not be a good idea at the moment, but would
it be possible to make it so?

I am also considering some tools that will monitor a system and
start/stop relevant tracing according to its configuration and that
can "replay" a trace and allow investigating the system's state.

best regards,
Vlad