CODEWITHSUNDEEP
debuggingerlangtrace
fvarj
fvarj

Reputation: 215

How to print out all data tracked by Erlang dbg

I would like to trace all behavior of Erlang GC using dbg:tracer and print out the tracked events.

1> dbg:tracer().
2> dbg:p(self(), [garbage_collection]).
3> my_module:function([Args]).
4> dbg:stop().
5> dbg:show_trace().
...

I would like to only trace garbage collection during the execution of my_module:function/0 function call. Once the function has returned tracing should stop.

Upvotes: 0

Views: 362

Answers (1)

Stratus3D
Stratus3D

Reputation: 4906

There may be a better way of doing this, but I would suggest turning off tracing as soon as the function you care about has returned. Something like this should work:

1> dbg:tracer().
2> GcOfMyModule = fun() ->
    dbg:p(self(), [garbage_collection]),
    my_module:function([Args]),
    dbg:stop()
end
3> GcOfMyModule().
5> dbg:show_trace().

Wrapping the dbg:p/2, my_module:function/1, and dbg:stop/0 calls all in one function will mean each function will be executed immediately after the function before it. I got idea originally from the last part of this answer where it takes about automatically stopping a trace after a certain number of events https://stackoverflow.com/a/1954980/1245380.

Upvotes: 1

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