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I would like to see a log of all the emacs lisp function calls made during an emacs session.

I want to know exactly what the interpreter is doing. How can "intercept" the interpreter's REPL, if that makes any sense?

With strace I can attach to the emacs process and see all the system calls. But I need higher level information about which lisp functions are actually responsible.

As an aside, the motivation for this is to debug a problem in my emacs session where the emacs process keeps listening on a socket that is forever unavailable:

recvfrom(4, 0xbd4754, 4096, 0, 0, 0)    = -1 EAGAIN (Resource temporarily unavailable)



# netstat -p |grep 14854
unix  3      [ ]         STREAM     CONNECTED     14854    3040/emacs
ealfonso
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3 Answers3

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You can try M-x profile-start RET RET ... M-x profile-report RET. It won't give you a complete trace, but it will show you the call tree for any function that lasted enough time.

BTW, I have no idea what problem you're trying to track. Calling recvfrom and getting EAGAIN over and over again might be completely normal.

Stefan
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  • Good hint. There is obviously a way to tweak the profiler to do exactly what I want to do. Also, the problems that I'm tracking are various, particularly emacs taking a randomly long time for random operations. Maybe you're right and what I noticed in the strace isn't particularly relevant. – ealfonso Dec 05 '13 at 07:06
  • As soon as I get time to consider your solution I will get back to this. – ealfonso Dec 05 '13 at 07:10
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The Elisp info manual comes with a node

18.2.12 Trace Buffer

As stuff mentioned relies on edebug, should be a way to work from trace-point to trace-point and eventually kill.

WRT to logging, that might be done already with trace-function from trace.el.

_

Andreas Röhler
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  • So I don't want to attach to the execution of a specific function, but rather to all functions that are called during an emacs session. I've done an apropos `trace` but do not see `edebug-tracing` function nor is the variable `edebug-trace` defined. I've set `edebug-trace` to t, but so far no trace buffer has showed up. Where is this functionality provided? – ealfonso Dec 01 '13 at 09:37
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I'm not aware of anything which traces all function calls. That would surely need to be implemented in C. Maybe there are some existing debug compilation options you could use?

The following might still prove useful for more targeted debugging. (Emacs will certainly grind to a halt if you attempt to make them trace All The Things, however.)

Both libraries have usage details in their commentary.

Trace:

M-x find-library RET trace RET

;; M-x trace-function FUNCTION &optional BUFFER
;; M-x untrace-function FUNCTION
;; M-x untrace-all

Emacs Lisp Profiler (ELP):

M-x find-library RET elp RET

;; M-x elp-instrument-package
;; M-x elp-instrument-list
;; M-x elp-instrument-function
;; M-x elp-reset-*
;; M-x elp-results
;; M-x elp-restore-all
phils
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