Issue #9321 has been updated by drkaes (Stefan Kaes).


@ko1: Why do you think the second patch creates a performance problem?

Module#const_missing is an exceptional case. Am I missing something?

@tmm1: the stack tracking approach breaks down if the method id reported on return by ruby does not match the one reported on call; which I have seen happening in the past.


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Bug #9321: rb_mod_const_missing does not generate a c-return event
https://bugs.ruby-lang.org/issues/9321#change-44021

Author: drkaes (Stefan Kaes)
Status: Open
Priority: Normal
Assignee: 
Category: core
Target version: 
ruby -v: ruby 2.1.0p1 (2013-12-26 revision 44431) [x86_64-darwin12.0]
Backport: 1.9.3: UNKNOWN, 2.0.0: UNKNOWN, 2.1: UNKNOWN


We have had an issue reported for ruby-prof where execution times were attributed incorrectly in the call graph.

It turned out that the problem is caused by a missing c-return event for Module#const_missing.

ruby-prof simulates the ruby call stack by subscribing to line, call, c-call, return and c-return events.

Obviously, the missing return throws ruby-prof off the track.



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