Pause and resume profiling around forks #115
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Otherwise the child will hang forever on exit when trying to dump the profiling data. Which is problematic when trying to profile some programs. There might be more elegant ways to handle it, this is mostly a proof of concept. Also it's not quite fully working, the test passes alone, but but if ran after some other specific tests, it end up in a SIGTRAP, which I'm not sure why: ``` bundle exec rake SEED=26641 TESTOPTS="-v" ... 1) Failure: TestVernier#test_that_forked_children_do_not_hang [test/test_vernier.rb:15]: Expected #<Process::Status: pid 63146 SIGTRAP (signal 5)> to be success?. ```
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Would love to see something like this merged - it took me a while to figure out that the reason vernier seemed to be hanging forever was a chunk of code using |
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Based on #82
I think there's more I can simplify here still. After implementing all of it I'm not sure that pause/resume need to be separate from start/stop.
I'll also want to make something more efficient than running
ObjectSpace.each_objecton every fork. This also does leave a possible race condition where if you are spawning new threads which are themselves making new profiles as you fork we may miss one to disable, but I'm reasonably happy ignoring that for now.