Linux time sample based profiler

Try Zoom - I believe it will let you profile all processes - it would be interesting to know if it highlights your problem in this case.

I wrote this a long time ago, only because I couldn't find anything better: https://github.com/dicej/profile

I just found this, too, though I haven't tried it: https://github.com/oliver/ptrace-sampler

Glad you asked. I believe OProfile can be made to do what I consider the right thing, which is to take stack samples on wall-clock time when the program is being slow and, if it won't let you examine individual stack samples, at least summarize for each line of code that appears on samples, the percent of samples the line appears on. That is a direct measure of what would be saved if that line were not there. Here's one discussion. Here's another, and another. And, as Paul said, Zoom should do it.

If your time went from 60 sec to 1 sec, that implies every single stack sample would have had a 59/60 probability of showing you the problem.