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Profiling with Ctrl-C

I once wrote about how profiler output can be misleading. Someone commented that you don’t need profilers - just Ctrl-C your program in a debugger instead, and you’ll see the call stack where your program probably spends most of its time.

But as my outlook on life worsened with age, I came to think that Ctrl-C profiling deserves a shout-out, because it’s very effective against stupid problems encountered by lazy people operating in unfriendly environments. So I Ctrl-C the thing, and what do you know, there’s one billion stack frames from the nlohmann JSON parser, I guess it all gets inlined in the release build; must be what they call “zero-cost abstraction”. Simulation-based profilers don’t have the problem of losing data to a low sampling frequency - they analyze full instruction traces - but they’re too slow for anything like a production environment.

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