An easy-way to profile apps visually

[Guillaume Piolat]

tl;dr Simply generates a JSON that follows the Trace Event Format.

Trace Event Format is a simple JSON format that is then read by 
web apps like:
  - chrome://tracing
  - https://ui.perfetto.dev/

You can get images of your instrumented program like that very 
easily:
https://imgur.com/a/q4Uwosz

Surprisingly, TLS really shines there, since you can collect the 
JSON trace in a thread-local manner and concatenate the output at 
the end. Though, the reallocs will get more and more expensive as 
time goes by. The profile size balloons easily.

All in all I think explicit frame profiling like that is a 
valuable alternative to either sampling or instrumentation 
profiler. At least you can finally visualize parallelism and how 
much of it is synchronization.

Profiler implementation in dplug:gui => 
https://github.com/AuburnSounds/Dplug/blob/master/gui/dplug/gui/profiler.d (haven't tested outside Windows for now... I was surprised synchronization stuff was relatively lightweight), it would be a small deal of work to strip it of its library.