Message 332210 - Python tracker

Benchmark on macOS Mojave (10.14.2), x86_64:

$ ./python.exe -m perf compare_to fork_exec.json posix_spawn.json 
Mean +- std dev: [fork_exec] 2.79 ms +- 0.06 ms -> [posix_spawn] 1.64 ms +- 0.03 ms: 1.70x faster (-41%)

The speedup is "only" 1.7x faster, it's less impressive. Maybe fork()+exec() is more efficient on macOS than on Linux.