I ran across this when I found samply [0], a CLI sampling profiler. On samply's GitHub there's a link to a sample profile that opens in the Firefox Profiler and I was in awe at just
how fast it is! Try dragging your mouse over the timeline for a second.
Demo: https://share.firefox.dev/3j3PJoK
Firefox Profiler: https://github.com/firefox-devtools/profiler
0: https://github.com/mstange/samply