I've long wondered why some terminals and operating systems felt like they were pretty laggy. In the sense that if I press my character to move, how long until they actually move?
iTerm2 on MacOS is worst offender. But I can't tell if it's iTerm2 or MacOS itself. I remember trying other terminals on Mac, and it was mostly the same. iTerm2 itself also had bunch of rendering options, but I couldn't get them to do anything I could actually feel affected input lag. One thought I had was: maybe iTerm2 added 1 frame lateness, and MacOS itself added another? But that would be ~30ms on a 60fps monitor which I can easily already tell on a server-connection NetHack.
I also have no idea if measuring "N frames late" is actually a sensible way to think about this. I assume computers know when a key is pressed at a higher frequency?
Linux xterm and rxvt were the fastest that I remember, on X11 (I've never used Wayland like in the article, well not for NetHack anyway).
I have no idea how compositors work on any of these operating systems or X11/Wayland to say anything smart about them or why they would be slower or faster.
Reading the article...I realized I have that same iPhone 15 Pro with 240fps recording. I could replicate that experiment, but testing out terminals on various operating systems instead I used to play on. So I could now test if my gut feeling was right all along or not. or maybe it lied to me all these years.
I wrote the idea in the article down on my notes, maybe when I'm bored enough I'll try it :) and I can stop saying propaganda about iTerm2 being slow if it turns out I was completely wrong. Maybe I have easier time because all my NetHack days were 60fps, so I have more leeway in measurements.
I'm not active in NetHack playing anymore, although I sometimes play it as a comfort game.