Terminal and shell performance

iTerm2 author here. I'll spend some time looking into iTerm2's latency. I'm sure there are some low-hanging fruit here. But there have also been a handful of complaints that latency was too low—when you hit return at the shell prompt, the next frame drawn should include the next shell prompt, not the cursor on the next line before the new shell prompt has been read. So it's tricky to get right, especially considering how slow macOS's text drawing is. If…

As a keyboard player, I can tell you that anything over 10ms latency noticeably degrades the experience. 100ms of keypress-to-sound latency makes the instrument unplayable. Your ears will detect very small latencies; offset something just by 1-2ms, and you get an echo feel; 50ms will be off-beat. (Organ players have to deal with that kind of latency on their instrument[1], but it's a hard skill to learn, and limits the music that can be performed on the instrument. Say, following…

The bad news is the defaults on modern platforms are often very bad for latency. The good news is that it is possible to achieve good latency on most modern systems with a lot of attention to detail. With good hardware and good software it is even possible to e.g. run console emulators with lower latency than they would have on original hardware connected to a CRT. I just wrote a three part series detailing a lot of ways to…