Latency becomes more relevant the less you are able to muscle-memory your way through an input. Audio apps often need relatively short latencies(<5ms is considered professionally useful) because musicians are hearing, responding and adjusting to match time, so when they do something and the delay on output is perceptible, their timing starts to oscillate.
On the other hand, if I'm drawing on a graphics tablet, and I've trained up some muscle memory skills with blind contour exercises, I don't care that much about application latency because I'm using the tactile feedback to know what the pen is doing. I only have to look to see where the cursor starts, everything else is minor adjustment.
Keyboarding is also definitely more on the muscle-memory end of the spectrum: you look to see errors, but you can generally type a whole password without seeing it, once you've practiced.
Sure, but the article isn't about audio apps or drawing with a graphics tablet; it's about typing delay in terminal emulators.
I have to agree with the OP here. I've used urxvt almost every day for years (I remember using it on a laptop with 32 MB of memory), and have never once had a problem with typing latency. I didn't even realize it was a thing people bothered to measure until I saw this article.
there's always someone in these threads who says something like this, and to be honest https://danluu.com/keyboard-latency/#does-keyboard-latency-m... could benefit from a stronger argument that latency impedes performance or pleasure specifically for keyboard tasks rather than touchscreen or stylus tasks
I can only offer anecdote and no concrete measurements. But I've used bad terminal emulators and good ones, and I can really notice the difference. When the letters appear even a few frames after they should, there's a definite (if mild) feeling of discomfort. Like some kind of sensory-motor "friction". I can still get work done, but I'm just a little less happy.
There was another HN thread recently where this topic came up, I posted about the human nervous system as a prediction-feedback system where we should expect even small latencies to have a bad effect. And someone replied with the interesting insight that 10-100ms latency feels like "you are using the tool", while <10ms latency feels like "the tool is an extension of your body". (I'd quote the whole thing but I think there's an HN rule against that.)
I'd certainly like to see an experiment where typing latency could be controlled artificially, on a high refresh rate monitor. It would test what level of latency/jitter has a perceptible effect on objective typing error rates, and subjective ratings of "satisfaction". Ask them to compare two text input fields where one has more latency than the other, see what degrees of difference are noticeable, to determine the "resolution" of time perception for fine motor tasks. I would wager that for good typists the "threshold of perceptibility" is as low as 10ms, and perhaps even lower. But that's based on my own intuition and experience; I'd love to know for sure.
> 10-100ms latency feels like "you are using the tool", while <10ms latency feels like "the tool is an extension of your body".
Seems like that's similar to how Vim can feel so smooth to use, with experienced users not even thinking about what keys to press but just what operation to do, as the inputs can be combined in intuitive ways and the entire program has very low latency to do anything. Very different from "ugh, now I again need to move my hand to the mouse to select that bit of text".
my intuition matches yours (and luu's) but that isn't the same kind of conclusive refutation as luu's generic input latency arguments https://danluu.com/input-lag/
i mean it isn't going to convince anyone who says they 'have never once had a problem with typing latency'
On the other hand, if I'm drawing on a graphics tablet, and I've trained up some muscle memory skills with blind contour exercises, I don't care that much about application latency because I'm using the tactile feedback to know what the pen is doing. I only have to look to see where the cursor starts, everything else is minor adjustment.
Keyboarding is also definitely more on the muscle-memory end of the spectrum: you look to see errors, but you can generally type a whole password without seeing it, once you've practiced.