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Comment by vladvasiliu | Hacker News Reader

> ... and not to mention it's one of the slowest (yes! contrary to what they blowhard they response time to keys is very large) terminals out there.

This is intriguing to me. You're not the first I've seen complaining about this, so there must be something to it.

But in my case, on a fairly low-end machine, what I type shows up instantaneously[0] on the screen, even when the CPU is busy compiling.

I'm running an i5-6500 with integrated hd 530 graphics and a 4K screen. I use i3 (so X11) and Picom with a bunch of effects.

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[0] I have a mechanical keyboard, and if I push the key all the way down, I hear the sound of the key bottoming out after I see the character on the screen.

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Nothing with computers is instantaneous. I strongly suspect that there is at least 15ms of latency in your setup, and probably much more. Different people have different sensitivity to latency, just because you don't notice it doesn't mean it isn't there.

Well, you're right, technically. But in that case, all terminal applications have latency, so is your point that the parent's complaint is unfounded?

In these kinds of discussions, the talk is usually about perceived latency not absolute latency. If it feels like there's basically none, then it's good enough. It doesn't mean there's absolutely 0.0 ns latency.

> Different people have different sensitivity to latency

This I can get behind. But I doubt that what seems instantaneous to me would seem "terribly long a time" to someone else, especially since I look specifically for this. As you pointed out, no terminal app has absolute 0 latency, so if one particular software has terrible latency compared to another one, the difference would have to be pretty huge.

Do note that I'm not talking about being bothered by the latency. I know a lot of people who will notice the latency when pointed out to them, but they don't really care. Personally, I hate when things lag, even if I may happen to have a worse perception than average (don't actually know if that's the case).

> But in that case, all terminal applications have latency, so is your point that the parent's complaint is unfounded?

All terminals have latency, but that doesn't mean that all terminals have equal latency. Point was that anecdotes about subjective instantaneity are pretty meaningless, especially without any reference point.

It would be much more meaningful to substantiate the discussion with actual data; the measurements done by danluu are one example https://danluu.com/term-latency/

Of course there can be quibbles about the specific methodology, but its still much better than having no data at all. Especially for something that is as measurable as latency is.

In general if you claim something is fast, back that claim up with some numbers.

Some applications using OpenGL or Vulkan and Wayland compositing end up with latency related to one or two frames of the screen refresh. Which means that characters appear onscreen much faster on a 144 or 240 Hz display.

Not really a surprise but something to be aware of.

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