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Typometer: A tool to measure and analyze the visual latency of text editors

pavelfatin.com

41–50 of 104 posts

Re: Typometer: A tool to measure and analyze the visual latency of text editors

#41
post #40

Correct me if I'm wrong, but this doesn't seem to measure input stack latency nor how long it takes for the pixels to be actually visible on the display after all of the compositing delays. All this measures seems to be time from injected keyboard event until pixels change on whatever bitmap/surface in memory. Message passing, in other words.

That sounds like it's measuring almost exactly the portion of the end-to-end latency that an application can actually do anything to reduce; the rest is in hardware and drivers. So it would definitely be a useful measure, but cutting this measured latency in half won't cut the entire end-to-end latency in half.

Re: Typometer: A tool to measure and analyze the visual latency of text editors

#42
post #8

Earlier quoted context omitted.

Gui Emacs via tramp+ssh is awesome. Terminal Emacs over ssh is, well, just like anything else in a terminal over ssh. Can't say I notice the latency unless the datacenter is on the other side of the country.

Isnt it the same if you use tramp in the terminal, assuming you are running emacs locally and tramping into the server to edit?

Sure, although in that case why not use the GUI?

Re: Typometer: A tool to measure and analyze the visual latency of text editors

#44

The companion article at https://pavelfatin.com/typing-with-pleasure/ has some example results, showing Atom, the only Electron-based one in the list, as having several times more latency than the others. I wonder how VSCode compares. It's unfortunate that software seems to feel slower the newer it is, including developer tools such as text editors/IDEs. I suspect this is because most people - including younger devel…

I also can't be the only one annoyed by the input lag in the windows login screen and start menu search. Somehow both of them seem to think it's fine to just ignore keypresses for half a second before doing anything. Annoyance aside I seriously worry about the accessibility of the windows lock screen. Through a weird display setup I sometimes find myself trying to log in blind and I just can't do it. There seems to b…

The login screen one is particularly ridiculous, because my Ubuntu machine takes about as long to wake up as my Windows, but it sensibly buffers the keypresses until it can insert them so I never mistype.

It's just glaringly obvious that nobody has bothered for even a second to think about how to solve the problem (or indeed, just copied the solution that already exists elsewhere).

The start menu on the other hand I gave up on several years ago. I don't know what's in it anymore, and I don't care, because nothing could be worth the >5s wait for it to open.

Re: Typometer: A tool to measure and analyze the visual latency of text editors

#45
post #32
post #16

Earlier quoted context omitted.

A few months ago I found my old GameBoy and played through part of "Kirby: Nightmare in Dreamland". I know its not the most well-known game, so the relevant detail is that it relies a lot on timing and quick movements. I was completely blown away by the responsiveness of the controls. The control feedback was instant , frames were rock-solid, and there were no loading screens at all. When I put down the game, I was j…

It really amazing playing with old technology. In Super Mario Bros on the NES, when you press the jump button Mario jumps the very next frame. And with a CRT you get instant response time. You just can't get that responsiveness anymore.

Wait, why would a CRT be faster than LCD? If anything, I'd naively expect faster response with no electron beam to move.

Re: Typometer: A tool to measure and analyze the visual latency of text editors

#46
post #41
post #40

Correct me if I'm wrong, but this doesn't seem to measure input stack latency nor how long it takes for the pixels to be actually visible on the display after all of the compositing delays. All this measures seems to be time from injected keyboard event until pixels change on whatever bitmap/surface in memory. Message passing, in other words.

That sounds like it's measuring almost exactly the portion of the end-to-end latency that an application can actually do anything to reduce; the rest is in hardware and drivers. So it would definitely be a useful measure, but cutting this measured latency in half won't cut the entire end-to-end latency in half.

Application might be able to make choices about APIs that affect output latency. Hardware swap chain (AKA multi-plane overlay) is going to be visible on the screen at least one full vsync faster than something that's composited on a frame buffer. In the best case, this measuring method wouldn't see any difference in such case. In the worst case reading pixels from the screen might even misleadingly measure worse due to triggering a corner case code path in the window compositor.

Using an emulated legacy API (like Windows GDI) might yield a very low latency score in this test, even though it might take much longer to actually be visible on the display.

Re: Typometer: A tool to measure and analyze the visual latency of text editors

#47
post #32

Earlier quoted context omitted.

It really amazing playing with old technology. In Super Mario Bros on the NES, when you press the jump button Mario jumps the very next frame. And with a CRT you get instant response time. You just can't get that responsiveness anymore.

Wait, why would a CRT be faster than LCD? If anything, I'd naively expect faster response with no electron beam to move.

The NES-CRT connection is analog and the screen is drawn line by line, if you connect a digital monitor that will have to be buffered and you get some delay/lag of min 1 frame.

Re: Typometer: A tool to measure and analyze the visual latency of text editors

#48
post #32
post #16

Earlier quoted context omitted.

A few months ago I found my old GameBoy and played through part of "Kirby: Nightmare in Dreamland". I know its not the most well-known game, so the relevant detail is that it relies a lot on timing and quick movements. I was completely blown away by the responsiveness of the controls. The control feedback was instant , frames were rock-solid, and there were no loading screens at all. When I put down the game, I was j…

It really amazing playing with old technology. In Super Mario Bros on the NES, when you press the jump button Mario jumps the very next frame. And with a CRT you get instant response time. You just can't get that responsiveness anymore.

How does that compare to 144hz 1ms response gaming monitors? I know that late CRT’s handily beat early flatscreens but does that still hold?

Re: Typometer: A tool to measure and analyze the visual latency of text editors

#49

I'm all for faster software, but input lag measurements need to be put in perspective. Just because an editor can process an input in 3ms doesn't mean the pixels will change on your screen in 3ms. If you're using a 60Hz monitor, you're only going to see new frames every 17ms at most (1 second / 60Hz). Your graphics pipeline might have some additional buffering, adding 10s of milliseconds of lag. Your monitor likely h…

I don't agree with this at all. If the software doesn't care to make keypresses responsive how does this philosophy translate to anything more complicated than reading and rendering the result of these keystrokes? The answer is pretty obvious if you try any of the slower editors pointed out in the article (or pretty much 90% of software written in the last decade). It doesn't take a person with sensory hypersensitivity to pick up on the differences.

Re: Typometer: A tool to measure and analyze the visual latency of text editors

#50

Earlier quoted context omitted.

Fair enough, but on a screen who's sole purpose is to let me type in my password I really shouldn't require a Narrator to find the one and only input field. It's nice that the problem has a solution, but it shouldn't have been a problem to begin with.

The trouble is that this screen isn't just for entering your password. On my logon screen, I have not only the PIN field (because I enabled the TPM-based Windows Hello feature), but also these other links or buttons: "I forgot my PIN", "Sign-in options", network, Ease of Access, and power. So use of a full GUI framework, that supports accessibility tools such as a screen reader, is justified.

The user doesn't care about any of that. I should be able to wake up the box by typing the pin. The reality is that i have to press the first letter of it then wait then press it again and then I have to wait and see if a dot appears in the field.

The reason it works like this is that the user is forced to use the software. It should be the other way around. If people are forced to use something developers should do what they can to not make the experience incredibly annoying.

Sure, there can be situations where you need to cut corners but this is the log in screen.

After logging in I mistype an application name in the search box and wait for the dialog to pop up that says "Best matches" with an empty list under it. It can't even find "tunderbird"

If I type a single letter it shows "search teh web for "a".

But it does show Atom! Woah! Technology at work!

I get to chose, I can press the down arrow and select "apps" then press enter twice OR I can press the down arrow twice and press enter! Becareful! Dont press the arrow to fast or it jumps back to searching the web for "a".

No one put any thought into this process.

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