Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Keyboard latency

danluu.com

Post reply on HN
Print view View original

141–150 of 274 posts

Re: Keyboard latency

#141

Post by kentt »

ilaksh wrote: post #136

This great article and the other recent one from him started me down the path of thinking about an end-to-end optimized modern computer and operating environment. If you _could_ (not saying it's easy or even necessarily practical at all) drop replace all of the slow stuff like high-latency keyboards, syscalls, CPU-GPU communication (i.e. effective HSA) and build some proof-of-concept operating environment (that was e…

I'm not sure if there's a common switch with less travel, but you could look into using spacer and/or landing pads to accomplish what you're looking for.

Re: Keyboard latency

#142

Post by cakebrewery »

skeleton wrote: post #130
pdkl95 wrote: post #92

Earlier quoted context omitted.

> strike a key less than 100 ms after some visual stimuli, I'm sure I couldn't do it The video game "Super Hexagon"[1] is a surprisingly interesting demonstration of this limitation, and how the mind tries to workaround the problem. The higher difficulties ("hexagonest"[2]) seem impossible at first. In the easier levels you can react , but now the time it takes to see the scree, parse the simple graphics, recognize t…

I finished that game a few years ago (was most definitely worth the 60 cents I paid for it). From what I recall, to finish the final level I was relying for the most part on 'muscle memory' in relation to the familiar patterns. I would visually interpret what kind of pattern it was, my position relative to the pattern and then there seemed to be a conscious disconnect to the actions I performed to get through the pat…

I am with you with the relative movements. Most of the faster songs are fun because they have triplets or alternating patterns that are easy to adapt to once you're used to the pattern.

As for the game you played, it must have been the DDR series. You can't "finish" Stepmania since it's an open source rhythm game where the community has created thousands and thousands of songs to to play.

Re: Keyboard latency

#143

Post by fred256 »

The experience of 100 ms latency is definitely noticeable. Ask anyone who's ever ssh'd to a server across a continent or ocean. Empirically, I notice I have a lot more typos in such a situation.

Re: Keyboard latency

#145

Post by pdkl95 »

BoppreH wrote: post #117
pdkl95 wrote: post #92

Earlier quoted context omitted.

> strike a key less than 100 ms after some visual stimuli, I'm sure I couldn't do it The video game "Super Hexagon"[1] is a surprisingly interesting demonstration of this limitation, and how the mind tries to workaround the problem. The higher difficulties ("hexagonest"[2]) seem impossible at first. In the easier levels you can react , but now the time it takes to see the scree, parse the simple graphics, recognize t…

This is also clear on rhythm games like Stepmania. Here's a random video from a keyboard user: https://youtu.be/TWiMnENdcyY?t=56 At this speed the player is reacting (and hitting with correct timing) about ten notes (arrows) per second. This is possible by memorizing and reacting to group patterns instead of individual notes, but more importantly, reacting unconsciously. A player can play at this level without consci…

A big difference between Hexagon and most other rhythm games like Stepmania, Beatmanias IIDX, Guitar Hero, etc, is that pattern is the same. Just like musicians memorize complex music that they later perform[1] with precise timing, the same is possible for these step/note patterns. I've personally seen someone perform one of the insane speed/note-density DDR songs blindfolded. Humans have surprisingly good internal timing and mechanical ability, iff you can memorize/practice it before hand.

Super Hexagon doesn't allow any of that. The game is randomly generated each time, making memorization impossible. It's 100% reaction against the incoming wall pattern, with no pauses. Except you don't actually have time to "react".

I recommend this[2] essay that does a much better (and more poetic) job of explaining how uniquely Supper Hexagon interacts with human perception.

[1] https://www.youtube.com/watch?v=JRUwpUqSFbI

[2] https://problemmachine.wordpress.com/2015/04/11/hexagon/

Re: Keyboard latency

#146

Post by ehsankia »

joebadmo wrote: post #104
ehsankia wrote: post #81

Earlier quoted context omitted.

Actual activation might be hard to get, but when the key bottoms out is probably the best way to go. Or even better, why not post both when key travel starts and when it ends. If people are really curious, they can model a linear scale and use the key response plot to guess exactly where the activation happens.

> when the key bottoms out is probably the best way to go I disagree. One of the greatest benefits of mechanical keyboards is that they actuate before bottoming out. With some practice you can learn to type without bottoming out, which can greatly increase your typing speed, and decrease the amount of stress on your fingers and wrists.

Sure, but the start and end value are the easiest ones to measure. As I alluded to, once you have the two extremes, you can the activation plot [1] to get the exact activation time. For the case of Cherry MX Blue, it would be at 62.5% between the start and end.

[1] https://i.stack.imgur.com/GzswL.png

Re: Keyboard latency

#147

Post by uxp »

DigitalJack wrote: post #138
xbkingx wrote: post #112

Earlier quoted context omitted.

I immediately switched to skeptic mode when I saw no actuation points or normalization for travel distance. All this is showing is that to move further it takes longer. Duh. Why even bother pointing out the polling rate? That's like setting up runners at random places on the racetrack to measure who's faster. The guy/gal that starts closest to the finish line isn't necessarily faster. I'm using Cherry MX Speed switch…

Do they spec the force in newtons? Without mass, g’s don’t really say much except as maybe a relative measure between things of the same mass.

'g' is gram-force. It's the weight required to "click" the switch over it's actuation point. 1 Gram is equivalent to 0.980665 centinewton, so for most measurements of keyboard switches, g's and cN's are used interchangeably.

Re: Keyboard latency

#148

Post by sundvor »

Splines wrote: post #73
sundvor wrote: post #48

Earlier quoted context omitted.

If you game on a mechanical keyboard, you've pretty much worked out exactly where the switch points are and will be working the keys in a fashion different to normal typing. So I'm not quite buying the way the measurements were made vs the purpose of the tests.

Do you really press every possible key down almost to the switch point, and then when you want to actuate the key, press it a tiny bit further? I would guess (and maybe I'm wrong about this) that you rest your fingers on the keycaps, and press them in as far as needed to actuate, but no further. The key still needs to travel.

I'm using Romer Gs now (G910 at home for a while, and recently the G413 at work), making the switch from MX Browns as I found them too heavy (programming RSI).

Not sure how much I press them down (will try to analyse at next opportunity), but whenever I play a FPS (which is admittedly nowhere as often as I'd like these days) I certainly "preload" the fingers on the WASD keys in such a manner that the press is far quicker than when I touch type.

Precision and responsiveness is far better than using a chiclet type keyboard such as the MS Sculpt, which compares a bit to the Apple Macbook keyboards from memory (although the new Macbook Pro has even shorter travel again). The Sculpt (or MBP) has much shorter overall travel compared to the Romers, but the feel of when you are off/on really doesn't compare; the keys feel dead in comparison for gaming. YMMV.

Re: Keyboard latency

#149

Post by skeleton »

cakebrewery wrote: post #142
skeleton wrote: post #130

Earlier quoted context omitted.

I finished that game a few years ago (was most definitely worth the 60 cents I paid for it). From what I recall, to finish the final level I was relying for the most part on 'muscle memory' in relation to the familiar patterns. I would visually interpret what kind of pattern it was, my position relative to the pattern and then there seemed to be a conscious disconnect to the actions I performed to get through the pat…

I am with you with the relative movements. Most of the faster songs are fun because they have triplets or alternating patterns that are easy to adapt to once you're used to the pattern. As for the game you played, it must have been the DDR series. You can't "finish" Stepmania since it's an open source rhythm game where the community has created thousands and thousands of songs to to play.

I was replying to the comment on Super Hexagon. I believe the concepts that allow us to perform these feats are the same however.

Re: Keyboard latency

#150

Post by WalterSear »

colanderman wrote: post #9

I'm surprised the "humans don't notice 100 ms" argument is even made. That's trivially debunkable with a simple blind A/B test at the command line using `sleep 0.1` with and without `sleep` aliased to `true`. To my eyes, the delay is obvious at 100 ms, noticeable at 50 ms, barely perceptible at 20 ms, and unnoticeable at 10 ms. Not to mention that 100 ms is musically a 16th note at 150 bpm. Being off by a 16th note e…

I can very quickly tell the difference between 10ms and 5ms, when playing a musical instrument.
Post reply on HN