5 ms·
Just for fun I did film some video footage from my 60Hz monitor to see how quickly my terminal starts up. Seems like 2-3 frames to show up the terminal window,
by zokier 2y ago
Just for fun I did film some video footage from my 60Hz monitor to see how quickly my terminal starts up. Seems like 2-3 frames to show up the terminal window, and 1-2 frames to show shell prompt. So 50 ms - 83 ms. This is with foot terminal on Sway.
My very unscientific methodology was to run
$ echo hello && foot
in a terminal and measure the time between the hello text appearing and the new window appearing. Looking at my video, the time from physical key press to "hello" text appearing might be 20ish ms but that is less clear, so about 100 ms total from key press to shell prompt.
This is pretty much completely untuned setup, I haven't done any tweaks to improve the figures. Enabling foot server might shave some milliseconds, but tbh I don't feel that's necessary.
It'd be fun to do this with better camera, and also with better monitors. Idk how difficult it would be to mod in some LED to keyboard to capture the exact moment the key is activated, just trying to eyeball the key movement is not very precise.
- SushiHippie 2y agoWouldn't it make more sense to screen record with wf-recorder instead of a video camera?
- zokier 2y agoIn the end click-to-photon latency is what matters, so measuring the whole system end to end is good starting point, and that means video camera pointing at screen. Something like wf-recoder sees only part of the whole pipeline. How much latency is there between compositor copying frame to wf-recorder and same frame getting pushed physically out on the display cable? Without knowing exactly how the whole system is built such question is difficult to answer. But you also have to account for the fact that wf-recorder might interfere with the results, capturing screen is not free, and it might even push some part of the pipeline to less optimal paths. With video camera you can be fairly confident that measuring isn't interfering with anything.
- SushiHippie 2y agoMhm makes sense, maybe something like a capture card with a high refresh rate would be the best option, as it won't interfere with the OS, and eliminates the delay between your camera capturing a frame and your monitor refresh rate.
- zokier 2y agoSure high-speed capture card could be nice. But when many smartphones can do high-speed video, some even 960 fps, then that is very convenient (and low-cost) solution.