#video #lecture by John #Ousterhout about how his new RPC protocol #Homa improves tail #latency compared to TCP/IP and RDMA (RoCE)
on 02026-09-22trying to popularize #responsivity and teach people about #latency: “You’ve probably come across a website where scrolling stutters now and then, a button responds slightly late, or the letters you type into a search box show up half a beat behind. It isn’t bad enough to be annoying, but it gets on your nerves in a subtle way. That kind of jank is what a blocked main thread looks like. (...) web performance metrics. INP (Interaction to Next Paint), which measures how long it takes for the screen to respond after the user does something, and TBT (Total Blocking Time), which measures the total time the main thread was blocked during page load”
Includes details that I didn’t know about setTimeout and something called MessageChannel in #JS. Doesn’t mention web workers, though.
#apenwarr’s "blip" for measuring your internet connection #latency and quality
on 02026-05-27using #zram vs. #zswap to get better UI #latency in #Linux. #Fedora eliminated disk-based swap by default. #toread
on 02025-11-05#video on video driver regression #testing in #videogames and #latency (“microstuttering” and “hitching”) on Linux. No, on Windows (10? 11?) due to mtkwecx, the MediaTek integrated Wi-Fi/Bluetooth hardware driver, which also causes replugging the keyboard and mouse to not work. Disabling the hardware in the BIOS solves the problem. So does downloading an updated driver from ASRock, but only for the keyboard/mouse problem.
on 02025-09-03Little’s Law (L=λW) from queuing theory, and service #latency
on 02025-07-22#video of John #Carmack saying video games, even Atari, are nowhere close to being solved by #neural-networks yet, which is why he’s doing Keen Technologies. They’re going to open-source their RL agent! Which they’re demoing playing an Atari 2600 (emulated on a Raspberry Pi) with an Atari 2600 joystick and servos (“Robotroller”), running on just a gamer laptop with a 4090. (No video of the demo, though, just talking head and slides.) He says now he’s using PyTorch just like anyone else instead of implementing his own matrix multiplies. Mentions that the Atari screen is 160×210, which I’d forgotten. They’re using April-tag fiducials so their camera can find the screen, but patch them into the video feed instead of trying to get the lighting right for stickers. He says the motion-to-photons #latency at Oculus had to be below 20ms for avoiding nausea (26'58"). Finding the Atari scores on the screen was surprisingly hard. #retrocomputing #AI
on 02025-07-09#video on the lunar lander #Resilience, which died because the laser rangefinders it was relying on experienced unexpected #latency. #space
on 02025-06-17#video from May 19: #interview with #drones developer Sergey Tovkach from #Russia on how #weaponry from #Ukraine is far better than what the US and even China have, and now 70% of fatalities on the battlefield are from drones. “A special thanks to our Western partners, because where else could we have trained on so much of your equipment? You delivered it straight to the front, and we got to study it up close. We learned all the weak points. We learned exactly where to strike. (...) There isn’t a single Western drone that’s proven itself effective in this conflict.” He claims #China makes military gear that doesn’t survive being tossed out of a truck, “like toys”. Ukraine barely uses Chinese chips in their drones, but Russia’s have to be all Chinese. Talks about mine-laying drones (“in use for about a year and a half now”), “sleeper/ambush drones” (same time frame, Ukrainians first — drones playing possum, pretending to be “a real trophy”), and drones dropping caltrops welded from rebar. “Same [ambush tactics] with drones placed on rooftops or hilltops overlooking roads (...) when the vehicles come, the drone just takes off, flies a short distance, and hits its target. That whole tactic really took off with the rise of fiber optic drones,” because they don’t need to burn 5–10W to transmit the video feed. Russian operators now wind up used fiber-optic cables on a cordless drill to avoid giving away their position. “The Orbit [Russian remote piloting] system. (...) The Ukrainians have been using radio relays and internet bridges for a long time already. (...) #Starlink is the holy grail. (...) Take away Starlink and Ukraine’s entire fleet of naval drones disappears overnight. (...) Why doesn’t Russia have naval drones? Well, we do have the boats and, but we don’t have Starlink.” But he says Starlink’s #latency is too high for FPV drone piloting. Baba Yaga or “Vampire” drones dropping antitank mines with 6–8kg of TNT have been very effective; Russia is ramping up two factories to produce its own equivalent.
on 02025-06-17John #Carmack on a style of programming where you inline all your code and do not use any subroutines. “As an additional confirmation of the point of the article, a couple years later when I was working on the Doom 3 BFG edition release, the exactly predicted off-by-one-frame-of-latency input sampling happened, and very nearly shipped. That was a cold-sweat moment for me: after all of my harping about latency and responsiveness, I almost shipped a title with a completely unnecessary frame of latency.” #latency #real-time #responsivity #games #video-games #software-design
on 02024-09-03#latency on #STM32 #radio #hardware
on 02024-02-10#Luu on end-to-end input #latency, from when the key starts moving to when a letter appears on the screen, with results from 30ms (Apple //e) to 300ms, with most modern computers around 100ms. Also, scrolling (30ms–860ms, mostly around 140ms). And he explains why this matters for #UX.
on 02021-06-05#Luu on keyboard #latency, finding 15ms to 60ms in the keyboard itself (from when the key starts moving to when the USB packet finishes); no advantage to “gaming” #keyboards. #UX
on 02021-06-05#Carmack on why #VR #latency shouldn’t exceed 20 ms. #UX
on 02021-06-05#latency in #VR shouldn’t exceed 20 ms. #UX
on 02021-06-05#Abrash on how acceptable #latency in #VR was unattainable at the time. #UX
on 02021-06-05“Two-handed interaction on a tablet display” from 2004; Ping hacked together a limited #multitouch screen (though with much better user interface #latency than most modern displays, about two frames at 29.97 fps — 70 ms) and made a 3'30" video of possible #UX techniques.
on 02017-12-31John Carmack on #latency (won’t load)
on 02017-08-06On rendering #latency. Apparently 1000fps cameras only cost €115 now?
on 02017-08-06Dan Luu complains that many commonly-used terminal emulators have painfully high #latency. #UX
on 02017-07-23#audio #latency on #android has an extra 10ms
on 02015-11-25