4 ms·

That's the thing, there isn't a link between latency and throughput in a pipe. TCP is not exactly a pipe. It's sending a message and waiting to receive a confi

That's the thing, there isn't a link between latency and throughput in a pipe. TCP is not exactly a pipe. It's sending a message and waiting to receive a confirmation back before sending more. It's control logic to control the flow in a pair of pipes, that's affected by the latency back and forth. UDP doesn't do that. The Ethernet link doesn't do that. The HDMI link to a TV doesn't do that.

Terretta 6y ago
If you're still writing to enlighten readers, this last information may risk losing them, as it's no longer relevant to their real world experience. In their real world experience, these are linked, as the control logic you acknowledge is affected by latency impacts their download, which is over TCP/IP. But this is a diversion, as I was not attempting the make that connection. I was relating the size of 15 ms and 100 ms to an experience where people can perceive those intervals. If, by contrast, you're showing me you understand this, sounds like you do. We had developed an internal tool before Aspera's FASP[1], for our clients to deliver us video, and us to distribute content among hubs at scale, at speeds that saturated links. Understanding the mechanics and limiting factors of information propagation was necessary to be on that team. Turns out most devs don't have a great grip on the physics -- in the most common mental model, everything happens instantly. And so things get slow. 1. https://en.wikipedia.org/wiki/Fast_and_Secure_Protocol https://en.wikipedia.org/wiki/Fast_and_Secure_Protocol
- user5994461 6y ago
  Well, we went from video games to TV to TCP. That's quite a lot of different things, no wonder we lost people on the way. =) There is one thing I'd like to insist on though, I'm not sure whether people could actually notice 100 ms of latency after user input. You assume that users do? but I don't think they necessarily do. I think the full delay between when you press a button on a gamepad and when the frame changes on the TV is somewhere around that and gaming consoles are generally considered very usable. (Of course latency in computer networks is a different matter). My daily job among other things is to optimize software and networking infrastructure covering 4 continents and 50 datacenters. I'd say I have a certain grasp of networking. ;)
  - Terretta 6y ago
    It's been 12 days since our last confession, but this Verge review of the Xbox Series X touches on this notion of whether people notice or 'feel' input lag, tied to frame rates (and the interval between them): This is where the Xbox Series X really started to feel even more PC-like to me. I play at 165Hz with frame rates that exceed 200fps in games like Destiny 2, Valorant, Call of Duty: Warzone, and CS:GO on my gaming PC. I do this a lot of the time by dropping a lot of the quality settings lower because I personally value frame rates over visual quality. Running around the versus multiplayer mode in Gears 5 in 120Hz felt like I was playing on my PC. With frame rates hitting 120fps, input lag is reduced, and the experience was suddenly so much smoother than what I’ve ever experienced on an Xbox One X. That same feeling of PC-like smoothness plays out in Dirt 5 with the 120Hz mode enabled. Sure, the game drops to rendering at 1440p and some of the visual quality is lowered to achieve 120fps, but when I’m sliding around corners and the input latency is reduced, it’s far better than some mud and snow rendering just that little better on my 4K TV to the point I probably wouldn’t notice the difference. It’s that feeling that’s really important with this new Xbox, and I can’t stress it enough. -- https://www.theverge.com/2020/10/15/21515790/xbox-series-x-preview-hardware-games-performance?scrolla=5eb6d68b7fedc32c19ef33b4 https://www.theverge.com/2020/10/15/21515790/xbox-series-x-p...

Terretta 6y ago

If you're still writing to enlighten readers, this last information may risk losing them, as it's no longer relevant to their real world experience. In their real world experience, these are linked, as the control logic you acknowledge is affected by latency impacts their download, which is over TCP/IP. But this is a diversion, as I was not attempting the make that connection. I was relating the size of 15 ms and 100 ms to an experience where people can perceive those intervals. If, by contrast, you're showing me you understand this, sounds like you do. We had developed an internal tool before Aspera's FASP[1], for our clients to deliver us video, and us to distribute content among hubs at scale, at speeds that saturated links. Understanding the mechanics and limiting factors of information propagation was necessary to be on that team. Turns out most devs don't have a great grip on the physics -- in the most common mental model, everything happens instantly. And so things get slow. 1. https://en.wikipedia.org/wiki/Fast_and_Secure_Protocol https://en.wikipedia.org/wiki/Fast_and_Secure_Protocol

user5994461 6y ago
Well, we went from video games to TV to TCP. That's quite a lot of different things, no wonder we lost people on the way. =) There is one thing I'd like to insist on though, I'm not sure whether people could actually notice 100 ms of latency after user input. You assume that users do? but I don't think they necessarily do. I think the full delay between when you press a button on a gamepad and when the frame changes on the TV is somewhere around that and gaming consoles are generally considered very usable. (Of course latency in computer networks is a different matter). My daily job among other things is to optimize software and networking infrastructure covering 4 continents and 50 datacenters. I'd say I have a certain grasp of networking. ;)
- Terretta 6y ago
  It's been 12 days since our last confession, but this Verge review of the Xbox Series X touches on this notion of whether people notice or 'feel' input lag, tied to frame rates (and the interval between them): This is where the Xbox Series X really started to feel even more PC-like to me. I play at 165Hz with frame rates that exceed 200fps in games like Destiny 2, Valorant, Call of Duty: Warzone, and CS:GO on my gaming PC. I do this a lot of the time by dropping a lot of the quality settings lower because I personally value frame rates over visual quality. Running around the versus multiplayer mode in Gears 5 in 120Hz felt like I was playing on my PC. With frame rates hitting 120fps, input lag is reduced, and the experience was suddenly so much smoother than what I’ve ever experienced on an Xbox One X. That same feeling of PC-like smoothness plays out in Dirt 5 with the 120Hz mode enabled. Sure, the game drops to rendering at 1440p and some of the visual quality is lowered to achieve 120fps, but when I’m sliding around corners and the input latency is reduced, it’s far better than some mud and snow rendering just that little better on my 4K TV to the point I probably wouldn’t notice the difference. It’s that feeling that’s really important with this new Xbox, and I can’t stress it enough. -- https://www.theverge.com/2020/10/15/21515790/xbox-series-x-preview-hardware-games-performance?scrolla=5eb6d68b7fedc32c19ef33b4 https://www.theverge.com/2020/10/15/21515790/xbox-series-x-p...