4 ms·
> What really confuses me is the definition of "low-latency" nowadays There has never been a strict definition of “low latency”. It is heavily context-dependen
by jacobolus 8y ago
> What really confuses me is the definition of "low-latency" nowadays
There has never been a strict definition of “low latency”. It is heavily context-dependent. Something which is not “low latency” enough for live audio or a car’s steering controller might be plenty fast for an internet text chat service.
- gpderetta 8y agoA better term is soft or hard real-time.
- baragiola 8y agoThat's been the case for operating systems and it's quite effective
- zokier 8y agoWhile not completely orthogonal, I feel like real-time (soft or hard) is distinct from low latency; real-time can be still relatively high-latency as long as the latency is bounded/controlled/predictable. Of course generally in practice real-time systems strive to have low latency too.
- jacobush 8y agoAbsolutely. Think about turning a super tanker or something other huge. It must happen on time. It doesn't matter if it takes one or two seconds to initiate.
- true_religion 8y agoI thought the difference between soft vs hard realtime wasn't one of magnitude, but context. Soft: After X time, usability of the data degrades with age. Hard: After X time, the data is useless (example: realtime car control systems; if you take too long the car has already crashed)
- gpderetta 8y agoOh, sorry, I mean that low latency is a synonym of real-time, either hard or soft depending on the application.
- TickleSteve 8y agoIts related, but not equivalent. real-time == "bounded latency" (to a soft or hard degree). low-latency implies no threshold, just low relative to something else.
- spamizbad 8y agoNot exactly. Hard Real-Time = Missing a deadline is a major system fault. Hard read-time would be anti-lock breaks on your car: Did the cylinder not actuate within a given deadline? If so, disable the ABS feature system since its no longer deterministic, set an error code on the car's computer, and make some error light on the dashboard go on. Soft real time is video decoding: We need to render 1 frame every 1/30th-ish per second. If we miss our deadline, we either need to skip that frame and move onto the next, or pause to fill a buffer. You can have a hard real time system where the latency required is measured in seconds and a soft realtime system where the deadline is in nanoseconds.
- CoolGuySteve 8y agoSomeone at Google once told me they worked on “real-time” search. Having come from graphics and video rendering I asked what that meant and she said it was how search may or may not respond to key presses. Whatever it was, it certainly wasn’t real-time.