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How “latency numbers everybody should know” decreased from 1990–2020
171–180 of 225 posts
Re: How “latency numbers everybody should know” decreased from 1990–2020
#172Not an intuitive thing but the data is fascinating. A couple of notes of people who are confused by it: 1) The 'ns' next to the box is a graph legend not a data label (normally that would be in a box labeled legend to distinguish it from graph data) 2) The weird box and rectangle thing on the top is a slider, I didn't notice that until I was looking at the code and said "what slider?" 3) The only changes from 2005 to…
While the numbers may not be absolutely correct as stated in other comments, on a relative terms the conclusion from the trend is the same.
SSD was the biggest upgrade in performance in the past 15 years. There are still lots of system running on old HDD.
And the chart shows why I have been calling attention to latency computing for 10+ years. I hope the next stage is to reduce latency from Input, from keyboard to touch screen, and display input, and the actual display panel itself. On a 120hz screen even if you assume zero latency in everything else you still have a minimal of 8.3ms delay. Which is still quite obvious [1] once you put things in motion. And I think it is so hard there is enough room for at least another 10 years of hardware improvement.
[1] Applied Sciences Group: High Performance Touch
Re: How “latency numbers everybody should know” decreased from 1990–2020
#173Earlier quoted context omitted.
> If a laptop could play games at the quality of a top end PC today, would people really want to pay for an external streaming service, deal with latency, etc just so they can get the last 1% of graphical improvements? Think of it a different direction: if/when cloud rendering AAA graphics is practical, you can get a very low friction Netflix like experience where you just sit down and go.
IMO the service of netflix is the content library and not the fact it's streaming. If the entire show downloaded before playing, it would only be mildly less convenient than streaming it. But I don't think the streaming adds that much convenience to gaming. If your internet is slow enough that downloading the game beforehand is a pain, then streaming is totally out of the question. And gaming is way way less tolerant…
I'd (gently) say you may be generalizing your own behavior too much. I often just have say 45 minutes to kill and will just browse Netflix to find something to start immediately. Having to wait for a download would send me to something else most likely. Since COVID started, one thing I've heard repeatedly from friends with kids is they manage to carve out an hour or such for a gaming session, sit down, and then have to wait through a mandatory update that ends up killing much of their gaming session. Now add to that the popularity of game pass, and the possibility that "cloud console" offers something similar... there's plenty of people that would love that service imo.
Re: How “latency numbers everybody should know” decreased from 1990–2020
#174Not an intuitive thing but the data is fascinating. A couple of notes of people who are confused by it: 1) The 'ns' next to the box is a graph legend not a data label (normally that would be in a box labeled legend to distinguish it from graph data) 2) The weird box and rectangle thing on the top is a slider, I didn't notice that until I was looking at the code and said "what slider?" 3) The only changes from 2005 to…
It also tells us that the speed of light has not increased. (well, speed of signal on a PCB track is roughly 2/3 light and determined by the transmission line geometry and the dielectric constant, but you all knew that)
And Speed of light within Glass. We could still get that 1/3 back when we could somehow make ultra long distance hollow cable. We could get that Packet round trip from 150ms to 100ms.
But I dont think hollow cable are anywhere close to commercial launch.
Re: How “latency numbers everybody should know” decreased from 1990–2020
#175Earlier quoted context omitted.
"Packet roundtrip CA to Netherlands"
No, at the speed of light 150 ms is about long enough to send a packet from SF to Amsterdam and then send the reply back the long way around the entire rest of the planet.
Re: How “latency numbers everybody should know” decreased from 1990–2020
#176Complete laggard questions: * Did SSD exist in 1993? * Why using an "approximately equal" sign (as opposed to a real = sign) between e.g. 1000ns and 1 micros ? (I would undersatnd between binary and decimal multiples of bytes...but decimal fractions of seconds don't work this way)
1024 ns = 1 micro second ;)
Re: How “latency numbers everybody should know” decreased from 1990–2020
#177Okay since we're not going to improve the speed of light any time soon, here's my idea for speeding up CA to NL roundtrip: let's straight shot a cable through the center of the earth.
Read somewhere that neutrino particles are interesting in this regard, as they travel straight trough the earth.
They would go through the earth at the speed of light but detecting, let alone manipulating neutrinos is a very non-trivial task.
Re: How “latency numbers everybody should know” decreased from 1990–2020
#178Earlier quoted context omitted.
I don’t know, I have observed in my workloads, booting, game load, and building programs, that super fast ssds make almost no difference compared to cheap slow ssds. But any ssd is miraculous compared to a spinny drive Presumably video editing or something might get more of a win but I don’t know.
I'm talking about back in the day when I worked at Amazon with thousands of servers and in the 2001-2006 era we had basically no SSDs and it was all spinny rust (set the slider to 2006 and that is about my mental model). Spinny rust was always shit, so it was all about RAM and network and then the long tail siting on disk. I'm wondering how datacenter SSDs impact architectural decisions with e.g. 'microservices' by h…
Oh, SSDs have definitely had a big impact. On a cost per iop basis, they've been faster for a while, so any workload that's iop limited is on SSDs these days (assuming it doesn't fit in ram).
Re your prior comment about Redis style caches, it's worth noting Memcached now supports an SSD optimized external store. It identifies values where it'd be beneficial to spill them to SSD and does so, holding metadata in ram such that the object can be served in a single io (size permitting), and that there's no io required at all to delete/expire an item. It can saturate just about any SSD array you can build right now assuming your network can keep up.
It'll take a while, but if you skim the last decade or so of VLDB papers, you can see lots of compelling research into databases that are SSD optimized. It'll take some time for this to coalesce into proven industry solutions but it'll definitely happen.
And even with existing databases, I think a lot of people still underestimate what can be done with a sql database on a machine with a beefy SSD array. With more modest scale systems lots of people cargo culting an architecture built around say a cassandra cluster when something much more straightforward would easily suffice.
In any case, having millions of ios/sec be totally affordable in a server is a huge shift, and I feel like we still have a lot of layers and inertia in the way of fully utilizing that.
Re: How “latency numbers everybody should know” decreased from 1990–2020
#179SSD read speed for 1MB today is the same as RAM read speed for 1MB in 2008. I wonder what kind of implications this has for designing databases... or swap files.
We have memory mapped files now which look to the program like ordinary RAM but are backed by disk storage. (You still need to call sync to actually write back to disk.)
Re: How “latency numbers everybody should know” decreased from 1990–2020
#180Earlier quoted context omitted.
It also tells us that the speed of light has not increased. (well, speed of signal on a PCB track is roughly 2/3 light and determined by the transmission line geometry and the dielectric constant, but you all knew that)
And Speed of light within Glass. We could still get that 1/3 back when we could somehow make ultra long distance hollow cable. We could get that Packet round trip from 150ms to 100ms. But I dont think hollow cable are anywhere close to commercial launch.
Starlink will get us there for at least long-distance connections once they have the laser inter-sat links fully connected.