It was a good article, thanks for writing it. But when you know you're addressing an ultra technical crowd, please leave out stuff like that, it distracts from very interesting content.

It was a simile to express the critical importance of latency of calculation and dispatch in the system; in a graspable form for the reader - when I don't really know their technical ability - as its a blog post about a game; rather than a technical paper in a journal. I did say "is like" ;-)

For example in the interest management; it is working out what custom messages to send to what players about each other and with 50k players in the same combat it needs to do this without it ballooning to 2.5Bn messages for a round of position updates - of which there are many per second per player; then convert these individual compressed output streams that are unique per player; and move on to the next set - and even then as stated in the article we are still at 267M messages a second.

its probably fair.

gamers "flip their shit" when ping is not steady, and are only happy at ~50ms response times. a 200ms response in video games is usually considered "unplayable".

In the meantime, a ping of 50ms is an eternity for most financial applications. For normal algorithmic/quant trading you usually want to stay under 10ms roundtrip. For HFT, anything above 100µs is pretty slow. Gives you some perspective.

It was more a reference to the required latency from message received on wire, to messages processed, routed and dispatched on wire - for the scale, rather than physical location and speed of light issues.

In any split-second game (and this article literally advertises "real-time twitch combat"), 200 ms is unplayable. With two players of equal skill, it comes down to "who can react quicker", and the 30 ping player will win every time.

Totally depends on the type of game and how the design is structured to deal with latency.

See my reference to SubSpace farther down, it's a highly skilled game that can be easily played on a ~250ms latency. The large majority of the game is predicting where the other player will be in ~0.75s and setting things in motion ahead of time to intercept them.

Any game based on prediction and designed for smooth re-integration of the game state can be done on latent connections. Heck there's even been some really impressive stuff in the fighting game space involving re-winding gamestate to resolve hits ~0.25s in the past(the original Counter-Strike does this as well, although not as well which is why you'd sometimes see people rubber-band back around a corner when hit).

Yep. Loved it when we moved from ISDN to an E1, Quake became a lot more intense for my opponents :)

50ms == milliseconds. In HFT, 50 milliseconds might as well be 5 years. Now 50 microseconds is quite fast, and 50 nanoseconds is where you want to be.

Very few HFT firms are routinely operating in the nanosecond range. Under 50 microseconds is where most lie, and under 10 microseconds is where you'll find the fastest algos. Fact is, at that point even if you're colo-ing as a market maker the length of cable makes a difference. FPGA's and even ASIC's are pretty much necessary since even a CPU with off-die memory is going to be too slow

HFT is increasingly harder to make profits in: the real growth is in algos operating in the low milliseconds range capturing real market activity and non simple arbitrage.

I'll counter that with: very few so called HFT forms are actually HFT. I've worked for two this way. My previous employer was Virtu financial (look them up, they IPO'd)