[altmind]

Many trading companies now utilize over-the-horizon radio. Its the fastest, most direct connection available. But even without this:

- cpu thermal profiles and power governors

- cpu affinity

- non-evented io(if you prefer latency over the number of clients served)

- network interrupt coalescing(actually, disabling coalescing), network msi-x, hardware offloads, 10gb fiber or DAC connections(very cheap nowadays)

- lock-free and kinda-crdt data structures(between threads)

- predictable memory allocations(better - no allocations on critical path)

- specialized logging and tracing(no stdio)

can drive you quite far.

[bloomer]

What is over the horizon radio? I am familiar with over the horizon radar, but not radio for communications. Do you have any references?

[walrus01]

Shortwave radio with big-ass yagis and dipoles, aimed at each other in point-to-point links. Very low data rates, carrying custom messaging protocols, but also measurably less latency on critical paths such as NY-Chicago or London-Tokyo.

There is a big crossover in tech with shortwave band military over the horizon communications systems, and also serious ham radio enthusiasts who use big yagis and antenna rotators to talk to each other from opposite sides of the planet.

Things like chained 6 and 11 GHz microwave between NY-Chicago, which was the "hot new thing" in HFT 7-8 years ago to achieve better than fiber latency on that route, seem quaint now.

[altmind]

Sorry, used wrong word. "Skywave" is a better term.