On: It's always TCP_NODELAY

[Bluecobra]

I agree, it has been fairly well known to disable Nagle's Algorithm in HFT/low latency trading circles for quite some time now (like > 15 years). It's one of the first things I look for.

[Scubabear68 → Bluecobra]

I was setting TCP_NODELAY at Bear Stearns for custom networking code circa 1994 or so.

[kristjansson → Scubabear68]

This is why I love this place

[Reason077 → Bluecobra]

Surely serious HFT systems bypass TCP altogether now days. In that world, every millisecond of latency can potentially cost a lot of money.

These are the guys that use microwave links to connect to exchanges because fibre-optics have too much latency.

[jm__87 → Reason077]

They still need to send their orders to an exchange, which is often done with FIX protocol over TCP (some exchanges have binary protocols which are faster than FIX, but the ones I'm aware of still use TCP)

[mcoliver → Bluecobra]

Same in M&E / vfx