How High-Frequency Trading Systems Remove Every Microsecond of Latency

I recently went down a rabbit hole connecting OS internals with real-world low-latency systems. While learning about process management in operating systems, I kept wondering: “Where does this level of optimization actually matter?” That eventually led me to High-Frequency Trading systems — one of the few domains where microseconds can literally mean money. So I decided to break down how modern HFT systems push OS, hardware, and networking to their limits. What is HFT (Really)? At a surface leve