GoKawiilEngineer shows how to make a spin-lock 5.7x faster and 5.4x more energy-efficient
A developer walks through optimizing a basic spin-lock implementation in C++, starting from a naive atomic exchange loop that slows dramatically under contention. Benchmarks show the naive version taking 3.14 ns uncontended but ballooning to 246 ns with four threads, driven by cache-line contention and branch mispredictions. Through iterative refinements, the author achieves a version that is 5.7 times faster and consumes 5.4 times less energy than the original.