https://abhishekmurthy.com/tags/performance/Recent content in performance on Abhishek MurthyHugo -- gohugo.ioen-usMon, 24 Nov 2025 16:05:24 -0500https://abhishekmurthy.com/posts/search-engine-fits-in-l3-cache/Mon, 24 Nov 2025 16:05:24 -0500https://abhishekmurthy.com/posts/search-engine-fits-in-l3-cache/The first version of my search engine was slower after I added an index. That sounds backwards, but it is a real failure mode. A bad index can turn a simple sequential scan into a pile of cache misses, hash lookups, tiny heap allocations, branchy score calculations, and random memory walks. The CPU stops doing search and starts waiting for memory. The target I wanted was intentionally unreasonable: a local search engine for a few hundred thousand short technical records that could answer ranked queries inside an interactive UI budget, while keeping the hot path small enough to stay friendly to an L3 cache.