The Top of the Hour: Caches from the CPU to the CDN

Deep End Era. Engineering with Sankalp · Oct 28, 2026 · 58m

Every hour, on the hour, a travel company's pricing service slows to a crawl, and a tiny counter change has quietly eaten thirty percent of its servers. Backend lead Jarrah Okonkwo-Bell calls performance engineer Marit Esposito, whose first rule is that every performance problem is a question about where the data is. In episode one hundred and sixty three we climb the memory hierarchy from L1 to DRAM, see how sixty four byte cache lines and the MESI protocol turn independent counters into false sharing, meet cache-oblivious algorithms, Belady's impossible optimum and the policies that…