Debugging False Sharing

This post is my own summary of Netflix’s tech blog post Seeing through hardware counters: a journey to threefold performance increase, written the way I understood it, with some background I added along the way. The original post is the authoritative source, so check it directly for exact figures and details. The Problem A Netflix service was running short on CPU, so the team scaled its nodes up 3x. Given the CPU-intensive workload, they expected throughput to scale roughly in step. Instead, they got about a 25% improvement, and tail latency actually got worse. ...

December 12, 2025 · 5 min · Donghyung Ko