Tech Musings

Aug 20, 2026 · Fundamentals

Four JMH Cases Reveal How Java JIT Optimizes at the Assembly Level

The article walks through four carefully designed JMH benchmarks—method inlining, SIMD vectorization, lock elimination, and a Netty AsciiString regression—to show how JVM JIT optimizations appear in assembly, explain the performance impact (up to 1500×), and demonstrate how to diagnose and fix real‑world issues using assembly analysis.