Tiered Compilation

Tiered Compilation is a JIT compilation strategy that employs multiple compilers of increasing sophistication, escalating code from simpler to more complex optimizers as runtime profiling proves its importance. A typical pipeline begins with an interpreter, progresses to a fast baseline compiler, and culminates in an aggressive optimizing compiler — each tier trading compilation speed for execution speed. This architecture recognizes that not all code deserves the same optimization effort: cold paths should compile quickly, while hot paths should compile carefully. The HotSpot JVM's C1/C2 compiler pair is the canonical implementation, though V8's Ignition/TurboFan and .NET's Tiered JIT follow the same pattern. Tiered compilation is an instance of resource allocation in computational systems: optimization budget is spent where it yields the most return.