How does Julia's method cache work and why is it critical for performance?

Julia uses a method cache to store previously resolved method dispatches for fast lookup on repeated calls.

When a function is called, Julia performs multiple dispatch resolution based on argument types. This lookup can be expensive if repeated frequently. To avoid recomputation, Julia caches the mapping from type signatures to compiled method instances. Subsequent calls with the same types bypass method resolution and jump directly to compiled code. This is essential for high-throughput numerical workloads.