What is Julia's garbage collection mechanism and how does it impact performance?

Julia uses a generational garbage collector that automatically frees unused memory, but allocation-heavy code can degrade performance.

Julia's GC is designed to optimize short-lived object cleanup. Objects are classified into generations based on lifespan. New objects are frequently scanned, while long-lived objects are scanned less often. However, excessive allocations in performance-critical loops can trigger frequent GC pauses, reducing throughput. Julia developers often optimize by minimizing heap allocations and preferring stack allocation through immutable structs.