15. Conclusion: Which Should You Choose?
"Should I always use threads?"
No. It depends on your priorities:
- Stability and isolation (one component failing shouldn't crash the system) → Multi-process (Chrome, Nginx).
- Performance and resource efficiency (fast data sharing, low overhead) → Multi-threading (Tomcat, game servers).
- Massive concurrency (thousands of simultaneous I/O operations) → Green threads/Event loops (Go, Node.js).
- Thread safety by design (zero-cost abstractions, compile-time guarantees) → Rust ownership model.
This is a pattern worth internalizing early: threading feels "faster" because it's lighter-weight, but one unhandled exception can bring down the entire application. When stability matters, processes with a supervisor pattern are the safer choice.
The right starting question is: "What happens when this fails?" That question determines whether to reach for processes, threads, or async. As engineers, we don't just write code—we manage trade-offs.