The Monolith vs. Microservice Tax

In a monolith, calling Method B from Method A is a function call on the stack. In a microservice, that same call involves:

1. Serialization (JSON/Binary).
2. The TCP Handshake (or connection reuse).
3. Network propagation.
4. Deserialization at the target.

The 'Sidecar' Tax

Modern platforms like Istio or Linkerd use Sidecar Proxies (Envoy) to handle security and observability. While powerful, every request now hops through two extra proxies (the source sidecar and destination sidecar).

In high-concurrency systems, this adds 1-3ms of latency per hop. In a deep microservice call chain (e.g., 5 services deep), the sidecar latency can exceed the actual business logic time.

Conclusion

Distributed systems are systems of tradeoffs. To build a high-performance cloud application, you must account for the microseconds lost in translation and the milliseconds lost in flight.