Scalable Counter Design

What this scalable counter design question tests

This is an easy operating systems question that probes your understanding of lock contention and how to mitigate it in concurrent systems. It's the kind of foundational question used to confirm that candidates grasp the tension between correctness (mutual exclusion) and performance (minimizing serialization).

To approach questions like this, think about what happens when many threads try to increment a shared counter simultaneously. A naive implementation—one global lock protecting a single counter—becomes a bottleneck as contention rises. The question asks you to recognize architectural patterns that reduce this pressure without sacrificing safety.

• Lock granularity and its trade-offs
• Partitioning and local updates
• Cache coherence and false sharing
• Synchronization primitives and their costs