Cache Coherence

What this cache coherence protocol question tests

This is an easy computer-architecture question that checks whether you understand the fundamental protocols used to keep caches consistent across multiple processors in a shared-memory system. It is foundational knowledge for anyone working on low-latency systems or performance-critical infrastructure.

Cache coherence becomes critical in multi-core and multi-processor environments, where different CPUs may hold copies of the same memory location in their private caches. A coherence protocol defines the rules and message-passing mechanisms that ensure all processors see a consistent view of memory. This question asks you to recognise which protocols are actual, named approaches to solving this problem.

• Write-invalidate vs. write-update strategies
• Snooping and directory-based protocols
• State transitions in coherence protocols
• Why coherence matters for correctness and performance