What are some real-world examples of cache coherency?

What are some real-world examples of cache coherency?

Cache coherency refers to the consistency of data stored in local caches of a shared resource. A common example is multi-core processors where each core has its own cache. If one core updates a value, cache coherency protocols ensure that other cores see the updated value.

Can you explain how cache coherency works in multi-core processors?

Sure! In multi-core processors, each core has its own cache. When one core modifies data, cache coherency protocols like MESI (Modified, Exclusive, Shared, Invalid) ensure that other cores either update their caches or invalidate the stale data, maintaining consistency.

What happens if cache coherency is not maintained?

If cache coherency is not maintained, different cores may work with outdated or inconsistent data, leading to errors, crashes, or unpredictable behavior in applications that rely on shared data.

Are there any specific protocols used for cache coherency?

Yes, there are several protocols, including MESI, MOESI, and MSI. Each has its own method for managing cache states and ensuring data consistency across multiple caches.