Cache Miss: What It Means and How It Affects Your System Performance
Cache miss happens when your processor searches for data in the cache memory but doesn’t find it there. When you or I run a program or open a file, the processor first checks the cache to access the required data quickly. But if that data isn’t available in the cache, a cache miss occurs, and the processor has to fetch it from the main memory, which is slower.
When we experience frequent cache misses, it can slow down the system noticeably. This often points to issues with how memory is being managed or suggests that the system could benefit from additional RAM. If you’ve ever noticed lag during multitasking or slow program launches, high cache miss rates might be part of the reason.
Types of Cache Misses
Compulsory Miss (Cold Start Misses or First Reference Misses): This type of miss occurs when a block is accessed for the first time. In such cases, the block needs to be brought into the cache as it is not present initially.
Capacity Miss: This type of miss happens when the working set of a program exceeds the storage capacity of the cache. As a result, some blocks need to be evicted from the cache during program execution since it cannot accommodate all the required blocks.
Conflict Miss (Collision Misses or Interference Misses): Conflict misses mainly occur in set-associative or direct-mapped block placement strategies. When multiple blocks are mapped to the same set or block frame, this type of miss occurs due to the limited number of available slots in that set.
Coherence Miss (Invalidation): Coherence misses occur when other external processors, such as I/O devices, update the memory. These misses happen due to the need for cache coherence, ensuring that all caches have the most up-to-date data.
Applications of Cache Misses
Cache Misses in WordPress Websites: On WordPress sites, a cache miss means the page isn’t stored in the cache and must be regenerated from the database, slowing load time. Using caching plugins can help reduce cache misses and speed up the site for better user experience.
Cache Misses in Computer Processors: In processors, a cache miss happens when the needed data isn’t in the cache and must be fetched from slower main memory. This can slow down program execution. Reducing cache misses through techniques like larger caches, better organization, and prefetching boosts performance.
Cache Misses in Website Development: In website development, cache misses occur when the browser cannot find stored elements like images, CSS, or JavaScript in its cache, forcing a fresh request from the server. This increases page load time. Managing cache effectively with strategies like setting proper cache lifetimes and validation can improve performance.
