Instruction prefetch

In computer architecture, instruction prefetch is a technique used in central processor units to speed up the execution of a program by reducing wait states.

Prefetching occurs when a processor requests an instruction or data block from main memory before it is actually needed. Once the block comes back from memory, it is placed in a cache. When the instruction/data block is actually needed, it can be accessed much more quickly from the cache than if it had to make a request from memory. Thus, prefetching hides memory access latency and hence, it is a useful technique for addressing the memory wall issue.