Explain the purpose and function of CPU caches. What are the different levels of cache memory, and how do they impact CPU performance?

CPU caches serve as high-speed storage units that store frequently accessed data and instructions to reduce the latency of memory access and improve overall CPU performance. Caches are designed to exploit the principle of locality, which states that programs tend to access a relatively small subset of data and instructions repeatedly within a short period of time. By storing this frequently accessed data and instructions in caches, CPUs can minimize the time spent waiting for data to be fetched from slower main memory.