TLBentries

TLB entries, or Translation Lookaside Buffer entries, are fundamental components of modern computer memory management. The Translation Lookaside Buffer, or TLB, is a specialized cache that stores the results of recent virtual-to-physical address translations. When a CPU needs to access a memory location, it first checks the TLB. If the corresponding translation is found in the TLB, known as a TLB hit, the physical address is retrieved very quickly, bypassing the slower page table lookup in main memory. This significantly speeds up memory access.

Each TLB entry typically contains a virtual page number and its corresponding physical frame number. It may also include additional control bits such as valid, dirty, and protection bits. The size of a TLB is usually quite small, ranging from tens to a few hundred entries, as it is implemented in fast hardware. When a translation is not found in the TLB, a TLB miss occurs. In this case, the CPU must consult the page tables in main memory to find the physical address. Once found, this translation is then typically added to the TLB, potentially evicting an older entry if the TLB is full.

The effectiveness of the TLB relies on the principle of locality, meaning that recently accessed memory pages are likely to be accessed again soon. A well-designed TLB with a high hit rate dramatically improves overall system performance by reducing the overhead associated with address translation. TLB misses, while infrequent in typical workloads, can incur a performance penalty as they require slower memory accesses.