TLBFlushes

The Translation Lookaside Buffer (TLB) is a hardware cache that stores recent virtual-to-physical memory address translations. TLB flushes are operations that clear or invalidate entries in this cache, which becomes necessary when memory mappings change. These operations occur during context switches, when page tables are modified, or when virtual memory systems are reconfigured.

TLB flushes can be selective, targeting specific entries, or global, clearing the entire buffer. The frequency and granularity of TLB flushes significantly impact system performance, as excessive flushing forces the processor to rebuild the cache with new translations, increasing memory access latency.

Modern processors implement various TLB management techniques to minimize performance impacts, including hierarchical TLBs with different sizes for various page sizes, and TLB shootdown mechanisms in multi-core systems to maintain consistency across processor caches. The efficiency of TLB flushing algorithms is particularly important in workloads with frequent address space changes or large memory footprints, where excessive flushing can become a significant performance bottleneck.