CS:APP 3e · Chapter 1.5 · Memory Hierarchy & Caching

CSAPP 01.5 - Memory Hierarchy & Cache Memories - Locality Simulator

Visualizing Figure 1.9 memory hierarchy: storage devices form a hierarchy where each level caches the level below.

FIGURE 1.9: AN EXAMPLE OF A MEMORY HIERARCHY CURRENT LEVEL: NONE (SYSTEM IDLE)
L6: Remote secondary storage (distributed file systems, Web servers) [empty] L5: Local secondary storage (local disks) (local disks / NVMe SSD / SATA HDD) [empty] L4: Main memory (DRAM) Holds disk blocks retrieved from local disks [empty] L3: L3 cache (SRAM) Holds cache lines retrieved from memory [empty] L2: L2 cache (SRAM) Holds cache lines retrieved from L3 [empty] L1: L1 cache (SRAM) Holds cache lines from L2 [empty] L0: Regs [empty] CPU registers hold words retrieved from cache memory. L1 cache holds cache lines retrieved from L2 cache. L2 cache holds cache lines retrieved from L3 cache. L3 cache holds cache lines retrieved from memory. Main memory holds disk blocks retrieved from local disks. Local disks hold files retrieved from remote disks. Smaller, faster, and costlier (per byte) storage devices Larger, slower, and cheaper (per byte) storage devices