Memory access pattern

In computing, a memory access pattern is the pattern over time with which a system accesses memory.

A memory access patterns differ in the level of locality of reference and drastically affect cache performance.

At one extreme is the sequential memory access pattern , where data is read , processed, and written in a straightforward incremental manner. Strided or simple 2D access patterns are similarly easy to predict, and are found in implementations of linear algebra and image processing. Loop tiling is an effective approach.

In 3D rendering, access patterns for texture mapping and rasterization of small primitives (with arbitrary distortions of complex surfaces) are often far from linear, but still exhibit spatial locality . This can be turned into good memory locality via some combination of morton order and tiling for texture maps and frame buffer data, or by sorting primitives via tile based deferred rendering.

Data structures which rely heavily on pointer chasing can often produce poor locality of reference, although sorting can sometimes help.

At the opposite extreme is a truly random memory access pattern.