Every Byte Matters
8 hours ago
- #hardware awareness
- #performance
- #memory optimization
- Programmers often overlook the impact of field size on performance, focusing instead on algorithmic complexity.
- Cache line size is 64 bytes; reading a single byte loads the entire line, making spatial locality important.
- Array of Structs (AoS) can waste cache space, while Struct of Arrays (SoA) packs data more efficiently, yielding up to 30x speed improvements.
- Sequential access benefits from CPU prefetching, but random access patterns in structures like hash maps rely on the entire working set fitting in cache.
- Larger struct sizes push data into slower cache levels, significantly increasing latency, especially as the working set grows.