Cache Coherency and Performance
Understand CPU cache mechanisms, cache lines, and how to write assembly code that leverages cache locality for maximum performance.
What Are CPU Caches?
Modern CPUs are incredibly fast, but main memory (RAM) is much slower. This speed difference creates a bottleneck.
CPU caches are small, super-fast memory areas located directly on the CPU chip. They act as temporary storage for frequently accessed data and instructions, bridging the speed gap between the CPU and RAM.
Understanding Cache Hierarchy
Caches are organized into a hierarchy, usually with three main levels:
- L1 Cache: Smallest (tens of KBs), fastest, located directly on each CPU core. Stores data and instructions the core needs right now.
- L2 Cache: Larger (hundreds of KBs), slower than L1, often per-core. Acts as a secondary buffer.
- L3 Cache: Largest (several MBs), slowest, but faster than RAM. Shared across all CPU cores on the chip.
All lessons in this course
- Cache Coherency and Performance
- Hand-Optimizing Critical Sections
- Buffer Overflows and Shellcode
- Branch Prediction and Speculative Execution