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L1 cache

L1 cache definition

L1 cache refers to a type of high-speed static RAM (SRAM) that a processor uses to store information it will likely need to access immediately. Also known as the Level 1 cache, it is the smallest and fastest cache layer, often located directly on the CPU.

Because of its proximity to the CPU cores, data retrieval is rapid, ensuring that the CPU doesn't have to wait too long for the data it needs.

See also: disk cache

Where is the L1 cache used?

  • Storing frequently used data. By keeping a copy of frequently used data close to the CPU, the L1 cache reduces the time the CPU spends waiting for data from the main memory, ensuring smoother and faster operations.
  • Storing frequently used instructions. The CPU frequently reuses certain instructions such as arithmetic and logic operations, data transfer instructions, and system calls. . Storing these in the L1 cache helps the CPU access them quickly.
  • Split nature for efficiency: Often, L1 cache is split into two parts: L1d (for data) and L1i (for instructions). This separation allows the CPU to fetch instructions and data simultaneously, further optimizing the execution process.
  • Reducing memory traffic. By providing the CPU with most of its frequently used data and instructions, the L1 cache reduces the amount of traffic between the CPU and main memory. This not only speeds up CPU processes but also reduces the workload on the memory subsystem.