Cycles Per Instruction

computer-architecture

Definition

Cycles Per Instruction

Cycles per instruction is the average number of clock cycles required to execute one instruction.

It is the reciprocal of instructions per cycle:

$$\mathrm{CPI}=\frac{1}{\mathrm{IPC}}$$

Effects of Static Branch Mispredictions

$$\mathrm{CPI}=1+b\cdot p\cdot m$$

where

• $b$ is the branch rate
• $p$ is the branch cycle misprediction penalty
• $m$ is the branch misprediction rate