Assume you have the following relative instruction frequency

Assume you have the following relative instruction frequency and their respective cycles per instruction:

Arithmetic/logical instructions 57% with 1 cycle
Load instructions 22% with 3 cycles
Store instructions 6% with 2 cycles
Unconditional branches 10% with 2 cycles
Conditional branches 5% wit 2 cycles

What is the average cycles per instruction?

Solution

If we say that there are 100 instructions, then:

57 of them are Arithmetic/logical

22 of them are Load instructions

6 of them are Store instructions

10 of them are Unconditional branches

5 of them are Conditional branches

(57 * 1) + (22 * 3) + (6 * 2) + (10 * 2) + (5 * 2) = 165 cycles/100 instructions

Therefore, there are 1.65 Cycles per instruction.