Cycles per Retired InstructionCycles per Retired InstructionClockticks / Instructions Retired
This ratio is also called Cycles per Instructions (CPI).
When you want to determine where to focus your performance tuning effort, the CPI is the first ratio to check. A good CPI rate indicates that the code is executing optimally.
As a general guide these numbers have been derived from experienced performance engineers:
Good |
Poor |
|---|---|
|
0.75 |
4 |
A poor CPI ratio indicates one of the following:
The selected code could probably be optimized to execute more efficiently on the processor.
The selected code includes string instructions or micro-code.