Latency (execution time):
time to finish a fixed task
Throughput (bandwidth):
number of tasks per unit time
Calculate speed up
Average performance
CPU Performance
CPI: Cycles/instruction
IPC = 1/CPI
- Used more frequently than CPI
- Favored because “bigger is better”, but harder to compute with
What is the CPI? (1 cycle+2 cycles +3 cycles) / 3 instrs= 2
Calculated in another way: 33% x 1 + 33% x 2 + 33% x 3 = 2
Some examples:
MIPS
Million instructions per second <- IPC
