cc-metric-collector/collectors/likwid/groups/k10/CPI.txt
2021-03-25 14:47:10 +01:00

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SHORT Cycles per instruction
EVENTSET
PMC0 INSTRUCTIONS_RETIRED
PMC1 CPU_CLOCKS_UNHALTED
PMC2 UOPS_RETIRED
METRICS
Runtime (RDTSC) [s] time
Runtime unhalted [s] PMC1*inverseClock
CPI PMC1/PMC0
CPI (based on uops) PMC1/PMC2
IPC PMC0/PMC1
LONG
Formulas:
CPI = CPU_CLOCKS_UNHALTED/RETIRED_INSTRUCTIONS
CPI (based on uops) = CPU_CLOCKS_UNHALTED/RETIRED_UOPS
IPC = RETIRED_INSTRUCTIONS/CPU_CLOCKS_UNHALTED
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This group measures how efficient the processor works with
regard to instruction throughput. Also important as a standalone
metric is INSTRUCTIONS_RETIRED as it tells you how many instruction
you need to execute for a task. An optimization might show very
low CPI values but execute many more instruction for it.