SPEC CPU Benchmark (Cont.)
To simplify the marketing of computers, SPEC decided to report a single number to summarize all 10 integer benchmarks.
Dividing the execution time of a reference processor by the execution time of the measured computer normalizes the execution time measurements; this normalization yields a measure, called the SPECratio, which has the advantage that bigger numeric results indicate faster performance.
A summary measurement is obtained by taking the geometric mean of the SPECratios.
( Π SPECratioi )1/n,
where Π ai means the product a1×a2×...×an, i = 1 .. n
The following table shows results for SPEC2017 benchmark programs running on an AMD Barcelona:
| Name |
Instruction count × 109 |
Execution time (seconds) |
Reference time (seconds) |
| perl |
1750 |
400 |
8660 |
| mcf |
432 |
1000 |
8500 |
Find the CPI if the clock cycle time is 0.25 ns:
CPIperl = CPU time / ( Instruction count × Cycle time )
= 400 / ( 1750 × 109 × 0.25 × 10-9 ) = 0.91 cycles / instr.
CPImcf = 1000 / ( 432 × 109 × 0.25 × 10-9 ) = 9.26
Find the SPEC ratio:
SPECratioperl = Reference time / Execution time
= 8660 / 400 = 21.65
SPECratiomcf = 8500 / 1000 = 8.5
For these two benchmarks, find the geometric mean:
( 21.65 × 8.5 )½ = 13.57