CPU scaling benchmark
workers
2 +1 main
iters total
500M
166666666/stream
elapsed
1471.71 ms
total CPU used
4343.16 ms
speedup
2.95×
vs serial
efficiency
98.3%
of 3× ideal
| stream | spawn ms | spawned@ | work start@ | work end@ | work ms | reap wait ms |
|---|---|---|---|---|---|---|
| 0 (main) | 0 | 3.83 | 3.84 | 1447.53 | 1443.69 | 0 |
| 1 | 2.108 | 2.13 | 16.83 | 1464.87 | 1448.04 | 17.47 |
| 2 | 1.663 | 3.82 | 17.72 | 1469.15 | 1451.43 | 21.72 |
main
w1
w2
fork+handshake
CPU work
parent reap wait
what this measures
Each stream runs a tight integer LCG loop — working set is one CPU register, no memory access,
no shared data. Speedup = sum(stream CPU time) / wall-clock elapsed. Efficiency = speedup / (workers+1).
100% efficiency means perfect linear scaling; less than 100% is the cost of serial fork setup,
reap tail, SMT/core contention.