CPU scaling benchmark
workers
2 +1 main
iters total
500M
166666666/stream
elapsed
1474.78 ms
total CPU used
4343.56 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 | 3.39 | 3.4 | 1442.51 | 1439.11 | 0 |
| 1 | 1.886 | 1.9 | 15.42 | 1464.02 | 1448.6 | 21.69 |
| 2 | 1.446 | 3.37 | 16.31 | 1472.16 | 1455.85 | 29.78 |
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.