CPU scaling benchmark

W=0 W=1 W=2 W=3 W=4 W=6 W=8 W=9 W=10 W=12 W=16 iters: 100M 500M 1B 2B
workers
4 +1 main
iters total
500M
100000000/stream
elapsed
1228 ms
total CPU used
5228.64 ms
speedup
4.26×
vs serial
efficiency
85.2%
of 5× ideal
stream spawn ms spawned@ work start@ work end@ work ms reap wait ms
0 (main) 0 6.29 6.3 1171.02 1164.72 0
1 1.878 1.89 17.14 890.48 873.34 0.13
2 1.51 3.43 17.91 974.84 956.93 0.19
3 1.334 4.78 19.95 1063.57 1043.62 0.21
4 1.475 6.28 35.21 1225.24 1190.03 54.35
main
w1
w2
w3
w4
    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.