# quadratic scaling sweep (sys-time microseconds, 4 conns each):
$ ./bench 1 4096 4 19000 | tail -2
cp_time delta: user=0 nice=0 sys=107765 intr=0 idle=432271
kernel-ticks (sys+intr) = 107765  (100/sec)
$ ./bench 1 8192 4 19000 | tail -2
cp_time delta: user=9046 nice=0 sys=315302 intr=0 idle=1466528
kernel-ticks (sys+intr) = 315302  (100/sec)
$ ./bench 1 16384 4 19000 | tail -2
cp_time delta: user=26932 nice=0 sys=1153292 intr=0 idle=5317853
kernel-ticks (sys+intr) = 1153292  (100/sec)

# sys-time per 2x request-size increase: 107765 -> 315302 -> 1153292
#   (2.9x, then 3.7x) => quadratic, approaching the 4x O(n^2) asymptote.
# ~0.29 CPU-seconds of netisr-thread system time burned by 16KB of attacker
# data in ONE connection (amplification ~18,000 CPU-us per attacker byte).