ack(3,8) was reported as "segfault" for the C impl in the previous
whitepaper revision. That was a stale observation — C has --fast
(bytecode VM with explicit frame stack) that handles deep recursion
cleanly. The benchmark table compared the wrong modes.
Corrected apples-to-apples:
- Python --fast (bytecode VM) — 17,004 ms on ack(3,8)
- C --fast (bytecode VM) — 1,433 ms **fastest of the three**
- asm native (tree-walker) — 2,322 ms
C's --fast wins every workload. asm still beats Python --fast by
~7x despite being a tree-walker, because it skips Python's per-op
overhead entirely.
c/main.c: --help text updated to clarify that --fast is required
(or `ulimit -s unlimited`) for deep recursion in the default
tree-walker mode. Attempted flipping --fast to default; reverted
because that surfaced a cumulative-state buffer overflow in the
bytecode compiler that only triggers after the full 189-test
functional suite but not on isolated scripts. Left as a TODO in
the code comment. 189 C tests + full test-all still pass.
Whitepaper §6.4 table now shows all three impls in their
high-performance configuration. Also noted that a pthread-with-
larger-stack wrapper would let the C tree-walker handle deep
recursion without --fast — tracked as low-priority future work
since --fast is strictly faster regardless.
russell@unturf.com
027017f01d