THE BUG. str_char_code() and str_slice() each called strlen() on every
invocation. The lexer walks source one character at a time, so every character
access rescanned the whole remaining input: O(n) per character over n
characters = O(n^2).
el_val_t str_char_code(el_val_t s, el_val_t i) {
...
int64_t n = (int64_t)strlen(str); // <- O(n), every call
if (idx < 0 || idx >= n) return 0;
return str[idx];
}
HOW IT WAS FOUND. Not by reading code — by sampling the running process, which
is the same method that resolved tonight's engram outage after four wrong
theories. A geometric sweep of synthetic sources showed wall-clock rising 3.0x,
3.0x, 4.0x, 4.14x per doubling (converging on 4x = quadratic), and a stack
sample put 779 of 779 samples inside lex(), every one bottoming out in
_platform_strlen via str_char_code and str_slice.
THE FIX. Remember the length instead of recomputing it. The subtlety is
INVALIDATION: El strings are arena-allocated, so a freed pointer can be reused
for a different string at the same address, and a naive pointer-keyed cache
would hand back a stale length and read past the end of the new string —
trading a performance bug for a memory-safety one. So entries carry a
generation, a hit requires pointer AND generation to match, and every path that
frees or mutates a runtime string bumps the generation: el_arena_pop,
seed_request_end, __str_set_char. Stale entries cannot be believed; they miss
and recompute.
MEASURED, same host, same inputs:
n(fns) before after
512 0.10s 0.01s
1024 0.37s 0.02s
2048 1.51s 0.03s 50x
the compiler's own 422 KB source concatenated (DESIGN.md's 3.58s case):
3.55s -> 0.03s 118x
The speedup GROWS with input size, which is the signature of removing a
complexity class rather than a constant factor. After the fix each doubling
adds ~0.01s: linear.
CORRECTNESS, verified rather than assumed:
- byte-identical output on every sweep input (n = 128..2048)
- byte-identical output on the 422 KB compiler concatenation
- byte-identical output on tests/runtime/string_test.el
- self-hosting fixpoint byte-identical
- new tests/runtime/str_cache_test.el: 17 assertions covering bounds, empty
strings, negative indices, slice clamping, distinct strings not sharing a
cached length, 1000 interleaved strings forcing cache-slot collisions, and
a grown string not reporting its old length. All pass.
This is the defect that made dist/soul.c a committed artifact: elc could not run
in CI because it needed 24 GB+ and minutes. It needs neither now.
Cancellation-token control channel checked at every step boundary lets a
coordinator PAUSE/RESUME/REDIRECT/KILL a running worker mid-task instead of
waiting for the whole (possibly wrong) plan to finish. Bounded purviews
mean no half-committed state to unwind on interrupt. Includes a proof
harness (proof.el, run.sh) comparing a broken non-interruptible worker
against the new one under identical kill/redirect/pause timing.
Distinct from the already-preserved swarm-ccr orchestrator (fan-out/
converge dispatch): this is single-worker interruptibility, a
complementary mechanism, not a duplicate.
Establish lang/runtime/ as the ONE canonical el runtime (from the active
runtime that carries hebb/emb persistence + the new WAL); repoint the el CI
publish, engram build, elb default, and in-repo build scripts to it; delete
the el-compiler/runtime + lang/releases/ forks; add scripts/check-single-runtime.sh
drift guard.
Fixes a live prod bug: the el CI published el-runtime-c/-h from the LAGGING
el-compiler fork (0 hebb refs), so the shipped soul never persisted Hebbian
edge weights — learned co-activation was wiped on every restart. Publishing
from canonical ships the stranded 'learning that cannot outlive the process'
fix.
WAL storage engine + integrity fixes (DELETE->tombstone + store-layer
protection, safe data-dir default) ride in behind ENGRAM_WAL (default off =
byte-identical to today). Verified: engram elb per-module build clean, WAL
gate 66/66, native smoke ok, drift-guard green.
bigmerge
will.anderson