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3 Commits
Author SHA1 Message Date
Robert Allan JamesandClaude Sonnet 5 e51a8d229e Fix stadium_grant_quota() donor floor; rerun std79 DoE clean, 81/81 (FABRIC-3.md §XVII)
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capsule_birth.c hardcoded every new VM's initial Stadium quota grant to split
from Hera specifically. Since a grant always halves whatever the donor
currently has, Hera's own free list converges toward empty after a bounded
number of grants — independent of whether the Stadium as a whole still had
spare capacity, since VMs she'd granted to earlier typically still held
nearly all of their own share untouched. Past that point every subsequent
VM birth's Stadium grant would be silently refused (soft-failed, non-fatal
by existing design), even with plenty of capacity sitting idle elsewhere.

Fixed by adding an O(1)-maintained free_count to StadiumVMQuota (incremented
in stadium_evict(), decremented at both of stadium_admit()'s free-list-pop
sites, set/adjusted in stadium_grant_quota()'s own split — this also let
grant_quota drop its old O(free-list length) counting walk in favor of an
O(1) read) and stadium_best_donor(), an O(live VM count) scan over quota
slots returning whichever in-use VM currently has the most free cells.
capsule_birth.c's birth path now splits from that VM instead of
unconditionally vm_uuid_hera().

Verified with another full rerun of the 3x9x3 std79 DoE campaign from
scratch — same discipline as the prior Stadium fix (any defect repair
reruns the whole DoE from the top) — one continuous boot per architecture,
all 9 identities simultaneously live throughout. 81/81 trials correct, 0
mismatches, DOE-RUN header sequence md5-identical to every prior run.
aarch64 ~280s total (vs ~290s for the O(ncells)-scan fix alone — confirms
no regression). Both known Stadium defects are now closed together on one
clean campaign rerun.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EXieurDfDSsDFdnSyusuWo
2026-09-11 17:20:07 -04:00
Robert Allan JamesandClaude Sonnet 5 9eff122090 Fix aarch64 Stadium/COOL O(ncells) scan; rerun std79 DoE clean, 81/81 (FABRIC-3.md §XVI)
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Root cause of the 90+ minute aarch64 VM-birth stall found in §XV: stadium_admit()'s
eviction-fallback scan iterated the entire stadium_ncells array filtered by owner,
not the calling VM's own resident cells as its own doc comment claimed. Combined
with stadium_grant_quota() always splitting from Hera's shrinking free list and
stadium_word_dispatch() calling stadium_admit() per distinct word a VM's capsule
executes, this compounded into a real O(n) blowup — catastrophic specifically on
aarch64 because its -m 4096 (vs 1024 on amd64/riscv64) inflates the kmalloc heap
kmalloc_init() bisects down to, which inflates stadium_ncells 4x (335,544 vs 83,886
cells, measured from boot logs).

Fixed by threading a real per-VM doubly-linked resident-cell list
(StadiumVMQuota.resident_head + stadium_resident_next[]/stadium_resident_prev[])
so the fallback scan is bounded by that VM's own resident count, not the global
cell array size.

Verified with a full rerun of the 3x9x3 std79 DoE campaign from scratch: one
continuous boot per architecture, all 9 identities simultaneously live throughout
(the 3-boot aarch64/riscv64 batching workaround is no longer needed). 81/81 trials
correct, 0 mismatches, DOE-RUN header sequence md5-identical across all three raw
logs. Identity 04's attach on aarch64, which stalled 90+ minutes before, now
completes in ~34s; full boot-to-DoE-complete in ~290s.

Corrects an earlier misreading (carried into §XV, std79-doe.fth's comments, and
the project memory note) that described the symptom as a runaway "335,000+ cycles"
dispatch counter — those were cell array indices, not an event count.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EXieurDfDSsDFdnSyusuWo
2026-09-11 16:37:44 -04:00
Robert Allan JamesandClaude Sonnet 5 e2abc56306 3(arch) x 9(identity) x 3(rep) randomized full-factorial std79 DoE: 81/81 correct (FABRIC-3.md §XV)
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Formal successor to §XII's ad hoc exerciser campaign, requested as a
genuine randomized full-factorial design matching this project's own
DoE methodology (capsules/doe.4th's Fisher-Yates shuffle), and written
entirely in FORTH per explicit request -- not host-orchestrated shell
scripting.

experiments/std79-doe/std79-doe.fth: builds a 27-cell (9 identity x 3
replicate) run matrix, Fisher-Yates shuffles it with a fixed seed
(matching doe.4th's own default), then dispatches each of the 24
exerciser test cases directly into the target identity's own live VM
via VM-EXEC -- no console USE redirection, no per-trial host
interaction. The zuse case runs as directly-compiled native code
(RUN-TEST-NATIVE) rather than VM-EXEC targeting "Hera" herself:
VM-EXEC's own vm_state_push/pop only saves rsp/exit_colon/ecw_nesting,
not input_buffer/input_pos, so a self-targeting call while this
capsule's own vm_interpret call is still mid-line would risk exactly
the class of bug the idle-tick reentrancy guards exist for.

amd64: all 27 trials ran with all 9 identities simultaneously live in
one boot -- clean, zero mismatches.

aarch64: hit a real, uninvestigated bug attaching all 9 simultaneously
-- the 6th live VM's birth stalled for 90+ minutes at 100%+ CPU with a
Stadium COOL-dispatch counter already at 335,000+ cycles, versus tens
of thousands at the same checkpoint for earlier identities. Not
root-caused here (flagged in FABRIC-3.md for later); worked around by
splitting into 3 boots of 3 simultaneously-live identities each, every
boot sharing the same seed so the master 27-slot shuffle is identical,
filtered per boot by a new ACTIVE-LO/ACTIVE-HI range
(EXEC-STD79-DOE's signature: seed lo hi -- ). run_id is always the
slot's true position in the master shuffle, so trial order stays
comparable across boots -- standard DoE blocking.

riscv64: same 3-boot pattern, clean.

Grand total: 81/81 trials correct, 0 mismatches, across all three
architectures, all nine identities, all three replicates.

Also flagged (FABRIC-3.md §XIV, not fixed): attaching several WIREBIND
identities near-simultaneously (whether via rapid hotplug or all
present from boot) causes the kernel to silently detect only some of
them -- confirmed at the host/QMP level that every device was genuinely
present. Worked around throughout this campaign by attaching one
identity at a time with confirmed waits; real hardware hotplug could
hit the same gap, so it's a genuine robustness concern, not just a
test-harness inconvenience.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EXieurDfDSsDFdnSyusuWo
2026-09-11 13:59:32 -04:00