Closes FABRIC-2.md's last open §12 Q5 question. fleet_heartbeat_tick_count
is fed by every live VM's own vm_tick(), not one VM's, so it was reaching
HEARTBEAT_INFERENCE_FREQUENCY (shared/borrowed from the per-VM inference
gate) several times faster than intended with more than one VM live -
backwards from FABRIC.md §22.4's required ~1000:1 separation.
What's actually gated turned out to be low-stakes: vm_physics_tick()
(capsule_vm_physics.c:397) is a passive statistics refit - re-sorts a
window of past heat-transfer samples and recomputes a median rate
estimate. It doesn't move heat or arbitrate capacity. Firing too often
just meant a noisier statistic recomputed more frequently than planned,
not incorrect behavior.
Considered and explicitly rejected: scaling the threshold by live VM
count at the check site. That's the first brick of a scheduler - reading
fleet state to adjust a rate dynamically - which this project has
deliberately avoided building. Implemented instead: STADIUM_CAPACITY_TICK
(existing Kconfig symbol, defined but never read by any code path) now
gates vm_physics_heartbeat_tick()'s call directly, replacing the borrowed
HEARTBEAT_INFERENCE_FREQUENCY. Default bumped 1000 -> 4000, a flat
constant picked once for Tripod's known 4-VM topology, same kind of
placeholder as every other frequency knob in Kconfig.kernel - not
computed from anything at runtime. Renamed fleet_last_inference_tick ->
fleet_last_capacity_tick to match. Still one clock, one counter
(fleet_heartbeat_tick_count) - just a bigger flat divisor on it.
Three-arch QEMU acceptance: all clean to ok>, identical Stadium
conservation invariant on all three (resident_sum=43691 reservoir=21845
sum=65536). logs/20260815-093425/amd64, logs/20260815-093521/aarch64,
logs/20260815-093641/riscv64.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Replaces STADIUM_MAX_VM_COUNT (Kconfig, hardcoded default 4) with a
boot-time computation, mirroring the pattern stadium_boot_init() already
used for the cell pool. New Kconfig STADIUM_VM_MEMORY_PERCENT (default
50): max_vm_count = (kmalloc_get_stats().free_bytes after the cell array
* STADIUM_VM_MEMORY_PERCENT / 100) / VM_MEMORY_SIZE, floored to 1, no
ceiling (population is not knowable in advance - could be 4, could be
4000). stadium_quotas and word_slots (plus stat_promotions/stat_evictions)
are now kmalloc'd to the computed count instead of declared with a macro.
New accessor stadium_max_vm_count() replaces every STADIUM_MAX_VM_COUNT
reference, including capsule_birth.c's birth-refusal gate.
Two things found and fixed along the way:
- The existing cell-pool budget was sourced from pmm_get_stats(), which
reflects physical pages PMM hasn't handed to any subsystem yet - but
the actual allocation is kmalloc(), which draws from the separate,
fixed-size heap kmalloc_init() (M6) already carved out of PMM before
stadium_boot_init() ever runs. Budgeting against PMM's leftover and
allocating from the kmalloc heap are two different pools. Both the
cell budget and the new VM-count budget now source from
kmalloc_get_stats() instead.
- stadium_owner[] (which VM's quota owns each cell) was uint8_t, capped
at 255 slots by a compile-time assert tied to the old macro. Widened
to uint16_t (65535 slots of headroom) with a runtime clamp + log if
the computed count ever exceeds that, since there's no ceiling anymore.
Three-arch QEMU acceptance: all clean to ok>, computed VM count genuinely
differs by actual available RAM (amd64/riscv64: 50 slots at -m 1024,
aarch64: 101 slots), Stadium conservation invariant identical across all
three (resident_sum=43691 reservoir=21845 sum=65536).
logs/20260815-080526/amd64, logs/20260815-080826/aarch64,
logs/20260815-080952/riscv64.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Cursor (Captain Bob: "the only thing we need is a cursor"):
vt100_draw_cursor() draws a solid block at the terminal's current
position, called from repl.c after the prompt prints and after every
keystroke/backspace. vt100_erase_cursor() cleans up the one gap a static
cursor has -- Enter/newline moves away from the cursor cell without a
character draw ever overwriting it, which left a stray block behind
until this fix.
HB-ON/HB-OFF (Captain Bob: run a program with or without instrumentation
without rebuilding):
Converted per-tick DoE logging from a build-time flag (HEARTBEAT_DOE_LOG)
to a runtime one. doe_log_tick_row() now self-gates on g_doe_log_enabled
(default 1, matching the old default) instead of being compiled out
entirely; the call site in vm_runtime.c is unconditional. Two new FORTH
words, HB-ON and HB-OFF, flip the flag live. Removed the now-dead
HEARTBEAT_DOE_LOG plumbing: the Kconfig symbol, and the -D forwarding in
both LOADER_CFLAGS and KERNEL_CFLAGS.
Verified: three-arch clean QEMU boot + logs; dictionary word count 466
(463 baseline + ALT+TAB + HB-ON + HB-OFF, exactly the three words added
across this session); amd64 screendump confirms the cursor renders
correctly after real interactive typing.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Punch list §25 item 4.1 complete.
Replaces the round-robin hotwords cache with Stadium density-ranked
admission/eviction on the kernel side, via the §17.7 reservoir mechanism and a
kernel-side word_id -> cell_index map (no DictEntry change, dict_hash
untouched). Adds stadium_birth_hera() to close the cell-0 panic hazard,
STADIUM_WORD_HEAT_QUANTUM/STADIUM_WORD_COOL_RATE_Q48 Kconfig knobs (flagged
untuned), and a stadium_word_forget() FORGET coherence hook to close a
recycled-word_id aliasing gap.
Verified: all five hotwords_cache_* call sites in dictionary_management.c
bypassed under __STARKERNEL__; word dispatch feeds the Stadium at all three
vm_core.c physics_execution_heat_increment() sites; hosted make unaffected;
all three architectures booted to ok> with matching dict_hash
(0x3d4e1daf289da94f) and matching conservation stats (promotions=354
evictions=0, resident_sum=65536 reservoir=0 sum=65536).
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Punch list §25 item 3.2 complete.
stadium_boot_init() (src/starkernel/vm/stadium.c) sizes the global
cell array at boot from a real memory-budget query rather than a
hardcoded count: pmm_get_stats().free_bytes at the point of
allocation, times the new STADIUM_MEMORY_PERCENT Kconfig symbol
(default 1%), rounded down to whole 64-byte cells. Matches §17.6's
position (b) literally. Also allocates the header/continuation
discriminator bitmap item 3.1 declared but did not allocate. Both are
kmalloc'd and explicitly zero-filled (kmalloc does not zero).
Called from kernel_main.c immediately before sk_vm_bootstrap_parity(),
i.e. before any VM exists (§6). Failure is soft -- logs and continues,
does not halt boot -- matching the existing precedent one line below
it (VM bootstrap parity failure does the same).
Added a "Stadium: N cells (M KB)" boot console line at the allocation
site so the acceptance logs are evidence the array was actually
allocated, not just that the kernel still boots -- the same blind spot
item 3.1's uncompiled-header gap exposed.
Verified: three-architecture boot (amd64, aarch64, riscv64), all
reaching ok> with identical dict_hash=0x3d4e1daf289da94f matching the
item-3.1 baseline, and the Stadium boot line confirmed present in all
three serial logs (amd64: 74234 cells/4639 KB, aarch64: 161329
cells/10083 KB, riscv64: 76122 cells/4757 KB).
Not built here, reported per §25.0 rule 3: per-VM free lists (§22.3)
-- granted when Hera assigns quota, not this item's scope.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Punch list §25 item 3.1 re-closed after reopening.
Items 1.1 and 1.4's resolutions both explicitly named this item as
where their Kconfig symbols would be implemented, but 3.1's own stated
scope never mentioned them, so the first close missed both:
- STADIUM_CONTAINS_DEPTH_MAX (default 5) -- item 1.1's contains-chain
depth cap. No consumer yet; reap-gating enforcement is item 3.5.
- STADIUM_CAPACITY_TICK (default 1000) -- item 1.4's capacity
arbitration cadence in virtual ticks. No consumer yet; capacity
arbitration itself is not on the punch list.
Both added following STADIUM_MAX_VM_COUNT's exact pattern:
Kconfig.kernel entry, Makefile.starkernel kconfig_int +
VM_FEATURE_FLAG_VARS forwarding, starforth_config.h fallback default.
stadium.h now includes starforth_config.h and carries two more
C99-portable compile-time checks proving both symbols are defined and
sane, same discipline as the byte-count checks. Declaration only --
not inventing the consuming logic to close this out early.
Verified: three-architecture boot (amd64, aarch64, riscv64), all
reaching ok> with identical dict_hash=0x3d4e1daf289da94f, re-run after
the reopening.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Partial work toward FABRIC.md punch list item 2.2. Adds the
STADIUM_MAX_VM_COUNT Kconfig symbol (default 4, per item 1.5) wired
through Makefile.starkernel, a new CAPSULE_RUN_ERR_FLEET_FULL result
code, and a vm_registry_live_count() helper in capsule_birth.c that
counts LIVE VMs only (distinct from the existing monotonic
vm_registry_count, which never decrements on death).
NOT YET DONE: nothing calls vm_registry_live_count() yet -- the actual
birth-refusal check is not wired into capsule_birth_baby(). Not built,
not boot-tested. FABRIC.md's item 2.2 checkbox is deliberately left
unchecked; this commit exists only to save in-progress work before a
pause, not to claim the item complete.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
