LithosAnanake/FABRIC-3.10.8.md

FABRIC-3.10.8.md — Multi-core: execution plan and log

Status: IN PROGRESS. Design and rulings are in FABRIC-3.10.0.md (ruled 2026-09-25, §7). Multi-core runs ahead of O-D (MC-R6 as ruled); O-D relaunches afterwards with row path A.

Each stage:

• needs Captain Bob's explicit go;
• gets its own commit;
• gets its own three-architecture acceptance (clean qemu; amd64, then aarch64, then riscv64; foreground; visible framebuffer; one at a time; coupled images reset before each).

Evidence is named before each stage runs.

The standing acceptance sequence, unchanged from FABRIC-3.9.8.md:

• a boot to [zuse@Hera] ok> with zero UNKNOWN WORD, faults and frame corruption;
• the dict_hash set identical across ISAs;
• the Stage G interleave (A/B), byte-identical across ISAs while there is one worker core; by counts (A = 40, B = 40) once there are more (MC-R4);
• the O-A checks (observer precedence, console responsive under load);
• mint → WIREBIND → USE → 1 2 + . → 3;
• 0 bytes of idle log growth over 20 s.

No DoE execution until everything is closed (Captain Bob, 2026-09-25: "until we close everything, do not do ant DoE eecution."). MC-4's campaigns wait for that too. Stage evidence is the standard sequence plus probes, never a campaign.

Never make clean an ISA while its QEMU runs: it deletes that QEMU's QMP and serial sockets (found 2026-09-25).

1. What MC-0 must cover (traced 2026-09-25)

Everything that would break if two cores ran kernel or VM code at the same moment.

Kernel subsystems (src/starkernel/), one lock each (MC-R2), except where noted:

Subsystem	Shared state	Treatment
kmalloc, pmm, vmm	free lists, bitmaps, page tables	heap lock; PMM lock; VMM lock
kernel-Hermes	arena directory and segments, queue table, channel table, ledger, event counters	one lock
Stadium	reservoirs, cells, quotas, word rows	per-dispatch path partitioned by quota slot (a VM's own row and cells need no lock while it runs on its one core); reservoir arithmetic atomic; cross-slot operations (admission evicting another VM's cell, grants, audits) take the Stadium lock
VM registry, birth, kill, reap	registry list, names	registry lock; KILL refuses a VM running on another core
switch-signal table	slots, stamps, decision-due flag	compare-and-swap for claim/release (MC-3); lock for register/unregister
current VM, frame stack	g_switch_current_vm and friends	move to the per-core block
console	UART, framebuffer VT100 state, line prefix state	one line lock
log region, DoE region, block subsystem	rings, block chain, caches	a lock each
heartbeat	tick counters	per-core counters (MC-3); one core until then

Shared VM code (src/, vendored; runs inside every VM):

File	Global	Treatment
dictionary_management.c	sf_fc_list/sf_fc_count/sf_fc_cap/sf_cached_latest: one dictionary lookup index for all VMs, rebuilt whenever a different VM's dictionary is searched	move into VM (per-VM index). Also stops the rebuild thrash on every switch today.
word_source/starforth_words.c	g_prng_state: one PRNG stream for all VMs (accepted at Stage H)	an atomic step, so the stream stays one stream (order is nondeterministic across cores anyway, MC-R4)
physics_runtime.c	g_runtime	inventory in MC-0; per-VM or atomic
word_source/dictionary_manipulation_words.c	state_variable (STATE)	inventory in MC-0; per-VM
physics_hotwords_cache.c	g_hotwords_cache	retired under __STARKERNEL__ (item 4.1); confirm unused
word_source/ttf_words.c	font and raster cache	core 0 only (Hestia's framebuffer)

2. Staged plan

Stage	Change	Evidence (named in advance)
MC-0a	The per-core block, on one core. A per-core structure reached through each ISA's per-CPU register (GS base / TPIDR_EL1 / tp), set up for core 0 at boot. g_switch_current_vm moves into it.	Standard sequence unchanged. A probe reads the per-core pointer from a normal kernel path and from an interrupt handler, and gets core 0's block both times on all three ISAs.
MC-0b	Real spinlocks. A kernel spinlock primitive (atomic exchange, interrupts masked while held on the owning core). sf_mutex_* stop being no-ops. The §1 kernel locks are added.	Standard sequence unchanged. A probe counts every lock's acquisitions and releases through a boot and the standard sequence: counts balance, and no lock is held across a context switch or on return to the idle point.
MC-0c	Shared VM code made per-VM or atomic (§1, second table). The dictionary lookup index moves into VM.	The dict_hash set unchanged (the index is not hashed). A probe: two VMs searched alternately never rebuild each other's index. Standard sequence.
MC-0d	Stadium's dispatch path partitioned (§1).	Standard sequence; conservation holds (stadium_conserved() on every VM, the ledger audit). A probe proves the dispatch path takes no shared lock.
MC-1	Bring up the extra cores and park them halted, per ISA: amd64 (MADT, INIT-SIPI-SIPI, a position-independent trampoline below 1 MiB), aarch64 (DTB /cpus, PSCI CPU_ON), riscv64 (DTB harts, SBI HSM hart_start). QEMU gets -smp 2.	The boot reports each core online with its own per-core block; the extra cores sit halted (0 idle growth, no spin); the standard sequence unchanged.
MC-2	Observers get core-0 affinity.	With one worker core, behaviour identical to today. A probe shows no observer ever claimed off core 0.
MC-3	Worker cores claim through the shared decision: running_on with compare-and-swap, per-core idle contexts, per-core beats, wake by inter-processor interrupt.	Two workers genuinely overlapping in time on two cores. A probe counts double claims: 0. Conservation holds. G by counts. Idle worker cores halted (0 idle growth).
MC-4	DoE with cores as a factor (after O-D): per-ISA campaigns at 1, 2 and 4 cores (MC-R5).	Per ISA and core count: 18 MU-TRIAL markers, fail=0, MU-CAMPAIGN: complete.

Stop conditions (re-plan rather than push on):

• dict_hash diverges across ISAs;
• conservation goes false;
• a lock held across a switch, or an unbalanced lock count;
• a double claim;
• an idle core spinning.

3. Execution log

3.1 MC-0a — the per-core block, on one core (2026-09-25)

Change.

• include/starkernel/percpu.h (new): sk_percpu_t { self, core_id, current_vm }, with self first.
  • sk_percpu() reads this core's block: movq %gs:0 on amd64, mrs tpidr_el1 on aarch64, mv tp on riscv64.
  • sk_percpu_install() writes the register: IA32_GS_BASE via wrmsr, TPIDR_EL1, or tp.
• src/starkernel/hal/percpu.c (new): the boot core's block is one static object, not a table sized to a core count. Secondary cores get theirs as they come online (MC-1).
• kernel_main.c: sk_percpu_boot_init() runs straight after arch_early_init(), because on amd64 that call reloads GS, which would reset the base.
• switch.c: the global g_switch_current_vm is gone.
  • sk_vm_switch_current_vm(), the setter, the idle point and sk_vm_context_switch() use sk_percpu()->current_vm.
  • After resume, the context switch re-reads the block rather than trusting a pointer cached before the switch.

Probe (temporary; removed before commit).

• kernel_main.c checked, from the normal path after the Tripod came up, that:
  • sk_percpu()->self == sk_percpu();
  • core_id == 0;
  • current_vm is Hera;
  • sk_vm_switch_current_vm() agrees.
• heartbeat_tick() ran the same self-check from interrupt context on every beat.

ISA	log	normal path	core_id	current_vm is Hera	switch.c agrees	interrupt path ok / bad
amd64	logs/20260925-130335	ok	0	1	1	889 / 0
aarch64	logs/20260925-130905	ok	0	1	1	1877 / 0
riscv64	logs/20260925-131337	ok	0	1	1	1625 / 0

Standard sequence (clean build, with the probe reverted; the tree was checked byte-for-byte against the saved stage diff).

ISA	log	O-A (G, PREC, LOAD)	M7.1a hash	MINT / WIREBIND / USE / 1 2 + .	idle growth	UNKNOWN / faults
amd64	logs/20260925-131805	A=40 B=40, HHH, ok	0x99b01134c3d3049c	all ok, 3	0 B / 20 s	0 / 0
aarch64	logs/20260925-133049	A=40 B=40, HHH, ok	0x99b01134c3d3049c	all ok, 3	0 B / 20 s	0 / 0
riscv64	logs/20260925-134357	A=40 B=40, HHH, ok	0x99b01134c3d3049c	all ok, 3	0 B / 20 s	0 / 0

• The dict_hash values (Hera 0x00340a8b2c842eb7, Hestia 0x78bf28439e4a643f, Artemis 0x66886d174d5f3b5a) are identical across ISAs and unchanged from O-C.
• The ledger line matches across ISAs: held=2048, pulled=258048, returned=255263, consumed=737, conserved=true.
• No stop condition was hit. MC-0a done.