The VRAM-ranked prefix's host slabs are upload staging — read once and
freed right after — so binding them buys nothing and cost ~2 transient
VMAs each: measured PEAK maps 28,958 on the six-GPU host even with the
pin arenas in place. With the skip: 11,771, all of it the bounded LRU
ecache, which serves decode reads and stays correctly bound.
Root cause of #419's 'OOM slab': every per-slab mbind carries its own
memory policy, so bound regions cannot merge — measured ~2 VMAs per slab,
with or without MPOL_MF_MOVE. A PIN_GB=all load (19,456 experts x
slab+fslab) creates ~78k VMAs and crosses the default
vm.max_map_count=65530: posix_memalign dies with terabytes free.
The fix binds the pinned hot-store as ONE arena per layer. Experts of a
layer share a tensor shape, so a layer's pins pack at a fixed stride into
two arenas (weights + scales): 2 mbinds and a handful of VMAs per layer
instead of ~500. Slices are pre-attached to the slots before the load
loop — slab_cap covers expert_load's realloc check, so its alloc branch
never fires and expert_load itself is untouched. aslab marks arena
ownership: expert_host_release detaches instead of freeing (a REPIN
gpu-swap promotion must not free() an interior pointer), and
expert_host_ensure re-attaches the slice before reloading.
Per-slab mbind remains for the bounded allocations (dense qalloc, LRU
ecache, GPU-tier staging), now without MPOL_MF_MOVE: every bind lands
before the pread that first-touches the pages, so there is nothing to
migrate.
numa_init also gains a capability probe done right: one page-aligned
page (mbind rejects unaligned addresses with EINVAL), disabling only on
errno==EPERM — so a constrained container degrades with a message
instead of crashing later, and an EINVAL can never masquerade as a
missing capability.
The arena path activates only when interleave is actually on
(g_numa_nodes>=2, Linux, non-mmap): default builds stay byte-identical.
The grouped MoE kernels were per-row-only: GroupDesc had no group-size
fields, row_bytes() returned 0 for fmt=4, the scale buffer was hardcoded
to O floats, and a fmt=4 group that reached the generic path would have
been silently decoded as int2. This closed the GPU expert tier to every
grouped container — including the g64 quality line (#225) and the E8
lattice route (#347) whose whole point is fitting more experts in VRAM.
- ColiCudaTensor gains gs/scale_count; upload allocates O*ceil(I/gs)
scales for fmt=4 and applies the same offset->signed nibble conversion
as fmt=2 (identical packing). New ABI entry coli_cuda_tensor_upload_g
carries gs without touching the existing symbol — an old Windows DLL
missing it returns 0 and the tensor simply stays CPU-side.
- GroupDesc gains per-tensor group sizes; new grouped_hidden_g4_dual /
grouped_down_g4 apply the per-group scale inside the accumulation
(gs is required even, so a packed byte never straddles groups; gs=0
degrades to per-row, letting fmt=2 members ride the same launch).
- coli_cuda_expert_group routes any group containing fmt=4 through the
g4 kernels; pure-fmt=2 groups keep the existing paths byte-identical.
The generic fallback now explicitly rejects fmt=4 instead of decoding
garbage (#334's prevention note, made real).
tests/test_grouped_g4_cuda.cu: kernel-vs-CPU oracle over 50 trials x 3
experts — gs=64, a non-divisible tail group (200 % 64), and a per-row
member in the same launch: zero mismatches on a 5090.
make check 77/77; CPU, CUDA and MinGW builds clean.
rss_guard marked the victim slot eid=-1 under the lock, unlocked, and only then
freed s->slab. In that window the slot reads as {eid=-1, slab still valid} --
exactly the state pilot_realload's victim scan reuses first -- so a pilot worker
could claim it and pread into the slab while it was being freed: use-after-free,
or a double-free if the loader took its own realloc path.
Keep the free and the pointer/capacity NULLing inside the critical section, so
'slab valid' and 'slot reusable' are never simultaneously observable. The lock is
held across a free() (microseconds); workers only take it briefly for scan+reserve.
Reproduces on dev with a SINGLE pilot worker (rss_guard runs on the main thread
while the pilot worker runs in the background), whenever the RAM guard is active
(RSS_GUARD_GB, or any resolved g_ram_budget_gb).
make check 83/83, native + portable builds 0 warnings.
Under O_DIRECT the expert *weights* are read with the direct fd (bypassing the
page cache), so a POSIX_FADV_WILLNEED on them warms pages the demand read never
consumes -- pure wasted readahead on the disk, the scarcest resource when
streaming. The .qs scales are ALWAYS read buffered (pread on the normal fd), so
keep their WILLNEED. This only changes hint-only PILOT (PILOT=1, PILOT_REAL=0)
combined with DIRECT=1; fadvise is advisory, so output is bit-identical.
Prepared, not yet measured: needs a real NVMe + full model to A/B cold-stream
tok/s (PILOT=1 DIRECT=1, with/without this patch, TEMP=0). See #441.
pin_load computed npin from the RAM budget FIRST, then carved the
VRAM-ranked prefix out of those npin slots. With CUDA_RELEASE_HOST the
prefix's host slabs are freed right after upload — so on a multi-GPU
host the top-ranked experts consumed the RAM budget without occupying
RAM, and the CPU tier pinned only the leftovers. Measured on 6x RTX 5090
(251 GB): 9,280 VRAM + only 1,721 RAM pins (32.5 GB warm) on a box whose
RAM fits ~10k more — the cold tail then paid disk on every token and the
hit rate ceilinged at 99.0% forever.
Move the VRAM budget estimate above the npin finalization and make the
release-destined prefix ADDITIVE to the RAM-derived count. Same box,
same env plus the fix:
[PIN] placement: 9,280 VRAM + 10,176 RAM (192.5 GB warm)
expert hit rate 100.0% (pin 100.0% + lru 0.0%) — disk 0
1,024-token greedy decode: 3.62 -> 6.21 tok/s (+72%)
warm late segment (t=768-1024): 5.11 -> 5.73 tok/s (+12%)
prefill: 10.4 -> 8.8 s
The whole-run gain is the LRU warmup penalty disappearing (full
residency from the first token); the late-segment gain is the steady
~0.9%-miss disk residue recovered. Non-release configs are untouched:
prefix_est stays 0 and the arithmetic reduces to today's exactly.
Re-derivation of e7/disk-class-instr @ de6dd6d (base caa49f7) onto
origin/dev @ 61004dc, after PR #391 split c/glm.c into c/colibri.c plus
quant.h/sample.h/kv_persist.h/telemetry.h/grammar.h. Semantic equivalence,
not a copy: same events, same accounting, re-sited onto the new tree.
Placement: colibri.c, unchanged from before the split. telemetry.h (#391)
is the dashboard/stats module (HWINFO/TIERS/EMAP/HITS protocol lines +
usage persistence) — prof_report(), expert_load_impl(), moe(), g_prof_io
and g_edisk_ns all stayed in colibri.c, so DISK-CLASS's aggregation and
printing follow them there. No relocation needed, no DEVIATION.
Read path: #362 (prefetcher-v3, 22509fc) turned out to be testbed-only
scope per its own merge message ("glm.c untouched") — confirmed zero
c/glm.c changes in that merge's diff. The seven expert_load() call sites
this patch touches (pipe_worker, expert_host_ensure, moe()'s OMP miss
loop, pilot_realload, repin_pass_limit, pin_load x2) are structurally
identical to the pre-split tree; the demand flag re-attaches at the same
sites with the same semantics (1 only at moe()'s own PIPE/OMP miss path,
0 everywhere else), so DISK-CLASS still counts demand loads only.
One real drift, unrelated to #362: #417 (cfcc742) fixed the exact "Metal
pre-routed FASE A never bumps the real elast/eaccess_clock" defect this
feature's comments described as a documented, deliberately-unfixed
upstream issue — the real clock now ticks in FASE A too. The private
elast_dc/eaccess_clock_dc clock is kept anyway: its job was never only
to route around that freeze, it also snapshots pre-bump state so a
call's own routing bump can't contaminate its own classification, and
keeping DISK-CLASS's bookkeeping fully separate from stock elast state
is what makes "byte-identical with PROF=0" provable by construction
instead of by argument. Code comments referencing the old defect are
updated to reflect the fix (historical note + #417/cfcc742 pointer)
rather than describing a bug that no longer exists.
Gates: make glm METAL=0 and METAL=1 both clean, zero warnings (matches
stock 61004dc, also built clean with zero warnings for comparison).
make test-c: 0 failures. make test-python: 77 tests, OK.
Authored by Fable 5 in Claude Code, analysis in partnership with
@Monotophic.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
First increment of the #431 plan (device router -> indirect kernels ->
one-graph decode). At decode (S=1) on the pipe2 path, the router runs on
the layer's home device: a tiny E x D logits GEMV + sigmoid, then a
single-thread selection kernel that clones moe()'s plain routing path
verbatim — bias-augmented top-K by choice with strict-> tie-breaking,
weights from the raw logit, route-level TOPP truncation, norm_topk,
routed_scale. Results pack into one scratch buffer and come back in a
single ~68-byte D2H; moe() consumes them through the same pre-routed
shortcut the Metal layer-CB uses (g_pre_idx, #417 bookkeeping included),
so usage/heat/recency accounting is identical to the CPU router.
Structural value: routing becomes available ON the device timeline,
which is what PR-B (indirect expert kernels, static topology) and PR-C
(whole-decode CUDA Graph) build on.
Opt-in, default off. Gated to the plain routing path — CACHE_ROUTE,
ROUTE_P and ROUTE_TRACE keep the CPU ranking they need; any upload or
launch failure falls back to the CPU router silently. Router weights
(E x D f32, ~6.3 MB/layer) upload lazily to the layer's home device.
tests/test_router_cuda.cu: kernel-vs-CPU-reference oracle over 200
random trials (mixed TOPP/norm_topk/scale): 200/200 exact selections,
zero near-tie flips, zero weight mismatches on a 5090.
expert_load's fslab-OOM unwind freed s->slab via compat_aligned_free without
coli_metal_unregister -- a pre-existing gap on main/dev (validator-confirmed
during E4) that leaves a stale g_slabs entry over freed memory, letting
resolve() hand the GPU a dangling pointer. Under COLI_METAL_RESSET=1 the
exposure is strictly longer-lived: the wrapped buffer would stay a permanent
residency-set member over the freed pages instead of stock's transient
last-command-buffer window. Ported from e4/metal-heap validator fix 6753225,
adapted to dev's non-heap code shape (no coli_metal_heap_free wrapper --
plain unregister-before-free).
The uring_load_add analog (E4 audit round-2 insurance) is deliberately not
carried: that arm is #ifdef __linux__-gated while COLI_METAL is macOS-only,
so it is dead code on every real build target, and unlike E4 this branch has
no allocation-path reason to touch the function.
Reachable only through allocation failure mid-load; verified by inspection
and clean builds (no OOM-injection harness in tree). SUMMARY.md item 10
updated to "carried on this branch".
1. REQUIRED (backend_metal.mm): no Metal call runs under g_slab_mtx anymore.
The set mutations (addAllocation/removeAllocation/commit) and the dirty
flag moved to a dedicated g_resset_mtx; coli_metal_register/unregister do
their g_slabs bookkeeping under g_slab_mtx exactly as stock, then call
resset_add/resset_remove after dropping it (still before returning, so
unregister's remove+commit still lands before the caller frees the host
memory). The original shape -- commit under the slab lock the parallel OMP
loader threads contend on -- was structurally identical to the mutex-over-
live-Metal-call bug E4's audit round 2 fixed, the leading suspect for its
replicated +12s expert-disk regression. The register->flush->resolve
happens-before argument survives the split: resset_add completes inside
coli_metal_register before it returns, the engine cannot dispatch an
expert before its load returns, and add/flush are serialized by
g_resset_mtx (comment at resset_add). The two mutexes are never held
together, so no lock-order hazard exists.
2. REQUIRED (backend_metal.mm, backend_metal.h, glm.c): the resset_flush
cost in moe_submit -- deliberately outside the g_t_setup window so the
A/B harness counters keep their meaning -- was invisible. New
g_t_resset_flush accumulator timed around the flush, exported via
coli_metal_resset_stats(), printed by profile_print as a separate
gate-on-only "METAL-RESSET: flush" line (mirrors E4's METAL-HEAP line;
the METAL: line the harness parses keeps its exact format; stock output
byte-identical -- the stats call returns 0 with the gate off and the
whole block sits in the pre-existing #ifdef COLI_METAL arm). Register-
side add/remove costs land in the existing t_ewait window; comment at
resset_add says so instead of a second counter.
3. REQUIRED (SUMMARY.md; the moe_submit commit message was already reworded
in place, pre-push): corrected two false attributions -- the hazard-
tracking and thread-safety statements were credited to the SDK header,
which is silent on both; the actual source is Apple's online
MTLResidencySet class reference and residency-set adoption guide
(fetched 2026-07-18). Note: the scaffolding commit's message was checked
and contains no such claim, so it was left untouched.
4. DOC (SUMMARY.md): the pre-existing fslab OOM-unwind bug (glm.c ~1868-73,
frees s->slab without unregister) has a strictly longer-lived exposure
under E5 (permanent set member vs stock's transient per-CB declaration).
Out of scope here; the upstream PR built from E5 must carry the one-line
fix (reference: E4 branch commit 6753225).
The has_mtp completeness probe checked for `mlp.experts.255.down_proj.weight`,
which only exists when n_routed_experts == 256. REAP-pruned checkpoints (and any
MoE with a different expert count) have fewer experts, so the probe spuriously
reported has_mtp=0 and disabled MTP speculative decode even though the head was
present and complete. Probe `mlp.experts.<n_experts-1>` instead.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Rename glm.c → colibri.c and extract four self-contained modules
into header-only files (same pattern as st.h/tier.h/grammar.h):
quant.h (672 lines) — SIMD matmul kernels, quantization
sample.h (143 lines) — RNG, top-p sampling, stop-set
kv_persist.h (121 lines) — .coli_kv disk persistence
telemetry.h (189 lines) — dashboard protocol, stats, usage
Main engine file shrinks from 6588 to 5396 lines (−18%).
Build system: primary target is now colibri$(EXE); `make glm`
remains as a phony alias for backward compat. CI, setup.sh,
coli CLI, and all 10 test files that include the engine are
updated. make check passes (C + Python, 73 tests, zero warnings).
FABIOTESS