Skip to content

feat(llama-cpp-localai-paged): paged KV cache llama.cpp backend + cross-request prefix sharing + GB10 decode optimization [WIP]#10462

Draft
localai-bot wants to merge 145 commits into
masterfrom
worktree-feat+paged-attention
Draft

feat(llama-cpp-localai-paged): paged KV cache llama.cpp backend + cross-request prefix sharing + GB10 decode optimization [WIP]#10462
localai-bot wants to merge 145 commits into
masterfrom
worktree-feat+paged-attention

Conversation

@localai-bot

Copy link
Copy Markdown
Collaborator

Status: draft / WIP - opened to track ongoing GB10 enterprise-serving work. Large branch (kernel experiments + analysis + the shippable feature); will be curated before any merge.

What this is

Vendored, opt-in paged KV cache + cross-request prefix sharing for the llama.cpp backend, plus GB10 (consumer Blackwell, sm_121) decode-path optimization and the supporting analysis. All paged behaviour is gated by LLAMA_KV_PAGED (env) / the kv_paged server option and is off by default - stock builds are byte-identical.

Shippable feature pieces

  • backend/cpp/llama-cpp/patches/paged/0001-0011 - vendored llama.cpp patch series, applied behind the LLAMA_PAGED build flag (patches/paged/, default on; LLAMA_PAGED=off gives a clean upstream checkout). Isolated in prepare.sh + Makefile with a sentinel guard against double-apply.
  • grpc-server.cpp - kv_paged per-server option (0005) + cross-request prefix share wired into update_slots (0008).
  • core/backend/hardware_defaults.go, pkg/xsysinfo/gpu.go - hardware-aware default consolidation.

Key results (measured on DGX Spark / GB10, Qwen3-32B NVFP4)

  • Prefix sharing (RAG / system-prompt fan-out): the cross-request cache reaches the server - concurrent shared-prefix requests skip recompute, 15-25x burst-wall prefill reduction (K=16/32), reuse confirmed (ref_cnt=K, suffix-only prefill).
  • Decode kernel: an in-kernel block-table read (0009) deletes the per-step gather regression; routing the GQA-grouped tile kernel by default (0011) brings paged decode to stock parity (within 1.8%), growing to -6.1% at 16k ctx. Token-correct (CPU byte-identical, GPU within the CUDA batch-shape non-determinism band).
  • Honest framing: the earlier "6x decode gap vs vLLM" was a measurement artifact (the pre-0009 gather regression + a warmup/server number). The real steady-state decode is GPU-bound at the LPDDR5x bandwidth wall (~50% irreducible weight-read floor), ~1.2x from vLLM at the kernel level. Remaining throughput headroom is at the scheduler/serving layer, not the kernel.

Analysis docs live under backend/cpp/llama-cpp/patches/paged/*.md and backend/cpp/llama-cpp/paged/*.md.

Next

  • Scheduler/serving lever (continuous batching + chunked prefill + paged-KV capacity) for aggregate throughput.
  • Correctness hardening (mask-pad invariant assert) + CUDA-graphs confirmation (graphs are already ON in serving).

Not for merge as-is

This branch also contains banked W4A16/Marlin kernel experiments and NVFP4/MXFP4 quality analysis that informed the direction but are not part of the feature. Those will be dropped/split before merge.

mudler added 30 commits June 19, 2026 08:26
Host-side paged-attention block manager ported faithfully from vLLM V1
(block_pool.py, kv_cache_utils.py, single_type_kv_cache_manager.py):

- KVCacheBlock + intrusive LRU FreeBlockQueue (O(1) middle removal)
- BlockPool: get_new_blocks / touch / free_blocks eviction ordering /
  cache_full_blocks / lazy eviction on reuse
- PagedKVManager: on-demand allocate, block_table, slot arithmetic
  (slot = block_id*block_size + offset), free
- Prefix caching: chained block hashing + find_longest_cache_hit
  (first-miss stop), enabling automatic cross-tenant prefix sharing

Pure C++17, zero ggml/llama.cpp dependency, unit-tested to vLLM behavioral
parity (4/4 suites green). Parity is on algorithm/behavior, not hash bytes.

Phase 0 of docs/superpowers/plans/2026-06-19-paged-attention-llamacpp.md.
Phases 1-5 (ggml storage, gather-to-scratch read path, Gate 0 correctness,
benchmark wins, prefix-share serving) follow.

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Validate the paged KV read/write path at the ggml-op level, driven by
PagedKVManager:

- write: ggml_set_rows(pool, k_src, slot_mapping)  scatter K rows by slot
- read:  ggml_get_rows(pool, gather_idx)           gather a seq's slots into
         contiguous scratch (the tensor an attention kernel consumes)

The test forces a non-contiguous, out-of-order physical block layout
(allocate seqA+seqB, free seqA, reallocate seqC -> blocks [2,1,5]) and
proves gather(write(x)) == x plus cross-sequence isolation in the shared
pool. This de-risks the central question (does slot-addressed paged storage
round-trip correctly through ggml) before the llama-graph integration.

Pool is statically allocated via ggml_backend_alloc_ctx_tensors, mirroring
how llama.cpp allocates its KV cache. CPU backend, no new ggml op.
Built against ggml from the vendored llama.cpp checkout.

Phase 1 of docs/superpowers/plans/2026-06-19-paged-attention-llamacpp.md.

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Retire the central numeric risk from the design: feeding gather-to-scratch
KV (a sequence whose blocks are non-contiguous in the shared pool, [2,1,5])
into ggml's standard attention ops produces correct attention.

Path under test: set_rows write -> get_rows gather (K and V) ->
mul_mat(K,Q) -> soft_max_ext -> mul_mat(V^T, probs). Result is compared
against an independent host-computed softmax attention over the same K/V/Q.
Max abs error ~7.5e-08 (n_kv=48, d=8, n_q=4).

This proves the paged read path is numerically sound on CPU with no new
ggml op. Remaining: wire build_attn_paged into llama-graph.cpp and validate
Gate 0 (token-identical greedy generation in a real model).

Phase 2 (core) of docs/superpowers/plans/2026-06-19-paged-attention-llamacpp.md.

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Quantify the two multi-tenant wins that are properties of the host-side
block model (vLLM-parity), independent of the in-model compute path:

  WIN 1 concurrency capacity @ 512-block budget
    contiguous (reserve n_ctx/seq): 4 sequences
    paged (on-demand blocks):       37 sequences
    --> 9.2x more concurrent sequences

  WIN 3 cross-tenant prefix sharing (32 tenants, 1024-tok shared prefix)
    prefix-cache OFF: 2176 physical blocks
    prefix-cache ON:  192 physical blocks
    --> 11.3x less KV memory

WIN 2 (throughput) is deliberately reported as PENDING: it requires the
paged gather-read path wired into llama-graph.cpp (Gate 0) and is not
measurable at the allocation layer. The win-1 baseline is per-sequence
n_ctx reservation (stream mode); llama.cpp's unified cache already shares
one pool, so the honest win there is on-demand sizing + prefix dedup.

Phase 3 (partial) of docs/superpowers/plans/2026-06-19-paged-attention-llamacpp.md.

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Capture verified state (P0 manager parity, P1 ggml write/gather, P2 attention
numerics 7.5e-08, P3 capacity 9.2x + prefix-sharing 11.3x) and the exact
remaining work: wire build_attn_paged into llama-graph.cpp and validate
token-identical generation on Qwen3-0.6B (Gate 0), then win-2 throughput.

Records the integration seams (create_memory, find_slot, get_k/get_v,
build_attn, mask) and the honest caveats (unified cache already shares a
pool; vLLM's classic kernel is deprecated) so the next session starts warm.

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
…KV placement

Wire paged, non-contiguous fixed-size BLOCK placement into the real
llama.cpp KV cache (find_slot), behind env LLAMA_KV_PAGED, and validate
Gate 0 on a real GGUF: Qwen3-0.6B greedy generation is TOKEN-IDENTICAL to
the contiguous cache while its KV is physically scattered across permuted
blocks (cells 0-15, 144-159, 32-47, ...). Proven non-contiguous via
LLAMA_KV_PAGED_DEBUG, not a silent fallback.

This retires the correctness premise of paged attention IN THE MODEL (not
just at the ggml-op level): attention is invariant to physical KV placement,
because reads use per-cell pos/seq metadata for masking. The patch lives at
patches/0001-paged-kv-block-placement.patch (against llama.cpp 0253fb21f).

Scope: storage/placement layer, single sequence. Remaining (P4): the
gather-read compute path (attend only a seq's own blocks) for the throughput
win, and the multi-sequence driver. README updated with repro + status.

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Captures the full dgx.casa investigation: Q8/F16/vLLM baselines, concurrency
sweeps, paged-patch (no concurrency effect), nsys+code root-cause (MoE int8
MMQ on Ampere-class tensor cores = 74.5% compute, no FP8 path), and the
lever plan.

Measured wins:
- Lever 1 (MXFP4 / Blackwell FP4 path): decode +50-66% over Q8, prefill
  plateau +66% (2200->3650). MXFP4 decode beats vLLM FP8 at B=1 (83 vs 48),
  near-parity B=8. Prefill still plateaus (fused-MoE-GEMM gap).
- Lever 2 (ubatch): saturates at 2048; ceiling is the kernel, not batch.

Designed (not built): Lever 3 fused FP4/FP8 MoE grouped GEMM, Lever 4 FP8
GEMM (needs ggml_mul_mat_ext scale plumbing), Lever 5 tcgen05 kernels, and
the complete paged attention (on-demand alloc + gather-read + continuous
batching + prefix sharing). Honest scope: each is multi-week kernel/systems
work.

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
On NVIDIA Blackwell consumer GPUs (sm_120/121, incl. GB10/DGX Spark) a larger
physical batch (n_ubatch) materially lifts MoE prefill throughput - measured on
a GB10 with Qwen3-30B-A3B to lift the prefill ceiling and saturate at ~2048.

When a model config leaves `batch:` unset, EffectiveBatchSize now picks 2048 on
Blackwell instead of 512; explicit `batch:` always overrides. Detection is a
shared, cached Go helper (xsysinfo.IsNVIDIABlackwell, nvidia-smi compute_cap
>= 12). Logic is isolated in core/backend/hardware_defaults.go and applied at
the common ModelOptions builder, so it covers the C++ llama.cpp backend too.

Measured (GB10, Qwen3-Coder-30B-A3B MXFP4): prefill ub512 2994 -> ub2048 3316
t/s; saturates past 2048. Also recorded in the DGX gap plan: 4-bit quant alone
captures the decode win (Q4_K_M 93.5 >= MXFP4 86.4 t/s), MXFP4's only edge is
prefill via Blackwell FP4 tensor cores.

Tests: hardware_defaults_internal_test.go; existing NBatch specs pinned to the
no-Blackwell branch for determinism.

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Prefill doesn't scale with bigger single prompts (attention O(N^2)); real gap
is batched MoE prefill (B=32: 27x vs vLLM, ~22 effective TFLOP/s). nsys pins
Lever 3 target: mul_mat_q<MXFP4> MoE GEMM 37% + un-fused act-quant 8%; native
FP4 MMA already engaged, inefficiency is the per-expert thin-tile scheduler.
Q4_K_M matches MXFP4 on decode (decode win is generic 4-bit); MXFP4's only edge
is prefill. Auto-ubatch=2048 on Blackwell shipped (PR #10411).

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
…m ggml issue draft

Plan A (Lever 3): phased path to FP4 MoE GEMM parity — cheap tweaks, act-quant
fusion, then the real lever (tcgen05/CUTLASS grouped GEMM), full-model FP4.
Plan B (paged attention): on-demand pool, gather-read + Gate 0, continuous
batching, prefix sharing; benchmark in memory-pressured/mixed-length regimes.
Upstream issue draft: GB10 numbers, nsys profile, ruled-out config knobs,
tcgen05 proposal.

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
static_assert(nwarps*tile_C::I == mmq_y) locks nwarps=8 for mmq_y=128; can't
raise occupancy without co-scaling mmq_y (blows Blackwell smem). MMQ kernel is
not freely tunable -> parity needs the tcgen05/CUTLASS rewrite, not knobs.

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
…s from-scratch

No tcgen05/CUTLASS grouped-GEMM MoE kernel exists upstream (merged/in-flight/
draft); CUTLASS not a dep; no fork has one; activation-quant gather already
fused. Matching vLLM needs a from-scratch tcgen05 grouped GEMM (months,
maintainers deferring to cuTile). No tractable patch closes the 27x.

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
…ttention

Numbered patches under backend/cpp/llama-cpp/patches/ applied in order against
the pinned LLAMA_VERSION (build hook in the llama.cpp: target). Each phase is one
small, independently-buildable patch so the work rebases cleanly across llama.cpp
bumps (anti-drift). README defines the series (0001 vendor manager -> 0006 prefix
caching) + the regen workflow.

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
First patch of the stacking series. Adds src/paged-kv-manager.{h,cpp} (the
CPU-verified vLLM-parity block manager) + CMake entry. No behavior change.
Generated against the pinned LLAMA_VERSION; applies clean.

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
…ical

find_slot places a sequence's tokens at permuted non-contiguous blocks; greedy
generation is token-identical to stock (verified on Qwen3-0.6B at the pin),
branch confirmed firing. Default off. The placement substrate for the gather-read.

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Every edit mapped (gather-index graph input mirroring k_idxs; gather K/V/mask by
one aligned index; n_kv compaction; gated so stock stays byte-identical) with
the token-identical gate and the known risks (mask transpose layout, v_trans).

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
… single-stream first

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Prefill 6-48x behind and does NOT scale with B (kernel-bound, paging can't fix).
Decode: we win at B=1; 2.5-3.7x behind at B>=8 - THAT concurrency gap is the
engine's domain (0004 pool + 0005 continuous batching target it). Baseline for
the series to improve on.

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
…is 54.6% MoE GEMM too

Decode-dominated B=64 nsys: mul_mat_q<MXFP4> 54.6%, attention only 19.8%. Both
phases are FP4-MoE-kernel-bound (Lever 3). The paged series cannot close the vLLM
gap in either phase; its real value is capacity + prefix-sharing, not tok/s parity.

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
…Lever 3)

The only work that closes the vLLM gap on Blackwell: mul_mat_q<MXFP4> is 37%
prefill + 54.6% decode-B64 GPU time; paged attention can't touch it (proven).
Scaffold (builds clean on GB10, default byte-identical): fp4-grouped-moe.{cuh,cu}
entry + gated hook in ggml_cuda_mul_mat_id (env GGML_CUDA_FP4_GROUPED), always
falls back to MMQ for now. Design doc has the CUTLASS/tcgen05 implementation
phases + parity harness + the dense-path follow-up (#28).

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
…PP 7.6-32x)

vLLM W4A16 vs llama Q4_K_M dense: prefill 7.6-32x behind (llama plateaus ~765,
vLLM scales to 24.4k); decode ~parity at B=1 (weight-bandwidth-bound), 2.2x at
B=64. Full NVFP4 (W4A4) hangs on this vLLM/GB10 stack - W4A16 used. Decision:
the Lever-3 kernel track must ALSO deliver a non-grouped FP4 dense GEMM, not just
the MoE grouped GEMM (dense GEMM is the simpler first kernel to land).

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
…n grouped)

Benchmark confirms dense prefill 7.6-32x behind too, so the kernel track needs a
non-grouped FP4 dense GEMM (simpler, land first) + the MoE grouped GEMM. Both
share the e2m1 block-scaled collective; dense is grouped-with-one-group.

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
…ry flag lever exhausted

Confirms parity (dense+MoE, both phases) is strictly the FP4 tensor-core kernel;
no config/flag shortcut remains.

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
…line

Researched: W4A4 hangs on GB10 because FlashInfer ships no FP4 cubins for
sm_120/121 (all datacenter Sm100a); dense mm_fp4 is gated-off/returns-zeros on
consumer Blackwell, and the FlashInfer FP4 autotuner spins on the first forward
pass. Not a misconfig - dense W4A4 inference isn't validated on sm_121. W4A16
(4-bit weight / 16-bit act, Marlin) vs llama Q4_K_M is the correct apples-to-
apples (same quant class) AND the fast path. Removed the misleading 'W4A4 would
be faster / lower bound' framing. Sources: vllm #30163/#26381, flashinfer
#2577/#3294, cutlass #3096.

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Key corrections: (1) vLLM 24k is AGGREGATE; single-stream roofline ~3300 t/s
(BF16) / 6600 (FP4). (2) GB10 is 1:1:2 BF16:INT8:FP4 - INT8 == BF16, only FP4 is
2x. (3) Measured: dense int8-MMQ at 21% of ceiling, MoE FP4-MMQ at ~5% - both
EXIST, just untuned for Blackwell. Strategy: to MATCH vLLM, tune MMQ or build a
Marlin-style W4A16 BF16 GEMM (FP4 NOT required); to BEAT, fix the existing FP4
MMA on sm_121 (build/miscompile, not greenfield). Dropped the tcgen05 grouped
GEMM rewrite. Cheap next test: dense MXFP4 quant + existing FP4-MMA.

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
… (~17% of ceiling)

MXFP4 dense moves prefill off int8-MMQ onto the FP4-MMA path (existing kernel) for
a free 1.44x - shippable as a Blackwell dense-quant recommendation. But it's ~17%
of the FP4 roofline, so the FP4-MMA kernel is itself untuned: ~4-6x still in the
kernel. Sharpens the target to TUNING the FP4-MMA (serves dense+MoE, only path to
beat vLLM). Marlin-style W4A16 BF16 is the alt to match on the BF16 ceiling.

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
…ever

Per-user decode is at parity without spec-dec (10.2 vs 11.7, bandwidth-bound).
vLLM's per-user speed = speculative decoding (lossless, target-verified). GB10 is
best-case (bandwidth-bound + idle compute); llama.cpp spec-dec measured 2.9x on
dense Qwen2.5-32B. Qwen3-32B has no native MTP - use Qwen3-1.7B draft or EAGLE3
head. Recommendation: make spec-dec easy for dense >=14B on Blackwell (keeps
Q4_K_M quality, no kernel). Prefill-kernel + continuous-batching are separate
(TTFT / aggregate). Our own DGX run pending (box rebooted, llama-cli hangs).

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Phase 1 (config, PR #10411, DONE): VRAM-scaled n_parallel + Blackwell batch.
Phase 2: paged KV (PR #22569, ~9.5x concurrency). Phase 3: chunked prefill +
n_batch/ubatch split. Phase 4: batched-GEMM kernel tuning. Phase 5: backend
sampling. Cross-cutting: spec-dec for dense.

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
… plan

Decisive DGX experiment: rebuilt with -DGGML_CUDA_FORCE_CUBLAS (it's a compile
#ifdef, not the runtime env we'd been setting - so prior 'cuBLAS no-op' tests
never engaged it). Real result: cuBLAS is SLOWER than MMQ for dense Q4 (pp2048
690 vs 750) and runs an Ampere cutlass_80_tensorop kernel - CUDA-13 has no sm_121
GEMM, falls back to sm_80. So both MMQ and cuBLAS sit at ~46 TFLOP/s; no library
shortcut to the 213 ceiling on GB10. Confirms a hand-tuned sm_120a kernel is
required. Added the phased W4A16 Marlin-style implementation plan (P0 harness ->
P5 enable) as the committed multi-week build; corrected the cuBLAS note.

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
mudler added 7 commits June 26, 2026 03:51
…-vs-npl plots

Public deliverable for the patch-0018..0023 f32 bit-exact paged-attention ship:
the apples-to-apples NVFP4 decode benchmark (llama.cpp paged 0023 vs vLLM 0.23.0
on GB10 / DGX Spark, matched weights, CUDA graphs ON both sides).

- final_benchmark.csv: clean 8-column plot-ready schema
  (model,engine,npl,decode_agg_tps,decode_perseq_tps,prefill_tps,ttft_mean_ms,peak_gb),
  16 rows (2 models x 2 engines x npl 8/32/64/128).
- QWEN36_NVFP4_BENCH.md: embed the two decode-vs-npl plots; add the
  internal-consistency note (decode_agg vs perseq*npl is TTFT-governed, holds on
  both engines, no stale-baseline carry-over).
- decode-vs-npl PNGs (one per model), llama vs vLLM, per-point llama-%-of-vLLM labels.

Headline (measured, nothing pre-assumed): dense llama 90-117% of vLLM decode
(ahead at npl8), MoE 77-83%, at higher precision (f32 GDN state + q8 act vs vLLM
bf16 GDN + w4a4) and 1.5-3x lower unified memory (on-demand paged KV vs vLLM's
flat ~107 GB pool).

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
…(benchmark finding)

The final benchmark exposed TTFT as the weakest number (dense npl128 903s vs vLLM
6-18s, decode-first budget throttling burst-prefill) plus a concrete paged-pool
burst-degradation bug (post-burst low-npl prefill collapses 507->65 t/s; decode
unaffected). Highest-value serving fix; decode + memory already strong.

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Earlier text claimed bf16 = vLLM's own precision; that was a refuted byte-gate
draft re-surfacing. The settled finding (BITEXACT_VS_VLLM.md, proven 3 ways) is
that vLLM keeps the gated-DeltaNet TEMPORAL state in f32 (only its conv state is
bf16). So bf16 temporal is BELOW vLLM's recurrent precision, not a match; and at
equal f32 precision llama's recurrence already beats vLLM (84.6% vs 82.4% peak).

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Empirical probe on q36-27b-nvfp4 @npl128 (build f7409c2, patch 0023):
- attention KV cache default is ALREADY f16 (K/V f16) -> --cache-type f16 is a
  no-op; q8_0 within noise -> KV dtype is not a decode lever
- nsys node-trace decode budget: f32-glue (norms/elementwise/activations/attn,
  excl. SSM recurrence + NVFP4 GEMM) = 28.7 ms = 8.4% of step (40.9 ms = 12%
  incl. the non-FP4 cublas GEMM)
- f16 realistically recovers ~11-16 ms of the ~27 ms/step gap = ~40-60% of the
  8.2% residual -> ~95-96% parity, not a full close; non-bit-exact opt-in only

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Synthesize the GPU kernel-budget probe with the read-only glue source
map. Add (4) the implementation cost - llama has no model-compute-dtype
knob, the residual stream is F32 by construction (ggml_mul_mat hardcodes
F32 output), so f16 glue is not a flag but an opt-in multi-file change
(norm.cu f16 kernels + f16 residual stream). Add the final verdict:
precision is not the dominant cause of the 8% residual (83% of the step
is already f32/W4A4-matched), f16 recovers only 40-60% of the gap and is
non-bit-exact, so do not build it as the default; ship the 95%-bit-exact
f32 plateau and target the structural cublas/graph-launch ~3-4% instead.

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
… paged-pool burst bug as first build target

Synthesis of the four read-only/GPU investigations (A MoE grouped-GEMM,
B cublas lm_head, C TTFT/paged-pool burst, D dense CUDA-graph):

- A: llama already has the sorted-grouped-FP4-MMA GEMM (higher tier than
  vLLM's GB10 W4A16 Marlin fallback); standalone bit-exact kernel win is
  bounded on this bandwidth-bound a3b model. Keep down_proj quantize
  retune (M1) as a cheap bank-shot; fold the decode-graph (M2) into a
  later shared GDN+MoE decode-graph project.
- B: lm_head is BF16 (not FP4), nvjet already ~72% of peak HBM; bit-exact
  ceiling <1%, the only big win (NVFP4 head) is non-bit-exact and unfair
  vs vLLM. Dead end. Rank last.
- C: paged-pool burst-degradation BUG (Part 2) is a true correctness
  defect (prefill collapses 507->65 t/s after a burst, restart cures it):
  reclamation gap on partial seq_rm + free-queue fragmentation. Plus the
  static decode-first budget (Part 1) explains 903s/213s burst TTFT and
  the chunked-interleave fix.
- D: f32 dense CUDA-graph is STABLE (<1%, no bimodality); the brief's
  bimodality was the shelved BF16 SSM path. Closed.

First build target: the paged-pool burst-degradation bug fix (Fix-1
truncate-on-partial-seq_rm + Fix-2 defrag-on-empty + Fix-3 release-on-slot-
completion). Small, localized, default-off byte-identical, crisp repro
(npl64 burst then npl8: prefill within 10% of fresh + num_free restored).

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
…se) (patch 0024)

Fixes the paged-pool burst-degradation bug (OTHER_PATHS_INVESTIGATION.md section C
Part 2): on a long-lived llama-server with LLAMA_KV_PAGED=1, a high-fan-out prefill
burst strands KV blocks in the host-side paged pool, so a later lower-npl prefill
draws from a depleted/fragmented pool and its throughput collapses (the benchmark's
"restart per npl" crutch). Decode is unaffected. The fix changes only host-side
block accounting and placement, never KV values or compute, and is gated behind
LLAMA_KV_PAGED (LLAMA_PAGED_NO_RECLAIM=1 restores the pre-fix behavior).

Fix-1 reclaim trailing blocks: PagedKVManager::truncate(seq, n_keep) frees every
block beyond ceil(n_keep/bs) (ref-counted); called from llama_kv_cache::seq_rm for
the p1==MAX && p0>0 partial-tail case so the manager tracks the kv-cache exactly.
Fix-2 defrag on empty: when the pool is fully idle, defrag_free_pool() relinks the
free queue into ascending block-id order (FreeBlockQueue::rebuild), preserving
content-cache hashes.
Fix-3 release on slot completion: server_slot::release() issues prompt_clear()
under the paged engine so a finished-idle slot returns its blocks promptly.

Validation (DGX GB10, q36-27b-nvfp4 = qwen35 hybrid; HEAD f7409c2 = patch 0023):
- Bit-exact: greedy md5 identical across paged off / paged on / paged on+NO_RECLAIM
  (5951a5b4d624ce891e22ab5fca9bc439), == the 0023 baseline. test-backend-ops
  unaffected (no ggml op touched).
- Host unit test: truncate reclaims exactly 16 trailing blocks; defrag restores
  ascending popleft order. UNIT PASS.
- Model A/B (one binary, NO_RECLAIM): fragmentation prefill ratio 0.944 -> 0.998;
  64 idle slots strand 2048 blocks, reclaim returns the pool to fresh (2527).
- Server A/B (FRESH-npl8 -> BURST-npl64 -> POST-npl8): POST-npl8 prefill collapses
  488 -> 44 t/s with NO_RECLAIM (the bug; investigation saw 507 -> 65), restored to
  532 t/s (fresh 525, within 1%) with the fix. Paged release-log count 17 -> 96
  (Fix-3 fires per slot completion). Canary tokens identical fresh-vs-post in both
  arms (bit-exact serving).

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
@mudler mudler changed the title feat(llama-cpp): paged KV cache + cross-request prefix sharing + GB10 decode optimization [WIP] feat(llama-cpp-localai-paged): paged KV cache llama.cpp backend + cross-request prefix sharing + GB10 decode optimization [WIP] Jun 26, 2026
mudler added 22 commits June 26, 2026 12:58
New backend = stock llama-cpp grpc-server + the paged patchset (forces LLAMA_PAGED=on),
shipped as its own meta-backend (mirrors turboquant, simpler: no fork pin, no
grpc-server patching - the paged runtime hooks already exist in grpc-server.cpp).
Stock llama-cpp untouched (LLAMA_PAGED?=on retained; the de-risk flip deferred for
sign-off). Gallery: qwen3.6-27b-nvfp4 (dense) + qwen3.6-35b-a3b-nvfp4 (MoE) with the
benchmark run config (paged_kv, max_batch_tokens, parallel, flash_attention, f16),
mudler/ GGUF uris (sha256 TODO until publish). Importer dropdown entry + tests.

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
…in -> 9d5d882d)

Sync to master (12 commits) + the llama.cpp pin bump 8be759e6 -> 9d5d882d.
Conflicts resolved:
- Makefile .NOTPARALLEL: union (keep both backends/llama-cpp-localai-paged and
  master's backends/privacy-filter-darwin).
- gallery/index.yaml: our 2 base NVFP4 entries (qwen3.6-27b-nvfp4, qwen3.6-35b-a3b-nvfp4)
  for the paged backend prepended to master's full list; master keeps its own
  *-nvfp4-mtp variants (distinct entries). Go build + YAML validated; the 8 duplicate
  gallery names are pre-existing in master, not introduced here.

The patchset still needs re-verification against the new tip (pin-sync, next step).

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
…ches)

The worktree merge bumped LLAMA_VERSION 8be759e6 -> 9d5d882d. This re-syncs the
paged patch-stack (0001-0024) to the new tip: the stack was rebased onto
9d5d882d on the DGX dev tree, rebuilt clean (CUDA sm_121), and re-validated
bit-exact before re-exporting the LocalAI .patch files.

Re-exporting each shipped patch from its rebased commit and diffing body-to-body
against the committed files identifies exactly 4 that changed and no longer
git-apply to 9d5d882d:

- 0008 cross-request prefix share: re-anchored the [paged 0008] commit block to
  the refactored update_slots() lambda (continue->return, batch.n_tokens->
  batch.size()); identical env-guarded logic.
- 0013 static prefill budget: budget var-block / while-gate / admission-break
  re-expressed against the refactored loop (add_ok=false idiom).
- 0015 expert-density MoE token-tile auto-select: pure context re-anchor; upstream
  inserted a test_mul_mat_id case at the hunk anchor in test-backend-ops.cpp. The
  inserted lines are unchanged. (This one rebased cleanly via 3-way but its
  committed .patch no longer applies with plain git apply, so it is caught by the
  per-patch apply-check, not by the rebase conflict count.)
- 0016 dynamic decode-first budget: dynamic budget block + n_decode_in_batch =
  batch.size() + add_ok=false against the refactored loop.

All four are byte-faithful format-patch exports of the gate-green rebased commits.
Applying the full corrected series to a fresh 9d5d882d reproduces the gate-green
tree byte-for-byte across every code file.

The other 7 touched patches (0009/0017/0018/0019/0020/0021/0024) are LINENUM-only
(hunk bodies byte-identical, only @@ line-numbers shifted) and still apply
cleanly, so they are left unchanged. The remaining patches are identical.

Validation on the rebased build (NVFP4 Qwen3.6, GB10 sm_121):
- test-backend-ops CUDA0: GATED_DELTA_NET 36/36, SSM_CONV 45/45, MUL_MAT
  1146/1146, MUL_MAT_ID 806/806 all OK.
- greedy md5 (-fa on -n 48 --temp 0 --seed 1): dense q36-27b-nvfp4
  5951a5b4d624ce891e22ab5fca9bc439 and MoE q36-35b-a3b-nvfp4
  07db32c2bcb78d17a43ed18bc22705cd, both == baseline.
- decode S_TG @npl128: dense 366.41 t/s (ref 373.2, -1.8%), MoE 751.11 t/s
  (ref 745.7, +0.7%), both within noise.

Details in backend/cpp/llama-cpp/patches/paged/PIN_SYNC_9d5d882d.md.

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
…findings

Mirror of llama.cpp dev-tree patch 0025 (qwen35moe NVFP4 MoE-decode re-graph) and the GPU-agent B
findings in SPEEDUP_HUNT.md: re-confirmed MoE decode decomposition @npl128, the measured re-graph
lever (+4.4%/+2.9%/+1.9% decode_agg at npl 32/64/128; bit-exact: test-backend-ops MUL_MAT_ID 806/806
+ parallel-greedy np16 byte-identical ON==OFF), grouped-GEMM occupancy headroom (exhausted on this
bandwidth-bound model), and the W4A16 assessment (rejected: non-bit-exact, slower BF16 MMA).

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Append lever C (structural dense residual: lm_head + scheduling) findings
and the master RANK + PLAN section to SPEEDUP_HUNT.md. Per-lever scorecard
(gain x tractability x gate), ranked build order, the concrete A build plan
for the hybrid per-head f32/bf16 SSM state cache, and the ordered B/C/D queue
with each one's build trigger.

Verdict: ship the MoE re-graph (patch 0025, measured +1.9-4.4%, both gates
PASSED) now; build A as the lead (only lever ABOVE vLLM on dense, KL-gated,
~430-454 t/s = 103-108% of vLLM); bank B-2/B-3 on MoE; C last (<1% bit-exact,
dead-end); D opt-in-only and dense-only behind the same KL gate bf16-SSM failed.

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Lever A patch + build/de-risk results. Splits the persisted gated-DeltaNet
recurrent state per head: f32 on long-memory heads (where bf16 rounding does not
contract and the KL error concentrates), bf16 on fast-decaying heads, classified
at model load by tau_h = 1/(|ssm_a|*softplus(ssm_dt)). Default ssm_hybrid_tau_thresh
= 0.0 keeps every head f32 (bit-exact opt-out).

De-risk gates BOTH PASS: test-backend-ops GATED_DELTA_NET CUDA0 OK (incl 32 hybrid
mixed CUDA-vs-CPU cases); default all-f32 greedy md5 == 0023 baseline both models
(dense 5951a5b4d624ce891e22ab5fca9bc439, MoE 07db32c2bcb78d17a43ed18bc22705cd).

Known open issue (opt-in hybrid only; default unaffected): hybrid-ON model decode
(ids in-place path) is incoherent; classifier/cache/kernel-params verified correct,
bug isolated to the ids in-place cross-step state path. See A_HYBRID_SSM_RESULTS.md.
Not ready for the GateSweep until fixed.

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Assisted-by: Claude:opus-4.8 [Claude Code]
…gate sweep (patch 0026)

Regenerate patch 0026 with the hybrid-decode carry fix and record the
KL/throughput gate-sweep results.

Fix: clear(data=true) zeroes the whole recurrent buffer including the head_slot
maps, which were uploaded only once at construction; after the post-warmup
reset every head read head_slot==0 (f32-local-0), collapsing the split and
producing incoherent decode. Persist head_slot_host and re-upload via
upload_head_slots() after every buffer clear. Hybrid decode is now coherent and
the cross-op state carry is byte-exact (write==read, both partitions).

Gate result: de-risk PASS (test-backend-ops 84/84; T=0 md5 == 0023 baseline,
both models). Ship gate FAILS - no T_thresh meets MeanKLD<1e-3 AND
same-top-p>=99.5% with a meaningful speedup. The premise that the bf16 error
concentrates in long-memory heads is refuted: KL scales with the bf16 head
count and saturates ~0.06/~91% (MoE saturates at the minimal split). The carry
is byte-exact, so this is genuine bf16 sensitivity, not a bug. The byte-saving
lever is real (dense +12.4%, MoE +11.5% decode @npl128 at T=128) but cannot
meet the strict KL bar. Shipped default-off (f32, bit-exact opt-out); hybrid is
opt-in only and not recommended in the gallery config. Full tables in
A_HYBRID_SSM_RESULTS.md.

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
…droom)

B-2 / M1 (SPEEDUP_HUNT rank #2): bit-exact block/grid/occupancy retune of
quantize_mmq_nvfp4 (the MoE down_proj activation-quant, ~2% of the MoE decode
step). Built+measured on a clean 0025 base (DGX GB10 sm_121), then reverted -
it does not lift.

Finding: the existing blockDim.x=128 is ALREADY the kernel-level optimum for
quantize_mmq_nvfp4 on GB10. nsys (8193 invocations): block=128 total 117.4M ns
is the fastest; 64 +8.7%, 192 +9.9%, 256 +6.9%. End-to-end MoE decode_agg is
flat within 0.4% noise across all block sizes {32..256} (npl32 ~438, npl128
~751 t/s). The act-quant is ~2% of a BW-bound step, so even a perfect kernel
caps the win at ~2%, and 128 is already optimal => measured 0%. Same outcome as
patch 0015 (M-tile) and 0017 (MINBLOCKS): no occupancy headroom on this
256-tiny-expert BW-bound model.

Bit-exactness proven: md5 identical at block 64/128/256 for both models (the
per-thread quant body is untouched; thread->output map is invariant to
blockDim.x). Gate at default: dense 5951a5b4 == ref, MoE 07db32c2 == ref,
MUL_MAT 1146/1146, MUL_MAT_ID 806/806 PASS.

MoE stays ~85% of vLLM @npl128 / ~87% @npl32 - still well below vLLM, so the
remaining MoE lever is B-3 (mmq_y-down warp-remap on the grouped FP4 GEMM).
No patch 0027; dev tree reverted to pristine 0025. Full data in B_MOE_RESULTS.md.

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
…ng ~85% of vLLM

B-3 (the 0017-deferred mmq_y-down warp-remap of the NVFP4 grouped FP4-MMA
mul_mat_q) was built bit-exact on the clean 0025 base and measured: the
grouped GEMM kernel itself runs -1.3% (occupancy did rise via the nwarps=4
warp-remap / 128 threads-per-CTA), but end-to-end MoE decode is FLAT
(npl128 +0.4%, npl32 +0.3%, within noise) because the stream-k fixup grows
+42% (mmq_y=64 doubles the row-tiles) and the step is SSM/BW-bound. md5 PASS
both models, test-backend-ops MUL_MAT 1146/1146 + MUL_MAT_ID 806/806 PASS.
No patch 0028; DGX dev tree reverted to pristine 0025.

Assessment: the bit-exact MoE GEMM/launch track is exhausted (B-1 re-graph
banked ~82->85%; B-2 and B-3 are 0). Honest bit-exact MoE ceiling = ~85% of
vLLM @npl128. The residual is the structural Marlin-NvFp4 grouped-GEMM gap
that no bit-exact lever closes. Recommend shipping the ~85% bit-exact default
and exposing the held 0026 bf16-SSM as a default-off opt-in (it reaches ~95%
but is non-bit-exact and fails the MoE KL gate).

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
… mode

Patch 0026 added the hybrid per-head bf16 SSM-state opt-in as the
ssm_hybrid_tau_thresh cparam + the --ssm-bf16-tau CLI flag (default 0 =
bit-exact f32). Expose it per-model via the LocalAI gallery/model YAML
`options:` list, mirroring the paged_kv / max_batch_tokens setenv hooks.

- grpc-server.cpp: new `ssm_bf16_tau` (alias `ssm_hybrid_tau`) option ->
  setenv(LLAMA_SSM_BF16_TAU) when the value parses to a positive float. It
  does NOT reference the paged-only common_params field, so the turboquant
  fork (which lacks patch 0026) stays byte-clean.
- patch 0026 (common.cpp common_context_params_to_llama): getenv fallback
  feeds cparams.ssm_hybrid_tau_thresh from LLAMA_SSM_BF16_TAU only when the
  --ssm-bf16-tau CLI flag is unset (0). Absent/non-positive env => untouched,
  so stock stays bit-exact; the CLI flag takes precedence when set.
- docs: backend/index.yaml note, docs backends.md, gallery header NOTE
  (referencing A_HYBRID_SSM_RESULTS.md; the 2 NVFP4 entries stay bit-exact).

Byte-safe when unset: with no ssm_bf16_tau option the env is never touched
and the default f32 bit-exact recurrence is preserved. Verified the parse +
consume code paths with a standalone compile-and-run (option string ->
LLAMA_SSM_BF16_TAU -> tau, plus 0 / garbage / CLI-precedence / unset cases).

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
…e Marlin GEMM

Ground-truth side-by-side per-kernel ms/step of the MoE decode gap on DGX GB10.
llama (752 t/s, step 169.8ms) vs vLLM graphs-on (901-equiv, step 142.0ms): 27.8ms gap.

Headline: the grouped MoE-expert GEMM is a llama WIN - native FP4-MMA W4A4 47.3ms
vs vLLM Marlin W4A16 50.0ms at the tiny-M decode shape. A Marlin-style W4A16 MoE
GEMM would be slower; it is not the lever (extends the w4a16-marlin DENSE verdict).

The 15% lives elsewhere: bf16 projections + convert glue (+6.5ms), recurrence
state-gather plumbing (+6.6ms, led by k_get_rows 5.2ms), graph coverage + stream
overlap (~+7ms), W4A4 act-quant tax (+3.3ms), router/glue (+5.4ms).

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
…GEMM is a llama win

Cross-agent synthesis on top of the both-engine nsys decomposition (3b59571):
settle the user's "can we do what vLLM does on MoE?" question with the three
converging investigations (groundtruth measurement + vllm-marlin source-read +
marlin-port feasibility).

Verdict: vLLM's ~15% MoE-decode lead is NOT the Marlin GEMM (that bucket is a
-1.7 ms llama WIN: native FP4-MMA W4A4 47.3 vs Marlin W4A16 50.0 at the ragged
tiny-M decode shape, both at the LPDDR5x BW floor). The gap is bf16
dense-projection bandwidth (+6.5), recurrence state-gather plumbing (+6.6, led
by k_get_rows 5.2), graph/stream-overlap overhead (~+7), W4A4 act-quant tax
(+3.3), and router/glue (+5.4).

A W4A16/Marlin grouped MoE GEMM is REJECTED (default and opt-in): it would
regress the 27% GEMM bucket to half-rate bf16 MMA, re-enter the GB10 occupancy
wall the dense scaffold already STOPPED at, and its entire intrinsic upside is
the ~2% act-quant tax - smaller than the bit-exact +1.9% the 0025 re-graph
already banked, and closeable bit-exactly by fusing the act-quant.

Recommended build (none a new MoE GEMM): (1) fuse the k_get_rows SSM-state
gather (bit-exact, ~+5, biggest single-kernel win); (2) extend CUDA-graph
coverage + stream overlap (bit-exact, ~+7); (3) fuse the W4A4 act-quant into
RMSNorm/SiLU (bit-exact, +3.3); (4) NVFP4-quantize the still-bf16 GDN/attn
projections + lm_head (bit-changing, +6.5, the same NVFP4-dense-quant move vLLM
makes). Bit-exact levers alone reach ~94% of vLLM; with the projection quant
~96-97%, parity-or-better physically in reach since both heaviest kernels
(SSM core, MoE GEMM) are already llama wins.

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Fuse the residual k_get_rows_float in the gated-DeltaNet decode path (the biggest
single kernel vLLM lacks per MOE_GAP_VS_VLLM.md, ~5.2 ms/step MoE). 0019 fused the
SSM-state gather, 0021 fused the conv compute but kept a build_rs gather for the
conv taps; nsys located that conv-state tap gather (n_embd_r=24576 floats x 128
seqs, ~720 x ~115 us per 24-step window) as the last k_get_rows in the GDN path.

New op ggml_ssm_conv_update_inplace_ids reads each sequence's prior conv taps from
cache[ids[s]] in-kernel (identity in place from the write slot, non-identity via a
disjoint scratch), mirroring the 0019 in-place + ids fusion. Bit-exact: read VALUES
unchanged, only the read path changes. Helps both dense and MoE (shared GDN conv).

GATE test-backend-ops (CUDA0 2/2): SSM_CONV_UPDATE_IDS, SSM_CONV_UPDATE, SSM_CONV,
GATED_DELTA_NET, GET_ROWS all PASS. GATE greedy md5 (-temp 0 -seed 1 -n 48)
BYTE-IDENTICAL both models: q36-27b-nvfp4 5951a5b4..., q36-35b-a3b-nvfp4 07db32c2...
nsys: k_get_rows<float,float> 10174 -> 9454 instances, 186.3 -> 102.8 ms (720 conv
gathers eliminated, replaced by a ~1.1 us no-op gather).

Built and gated on the DGX llama tree (branch paged, commit 944636c, f32 default).

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Add qwen3.6-27b-nvfp4-mtp-paged and qwen3.6-35b-a3b-nvfp4-mtp-paged: the
existing michaelw9999 NVFP4-MTP GGUFs (same uri/sha256/filename and the
recommended Qwen3.6 sampling defaults) wired to backend
llama-cpp-localai-paged with our optimized paged options (f16, flash
attention, 128k context, gpu_layers 99, batch 512, paged_kv, decode-first
max_batch_tokens, kv_unified:false, parallel:128).

These coexist with the stock llama-cpp *-nvfp4-mtp entries (distinct
-paged names) so the four LocalAI-paged NVFP4 entries sit together at the
top of the gallery.

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Rename the two base NVFP4 entries to a consistent -paged suffix
(qwen3.6-27b-nvfp4 -> qwen3.6-27b-nvfp4-paged, qwen3.6-35b-a3b-nvfp4 ->
qwen3.6-35b-a3b-nvfp4-paged) so all four base/MTP paged entries share the
naming convention. Update the two matching examples in the backend plan doc.

Add qwopus3.6-27b-v2-mtp-nvfp4-paged and qwopus3.6-27b-coder-mtp-nvfp4-paged:
verbatim copies of the stock qwopus NVFP4-MTP entries (same GGUF uri/sha256,
sampling, template, tags, function block) rewired onto the LocalAI
paged-attention stack (backend llama-cpp-localai-paged; f16, flash_attention,
131072 context, 99 gpu_layers, batch 512; paged_kv + max_batch_tokens:512 +
kv_unified:false + parallel:128). The stock entries are left untouched.

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
The dense + MoE base NVFP4 GGUFs are live (huggingface.co/mudler/Qwen3.6-27B-NVFP4-GGUF
and .../Qwen3.6-35B-A3B-NVFP4-GGUF), sha256 verified vs the Hub LFS hash, uris resolve.
Replaces the placeholder/not-yet-published TODO.

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
…-attention

# Conflicts:
#	gallery/index.yaml
…tion (patch 0028)

Anchors the rigorous same-session A/B validation of patch 0028 (residual conv-state
tap k_get_rows fusion) on this worktree branch with sign-off attribution. The
regenerated 0028 patch + bench-updated LEVER1_GATHER_RESULTS.md first landed via a
concurrent origin/master merge (c1f1d1e) that swept the staged files; this records
the provenance and the bench summary in the checkpoint.

Gate (bit-exact, greedy --temp 0 --seed 1 -n 48): dense q36-27b-nvfp4
5951a5b4d624ce891e22ab5fca9bc439, MoE q36-35b-a3b-nvfp4 07db32c2bcb78d17a43ed18bc22705cd
(both == baseline; base == lever1). decode_agg npl128: dense 369.95 -> 377.83 t/s
(+2.13%, 96.6% of vLLM), MoE 763.47 -> 777.95 t/s (+1.90%, 86.3% of vLLM). nsys MoE
decode: k_get_rows_float 17334 -> 15414 inst (-1920), 358.37 -> 133.52 ms, step -3.13 ms.

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
…tions (+6.5ms bucket)

Scopes lever 4 (read-only, no GPU) on top of the flat levers 2+3. Root cause: the
MoE GGUF (nvidia modelopt, 241 NVFP4 tensors) quantized only the experts and left the
GDN/attn linear projections in BF16, while the dense GGUF (unsloth, 304 NVFP4 tensors)
already has them NVFP4 (proven: dense ssm_out runs FP4 MMQ; dense decode at 96.6% of
vLLM). Lever 4 = re-quantize the MoE GGUF's bf16 GDN/attn projections to NVFP4, the same
move vLLM makes on the identical weights - the +6.5ms projections bucket, the largest
single banked MoE gain available.

Path: offline re-quantize to a new GGUF variant (expanded --tensor-type); zero kernel
code - the loader sidecar-scale path + tuned mul_mat_q<NVFP4> are already in tree and
proven by the dense GGUF. Bit-changing => KL-gate, not md5. KL expected to pass (per-step
non-accumulating weight quant, unlike the failed bf16-state; experts already W4A4-clean);
lm_head is the one risky tensor (gate on argmax-agreement). Expected ~+4-6.5ms => MoE
86.3% -> ~88-91% of vLLM. Recommend a separate OPT-IN gallery variant (preserve the
bit-exact default; promote to default only if the KL gate is clean).

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
…L, no-ship

Re-quantizing the MoE GGUF's bf16 GDN/attn projections to NVFP4 (the lever-4
scope hypothesis) fails the KL gate on every axis vs the shipping NVFP4 baseline:
PPL +6.51% (FULL) / +6.15% (CONS) against a <1% gate, mean KLD-to-f16 0.164/0.172
vs baseline 0.137, top-1 argmax agreement down ~2.2-2.6 points. Both projq
variants rejected; in_proj_ba being kept bf16 (CONS) recovered almost nothing, so
the damage is in the bulk attn/GDN projections.

Root cause: the bf16 projections are a deliberate modelopt precision choice, not a
provenance accident. vLLM runs the same modelopt checkpoint, so it keeps these
projections bf16 too - the baseline GGUF already matches vLLM. The ~20.3ms
projection-GEMM bucket is the price of high-precision projections that vLLM also
pays; it is not the llama-vs-vLLM lever it appeared to be. The speed win is only
purchasable with a 6% PPL regression. MoE stays at 86.3% of vLLM @ npl128.

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Conclude the MoE-parity hunt. The two remaining sub-levers in the
20.3-vs-13.8 ms projection bucket are both bit-changing or at the BW floor:

- convert-glue (3.24 ms/step, measured: 1.73 input f32->bf16 + 1.52 output
  bf16->f32): NOT bit-exact eliminable. ggml-cuda.cu:1663-1690 rounds the f32
  GEMM accumulator to bf16 (CUDA_R_16BF dst) then widens to f32; that
  bf16-rounded value is load-bearing for the shipped md5. Removing the
  round-trip (f32-direct output, bf16 residual stream, or NVFP4 weights) all
  rebaseline md5. A precision boundary, like lever 4.
- bf16 projection GEMM (17.27 ms/step): BW-bound at the LPDDR5x floor
  (~4.7 GB/step at 273 GB/s; M=128 -> 128 FLOP/byte vs >900 ridge). nvjet
  already TMA-streams the weights; cutlass reads the same bytes. No kernel
  lever; only fewer bytes (quantize) helps - rejected on quality.

Corrects the body premise that vLLM runs these projections as NVFP4-Marlin:
vLLM runs the same nvidia-modelopt checkpoint that keeps them BF16, so the
projection bucket is a matched-precision gap, not a quant gap.

Realistic bit-exact MoE ceiling ~86-88% of vLLM; shipped lever 1 (86.3%) is
at it. No one-more-lever for MoE. Only clean win left is DENSE (+0.41% lever 5),
gated behind resolving the paged-MoE baseline md5 drift.

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Mirror of paged-dev commit e2acb3b (lever 5). get_block_table() is recomputed
once per full-attention layer per decode step, but the KV cell layout is fixed
for the whole step (it only changes in apply()). This caches the table the first
time it is built in a step and memcpy-reuses the identical bytes for the rest,
invalidating in apply(). Bit-exact; toggle off with LLAMA_PAGED_NO_BT_CACHE=1.

Host-side get_block_table time (llama-batched-bench, npp128 ntg128 npl128,
cache OFF -> ON): MoE 112.94 -> 14.82 ms (-87%), dense 193.78 -> 16.90 ms (-91%).
Dense decode is partly host-bound and gains (TG 364.8 -> 374.7 t/s, ~96% of the
vLLM 391 t/s @npl128 reference); MoE decode is compute-bound (FP4 GEMM) so the
saved host time is off the critical path and MoE TG is flat. Details in
LEVER5_HOSTPIPE_RESULTS.md.

Also records the per-path bit-exactness gate (PAGED_BITEXACT_NOTE.md): the
paged-MoE greedy md5 (8cb0ce23) differs from the non-paged md5 (07db32c2) by a
benign FP-accumulation-order difference of the paged attention reduction, not a
bug. KL-validated vs the f16 reference (16 chunks, c512): KLD(paged||f16) =
0.13600 <= KLD(nonpaged||f16) = 0.13660, PPL(paged) = 7.4009 ~ PPL(nonpaged) =
7.3896 (within +/- 0.29). Canonical references are now per path: non-paged MoE
07db32c2 and paged MoE 8cb0ce23; dense is bit-exact across paths (5951a5b4).

Assisted-by: Claude:opus-4.8 [Claude Code]
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Labels

None yet

Projects

None yet

Development

Successfully merging this pull request may close these issues.

3 participants