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[Bugfix] DeepSeek V4 reasoning parser: don't split DSML tool-call marker across streaming deltas#17

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[Bugfix] DeepSeek V4 reasoning parser: don't split DSML tool-call marker across streaming deltas#17
tobymao wants to merge 87 commits into
jasl:codex/ds4-sm120-min-enablefrom
tobymao:fix/dsv4-reasoning-tool-marker-split

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@tobymao tobymao commented Jun 6, 2026

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Purpose

In thinking mode, DeepSeekV4ThinkingReasoningParser treats the DSML tool-call start marker <|DSML|tool_calls> as an implicit end-of-reasoning when the model omits </think> (common at long context). The detection uses text.find(marker), which only matches the complete marker. When the marker arrives split across streaming deltas (e.g. <|DSML|tool then _calls>), the partial prefix is emitted as reasoning and only _calls> reaches content — so the tool-call parser never sees the start token. The tool call leaks as text and the agent loop ends with nothing to dispatch, indistinguishable client-side from "the model gave up".

Relates to vllm-project#41132 and vllm-project#40801 (DSML fragments leaking under tool_choice=auto + streaming / thinking).

Fix

Hold back any trailing bytes of current_text that form a partial prefix of an implicit-end marker (via the existing partial_tag_overlap helper) until a later delta resolves them. On marker completion, hand the whole marker — reconstructed from current_text, so a straddled marker stays intact — to content. The bookkeeping is delta-relative (len(previous_text) - held_len), so it makes no assumption about whether earlier reasoning flowed through this method and preserves the existing within-delta behavior.

Test

Added test_implicit_end_marker_split_across_deltas to tests/reasoning/test_deepseekv4_reasoning_parser.py: the partial prefix is held back (not leaked into reasoning), and the completed marker reaches content whole so the tool parser sees its start token.

Test Result

pytest tests/reasoning/test_deepseekv4_reasoning_parser.py18 passed (17 existing + 1 new). Also verified end-to-end on 2x DGX Spark (sm120): an agent run that previously ended at the first split marker now completes tool calls and passes its task.

jasl and others added 30 commits June 6, 2026 19:10
Protect hybrid-aligned DeepSeek V4 MLA prompt cache blocks so they survive decode and unrelated cache churn. Release those protected references under admission pressure and before prefix-cache reset so they do not starve the block pool.

Add regression coverage for reuse after decode pressure, admission under protected refs, and reset cleanup.

Signed-off-by: jasl <jasl9187@hotmail.com>
Signed-off-by: jasl <jasl9187@hotmail.com>
Signed-off-by: jasl <jasl9187@hotmail.com>
Signed-off-by: jasl <jasl9187@hotmail.com>
Signed-off-by: jasl <jasl9187@hotmail.com>
Signed-off-by: jasl <jasl9187@hotmail.com>
Fix the SM12x fp8 einsum custom-op registration import, skip unused DeepSeek V4 MTP checkpoint tensors before safetensors materialization, and release MXFP4 setup temporaries after kernel setup.

Signed-off-by: jasl <jasl9187@hotmail.com>
Forward model skip_weight_name_before_load filters into the fastsafetensors iterator and skip filtered keys before materializing tensors. This keeps DeepSeek V4 non-MTP loads from reading MTP-only weights when users select --load-format fastsafetensors.

Keep the regression coverage at behavior level by checking the DefaultModelLoader path and pruning private implementation-field assertions from the adjacent DeepSeek V4 prefix-cache tests.

Co-authored-by: OpenAI Codex <codex@openai.com>
Signed-off-by: jasl <jasl9187@hotmail.com>
Import the production-preview warmups for DeepSeek V4 request preparation, sparse MLA attention, and mHC TileLang kernels while leaving the old warmup test fixture out of the preview branch.

Cherry-picked-from: 0dca30b

Cherry-picked-from: 5959aad

Cherry-picked-from: 7cf6f1d
Signed-off-by: jasl <jasl9187@hotmail.com>
Signed-off-by: jasl <jasl9187@hotmail.com>
Signed-off-by: jasl <jasl9187@hotmail.com>
Signed-off-by: jasl <jasl9187@hotmail.com>
Replaces the placeholder configs added in commit 7b0f8b9 ("Add Blackwell
tuning config aliases") with real autotuning results from benchmark_w8a8_
block_fp8.py on the actual hardware.

Coverage:
- M-keys extended from [1, 4, 8, 16, 32] to
  [1, 2, 4, 8, 16, 32, 64, 128, 256, 512] — adds short prefill (M=64..128)
  and long prefill (M=256, 512) anchors that decode dispatch was previously
  rounding down to "M=32" placeholder.
- 6 (N, K) shapes × 4 device variants (RTX PRO 6000 Workstation/Server/
  Max-Q Edition + GB10) = 24 JSON files.
- Hardware-specific: Workstation Edition tuned on physical RTX PRO 6000
  Blackwell Workstation Edition; Server Edition and Max-Q Workstation
  Edition share the SM120 architecture and identical 24G/96G memory
  configs, only TGP differs, so they reuse the Workstation Edition
  tunings. GB10 (SM121) tuned separately on physical hardware.

Search space:
- Base: vllm's get_configs_compute_bound() — 1280 (BLOCK_M, BLOCK_N,
  BLOCK_K, GROUP_SIZE_M, num_warps, num_stages) combinations.
- Per-M filter: BLOCK_SIZE_M >= max(16, M/8) (cap 64) for M>=64 — drops
  configs guaranteed to be catastrophic at large M (cdiv(M, BLOCK_M) > 8
  iterations sentence the kernel to many M-loops on cold cache).
- num_iters: 10 for M<=32, 7 for M=64..128, 5 for M>=256.

Why the placeholders mattered:
- Placeholder had BLOCK_M=16 for every M (since all 5 keys were copies of
  the same config). At M=256 the kernel did cdiv(256, 16) = 16 iterations
  along M; at M=512, 32 iterations.
- Observed behavior: long-prefill at M=256 took 7+ minutes per request,
  M=512 didn't return within 40 minutes. Tuned configs pick BLOCK_M=64..
  128 for these M values (2-4 M-iterations), unblocking long prefill.

Tuning wall clock:
- Workstation Edition: 57.7 min on RTX PRO 6000 Blackwell Workstation
  Edition (single GPU).
- GB10: 66.2 min on NVIDIA GB10 (single GPU).
- Shape 1 + Shape 3 (cold compiles for K=4096 and K=1024) dominated; the
  other 4 shapes each took <2 min via Triton JIT cache reuse (M/N/K are
  runtime args, so (BLOCK_M, BLOCK_N, BLOCK_K, num_warps, num_stages)
  cache hits across (N, K) once the K-divisibility class is compiled).

Same hardware verifies: tests/quantization/test_sm12x_tuned_config_lookup.py
still passes (asserts shape coverage, not contents).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Signed-off-by: jasl <jasl9187@hotmail.com>
The single-stream decode profile showed `_fp8_paged_mqa_logits_kernel`
at 12.61% of decode kernel time, 84.87 µs/call — jasl#3 single hotspot
on SM120 TP=2 after T1-A. Investigation: the launch used hardcoded
`BLOCK_M=4` regardless of `num_rows = batch_size * next_n`. For the
common no-MTP single-stream decode case, num_rows=1, which means 75%
of the M-axis work (3 of 4 rows) is masked off and discarded — pure
waste of compute and memory bandwidth.

Fix: pick the smallest power-of-2 tile that still covers num_rows.
- num_rows == 1 (no-MTP decode, batch=1): BLOCK_M=1
- num_rows == 2: BLOCK_M=2
- num_rows in [3, 4] (MTP=2 batch=1, or batch=4 prefill chunks): BLOCK_M=4
- num_rows > 4: BLOCK_M=8

Cost: each unique block_m value compiles a separate Triton
specialization, so cudagraph capture exercises four variants instead
of one. Triton JIT cache amortises this — first warmup adds a few
seconds, subsequent loads cache-hit.

Expected impact:
- Single-stream decode (num_rows=1): 84.87 µs/call → ~25-30 µs/call
  (eliminate 3 of 4 wasted rows). At 42 calls/tok that's ~2.3 ms/tok
  TPOT improvement, ~8% throughput uplift on no-MTP single-stream.
- MTP=2 (num_rows=3 typical): BLOCK_M=4 unchanged (1 row masked, same
  as before). No regression.
- Prefill (num_rows >= 4): BLOCK_M=4 or 8 picked — covers full work.

Risk: low. Kernel logic unchanged; only the launch tile size adapts.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Signed-off-by: jasl <jasl9187@hotmail.com>
The candidate_block path in finish_materialized_sparse_mla_scores_with_sink
took the caller-supplied value_block_size as BLOCK_D directly. DSv4 calls
it with value_block_size=512 (matmul_sparse_mla_attention_with_sink default
for use_dot_finish=True) but the actual head_dim from combined_kv is
qk_nope+qk_rope = 128+64 = 192. With BLOCK_D=512, the kernel masks off
positions 192..511 per program — 62.5% of D-axis work discarded.

Fix: clamp block_d to the smallest power-of-2 >= head_dim from the allowed
set {64, 128, 256, 512}. For DSv4 head_dim=192 this picks BLOCK_D=256
(25% mask waste instead of 62.5%). Caller-supplied value_block_size
smaller than the target (intentional fine-grained D-axis splits) is still
respected.

Expected impact on SM12x decode profile: _finish_materialized_scores_with
_sink_candidate_block_kernel time per call drops from 17.92 µs to roughly
half (less work per program, same grid size). At 82 calls/token that's
~0.7 ms/tok TPOT savings → ~2-3% throughput uplift on top of T1-D.

Risk: low. Kernel logic unchanged; only the per-launch BLOCK_D adapts to
the actual head_dim, falling back to 512 for head_dim > 512.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Signed-off-by: jasl <jasl9187@hotmail.com>
The prefill warmup constant was 1024 tokens. With `max_num_batched_tokens
= 8192` (the canonical SM12x serve setting), the first real request that
prefills more than 1024 tokens in a single chunk has to JIT-compile the
dense FP8 W8A8 block-scaled GEMM at the larger M, plus the sparse-MLA
prefill kernel against a longer KV slab. T1-A's autotuned config space
makes the cold-compile cost bigger, not smaller, so any user who issues
an 8K-context first request after a fresh serve currently waits on
Triton compilation that the warmup hook is supposed to absorb.

Lift the constant to 8192. The call site already clamps via
`_clamp_warmup_tokens(requested, scheduler_config.max_num_batched_tokens)`
so schedulers running with a smaller batched-token cap naturally warm at
their cap, and configurations that lift the cap above 8192 keep this
floor (the cost of warming beyond 8192 grows fast enough that we want a
deliberate decision rather than implicit scaling).

Measured on 2x RTX PRO 6000 Workstation Edition (SM120, TP=2 EP,
max_num_batched_tokens=8192) with a cold random ISL=8192 OSL=512
num-prompts=4 c=1 bench against a freshly-restarted serve:

  Before: TTFT mean ≈ 17 s (cold first request dominates the average)
  After:  TTFT mean 3,172 ms, TTFT p99 3,176 ms (mean ≈ p99 — the
          cold-start variance disappears)
  Throughput: 61.16 tok/s vs 54.20 tok/s on the 020e0c8 baseline
              for the same shape (+13 %)
  Startup time: 71 s -> 80 s (+9 s one-time)

Signed-off-by: jasl <jasl9187@hotmail.com>
Three follow-on fixes on top of `5c8975591`:

1. Drop the hardcoded `_DEEPSEEK_V4_MTP_UNIFORM_DECODE_WARMUP_REQUESTS
   = (1, 2)` ceiling and append `scheduler_config.max_num_seqs` so MTP
   uniform-decode warmup also covers the largest in-flight batch the
   server will ever issue. On a Spark MTP=2 cluster with
   max_num_seqs=4 this lifts the random ISL=8,192 OSL=512 c=4 cold
   throughput from 23.67 tok/s to 42.82 tok/s (+81 %) by warming the
   `_fp8_paged_mqa_logits_kernel` adaptive `BLOCK_M=8` path that the
   (1, 2) tier missed.

2. Add a chunked-prefill warmup `_dummy_run` that sets
   `profile_seq_lens = prefill_tokens * 2` so the indexer / sparse-MLA
   builders see "this is the second chunk of a longer sequence", not
   only the freshly-arriving single chunk.

3. Add a multi-request prefill warmup `_dummy_run` (no `create_*`
   flags) so the runner splits the batched-token budget across
   `max_num_seqs` requests and exercises the multi-prefill indexer
   path that single-request prefill warmup skips.

Cost: ~+35 s startup on Spark (init engine: 61.33 s -> 96.81 s) for a
one-time JIT pass over the larger shape coverage.

Limitation: vLLM's `jit_monitor` shows nine kernels still JIT during
the first c=1 cold bench, including `eagle_prepare_next_token_padded_kernel`
and `_w8a8_triton_block_scaled_mm` at alt shapes. These kernels are
already invoked from `_run_deepseek_v4_mtp_spec_decode_warmup_kernels`,
but the synthesized warmup tensors hit a different Triton specialization
key (notably pointer 16-byte alignment) than the sampler / spec-decode
buffers used in real inference. Closing this gap requires routing
warmup through the actual scheduler / sampler pipeline rather than a
dummy_run helper, which is a larger upstream change. The harness
(`scripts/prewarm_serve.sh`, also auto-invoked by
`scripts/dgx_spark_start_mp_serve.sh`) issues real-pipeline prewarm
requests after `/health=200` to absorb the remaining cold-start cost
on the deployment side.

Signed-off-by: jasl <jasl9187@hotmail.com>
The earlier `ds4-sm120-full` PoC branch shipped two FP8 paged-MQA
logits kernels — a generic 2D-tiled one and a per-row variant
(`_fp8_paged_mqa_logits_rowwise_kernel`) tuned for long decode
contexts. During the file split that produced
`vllm/v1/attention/ops/deepseek_v4_ops/sm12x_mqa.py`, only the
2D-tiled kernel was carried over; the rowwise variant and its
dispatcher gate were dropped.

Users running ctx > 100K with MTP=2 on RTX PRO 6000 (Max-Q) report
~20% throughput regression vs the PoC branch on the
"Red-Black Tree, max_tokens=2048, thinking on" 5-run probe
(~85 tok/s here vs ~108 tok/s on `da4f1c711`). Single-stream short
contexts are unaffected because the 2D-tile work scales with
`token_count` cdiv 64 and the rowwise win comes from Q-reuse across
the full 4K-128K window per program — exactly the regime the bug
report hits.

This commit restores the rowwise kernel verbatim from `da4f1c711`
(its routing predicate is aligned with `4c9ee613d`, dropping the
`next_n == 1` constraint so MTP=2 also hits the rowwise path), and
re-introduces the dispatch in `fp8_paged_mqa_logits_triton`:

    if head_dim % 64 == 0 and num_heads % 4 == 0:
        return fp8_paged_mqa_logits_rowwise_triton(...)

DSv4-Flash (head_dim=128, num_heads=64) always satisfies both
predicates so all real serves take the rowwise path; the 2D-tiled
kernel remains as the fallback for misaligned shapes and is still
the canonical reference the rowwise kernel was validated against in
the original PoC tests.

The recently-added T1-D adaptive `BLOCK_M` (commit `959a04df5`) is
preserved in the 2D-tiled path. On DSv4-Flash it becomes dead code
in practice, but kept for portability and to keep the diff isolated
from the long-context regression fix.

Signed-off-by: jasl <jasl9187@hotmail.com>
…aming

Adds a DSv4-specific reasoning parser
(`DeepSeekV4ThinkingReasoningParser`, `DeepSeekV4ReasoningParser`) that
treats the DSML tool-call start marker `<|DSML|tool_calls>` as an
implicit end-of-reasoning when the explicit `</think>` token is absent.

Why
---
DSv4-Flash at long context (~95k-100k input tokens) occasionally fails
to emit `</think>` before opening a tool call. The existing
`DeepSeekR1ReasoningParser` keeps the parser stuck in reasoning mode in
that case: the tool-call start marker (and everything after) is
classified as reasoning, the orchestrator never advances to the tool
parser, and the caller sees a turn with reasoning but no tool call.
opencode's agent loop interprets that as "no tool to dispatch" and
exits — visually indistinguishable from "the model gave up".

Reproduced 18% of the time at 95-100k input tokens with `tool_choice`
auto and 25 tools in scope. Full repro bundle (Python script + SSE
trace + opencode forensics) lives in the harness repo.

What
----
- New module `vllm/reasoning/deepseek_v4_reasoning_parser.py` providing
  `DeepSeekV4ThinkingReasoningParser` (extends
  `DeepSeekR1ReasoningParser` with one defensive split), plus the
  dispatcher pair `DeepSeekV4ReasoningParser` and
  `DeepSeekV4ReasoningWithThinkingParser` matching the V3 shape.
- The dispatcher mirrors `DeepSeekV3ReasoningParser`: thinking-mode
  uses the V4 extension, non-thinking uses `IdentityReasoningParser`.
- Sticky `_implicit_end_seen` flag on the parser instance ensures
  `is_reasoning_end[_streaming]` returns True for every delta after the
  marker first appears, so the orchestrator state machine transitions
  correctly even when the marker spans a token boundary.
- `vllm/reasoning/__init__.py` re-points the `deepseek_v4` registration
  from `DeepSeekV3ReasoningParser` to the new
  `DeepSeekV4ReasoningParser`. `deepseek_v3` is unchanged.

What does NOT change
--------------------
- Healthy streams (explicit `</think>`) take the same code path as
  before: the V4 parser defers to `super()` and the defensive split
  only fires when no explicit start/end token has been seen.
- The DSv32 tool parser is untouched.
- V3 reasoning parser and registration are untouched.

Tests
-----
- `tests/reasoning/test_deepseekv4_reasoning_parser.py` covers the
  registration, dispatcher selection, healthy paths (parent
  behaviour), implicit-end-marker in isolated delta, implicit-end split
  within delta, sticky behaviour after first marker, suppression when
  `<think>` is explicitly present, `is_reasoning_end` for explicit and
  implicit cases, and the parent's single-token guard.
- `tests/reasoning/test_deepseekv3_reasoning_parser.py` updated: the
  `deepseek_v4` alias now resolves to `DeepSeekV4ReasoningParser`,
  while `deepseek_v3` still resolves to `DeepSeekV3ReasoningParser`.

The fix is intentionally narrow: it addresses one well-defined failure
mode (tool call without closing reasoning). The "runaway reasoning to
length limit with no tool call" and "premature reasoning stop with no
tool call" subtypes seen at long context are model-behaviour issues,
not parser bugs, and are left for a separate follow-up.

Signed-off-by: jasl <jasl9187@hotmail.com>
…pper

Replaces the previous attempt to put the decorator directly on
``HCHeadOp.forward_cuda``: when the outer model is wrapped by
``@support_torch_compile`` (the no-MTP path on SM12x) dynamo can't
inline-bind the decorated method through ``CustomOp._forward_method``
and the worker dies with::

    torch._dynamo.exc.Unsupported: failed to bind arguments when
    attempting to inline forward_cuda

That blocks every no-MTP serve on SM12x. Move the body into a free
``_hc_head_cuda_impl`` decorated with
``@torch.compile(backend=simple_compile_backend)`` — the layout that
existed pre-upstream-vllm-project#41946 — so the method just delegates and dynamo
no longer needs to inline a decorated method. Recovers the DSv4-Flash
MTP=2 spec-acceptance gain reported in 16ee3bd (67.6 % → 59.8 % drop)
without breaking the no-MTP startup path.

``forward_hip`` is unchanged: ROCm doesn't take the same outer
``@support_torch_compile`` route, so the method-level decorator is
fine there.

Signed-off-by: jasl <jasl9187@hotmail.com>
The third ``_dummy_run`` call added in f4b3301 ("Extend DeepSeek V4
warmup coverage to multi-request shapes") synthesizes a multi-request
prefill batch and runs it through ``force_attention=True``. On SM12x
this trips an illegal memory access inside the CUTeDSL
``DequantGatherKCacheKernel``: the dummy shape exceeds the
``offset + gather_len <= M`` invariant of the kv-gather output buffer
(M is sized for the single-prefill warmup case, not for the
multi-request layout).

Reproduced with ``CUDA_LAUNCH_BLOCKING=1``::

    File ".../dequant_gather_k_cutedsl.py", line 29, in
      dequantize_and_gather_k_cache_cutedsl
    DequantGatherKCacheKernel.compile(...)(
        out, k_cache, seq_lens, gather_lens, block_table, offset)
    RuntimeError: CUDA Error: cudaErrorIllegalAddress

Drop just this third warmup call. The other two (single-prefill and
second-chunk-of-chunked-prefill) and the MTP uniform-decode coverage
from f4b3301 stay. The trade is a one-time JIT compile on the first
real multi-prefill user request for the un-pre-warmed indexer path;
the alternative is failing to start the serve at production
``--max-num-seqs`` values (e.g. 128).

A proper fix would reconcile the gather-buffer sizing for the
multi-request prefill warmup with the kernel's bounds; left for a
follow-up.

Signed-off-by: jasl <jasl9187@hotmail.com>
``FlashMLASparseMetadataBuilder.get_cudagraph_support`` and the
parallel override in ``DeepseekSparseSWAMetadataBuilder`` were guarded
on::

    getattr(kv_cache_spec, "model_version", None) == "deepseek_v4"
    and is_triton_sparse_mla_enabled_for_platform()

The first clause never holds at runtime: the spec the runtime passes to
``get_cudagraph_support`` is an outer
``UniformTypeKVCacheSpecs`` wrapper (``vllm/v1/kv_cache_interface.py``)
that only exposes ``block_size``; the per-layer
``MLAAttentionSpec.model_version`` lives one level down under
``.kv_cache_specs``. So the overrides silently fall through to
``cls._cudagraph_support = AttentionCGSupport.UNIFORM_BATCH`` and
cudagraphs are captured normally — confirmed by instrumenting the call
and by an ``--enforce-eager`` probe (FULL cudagraphs give a ~2.4×
decode throughput speedup on 2× RTX PRO 6000 at ISL=2048 OSL=2048
c=16).

Cudagraph capture is also fine for the MTP=2 path on this stack — the
spec-decode acceptance and TPOT match the no-MTP measurement to within
mt-bench noise (66.10 % acceptance, length 2.32).

Since the override was both dead code and would *reduce* performance
if "fixed" to actually fire, drop it. The default ``UNIFORM_BATCH``
support level on both builders already does the right thing.

Signed-off-by: jasl <jasl9187@hotmail.com>
Defensive ``.contiguous()`` on ``decode_metadata.seq_lens[:batch_size]``.
On an already-contiguous slice this is a no-op pointer return; on a
non-contiguous 2D slice (max_decode_len < next_n under V2 model
runner cudagraph capture) it materializes a contiguous copy that
satisfies ``persistent_topk`` and the FP8 MQA paged-logits kernels.

Reported by @aabbccddwasd in PR vllm-project#41834 (comment 4450901180) as a
crash workaround on their 4× RTX PRO 6000 TP=4 setup; cost is zero
on the path we currently exercise (already contiguous).

Signed-off-by: jasl <jasl9187@hotmail.com>
``_deepseek_v4_sm12x_fp8_einsum_kernel`` was launched with hardcoded
``num_warps=4 num_stages=3``; ``_fused_indexer_q_rope_quant_kernel``
was launched with ``num_warps=1`` (with a "TODO: Tune this"
inline). Replace both with ``@triton.autotune`` so the best
warp/stage config is picked per shape:

- fp8_einsum: configs over ``{(4,3), (8,3), (4,2), (8,2)}`` keyed on
  ``(num_tokens, num_groups, out_rank, hidden_size)``.
- fused_indexer_q: configs over ``num_warps={1,2,4}`` keyed on
  ``(INDEX_Q_HALF_ROT_DIM, INDEX_Q_HEAD_DIM)``.

Both kernels are launched per forward, so autotune fires once per
unique key and the cached selection is reused on subsequent calls.

Reported by @aabbccddwasd in PR vllm-project#41834 (comment 4450901180).

Signed-off-by: jasl <jasl9187@hotmail.com>
Add ``@triton.autotune({(num_warps, num_stages) in {4,8} × {2,3}})``
to the three single-head prefill accumulate kernels in
``sparse_mla_kernels.py``::

- ``_accumulate_indexed_attention_chunk_kernel``
- ``_accumulate_fp8ds_global_slots_attention_chunk_kernel``
- ``_accumulate_fp8ds_paged_attention_chunk_kernel``

Each was previously launched with hardcoded ``num_warps=8``; the new
configs explore ``{4,8}`` × ``{2,3}`` keyed on ``num_candidates``
(the dominant per-shape factor). Autotune fires once per
``num_candidates`` value seen at runtime and the chosen config is
cached for subsequent calls.

The two multihead variants (``..._multihead_kernel``) are NOT
autotuned in this commit: they share the same accumulate-read-write
pattern but per @aabbccddwasd's note (PR vllm-project#41834 comment 4450901180)
need a separate ``num_tokens: tl.constexpr`` + ``reset_to_zero``
treatment for autotune correctness, which we'll add in a follow-up
once we've validated the single-head gain on this hardware.

Reported by @aabbccddwasd in PR vllm-project#41834 (comment 4450901180);
claimed ~+39 % prefill on 4× RTX PRO 6000 TP=4 32K ctx, with the PR
base already having a higher baseline so absolute gain is smaller.

Signed-off-by: jasl <jasl9187@hotmail.com>
Tuned via ``scripts/_fp8_block_tune_driver.py`` for the three remaining
DSv4-Flash dense linear shapes the workstation hits at TP=2 but didn't
yet have ship-tuned configs for:

- N=4096, K=2048  (q_b / gate projection)
- N=1024, K=4096  (wq_b projection)
- N=4096, K=512   (wo_b projection)

Suggested by @aabbccddwasd in PR vllm-project#41834 (comment 4450901180). Tuned
on the local 2× RTX PRO 6000 Blackwell Workstation Edition host with
the same wrapper that produced the existing six configs in this
directory; lookup is device-name keyed so no code changes required.

These complement the existing six WS-edition configs (N,K) ∈
{(1536, 4096), (2048, 4096), (4096, 1024), (4096, 4096), (8192, 1024),
(16384, 1024)} so DSv4-Flash now hits a tuned config for every dense
linear shape it issues, instead of falling back to the default
heuristic for the three shapes above.

Signed-off-by: jasl <jasl9187@hotmail.com>
…nges)

Cudagraph-safe retry of suggestion jasl#2 from PR vllm-project#41834 comment 4450901180.
Previous attempt (e34daef, reverted) also exposed
``c128a_*_effective_topk`` on the metadata and truncated the buffer
slice inside ``deepseek_v4_attention``; that truncation baked the
shape into the captured forward launch, breaking replay when
``effective_topk`` shifted between capture and replay.

This version only touches the metadata builder (which already runs
*outside* the captured forward), so per-call ``effective_topk``
variation is fine:

1. Pre-fill ``global_decode_buffer[:num_decode_tokens]`` and
   ``prefill_buffer[:num_prefill_tokens]`` with ``-1`` before launch.
2. Compute ``effective_topk_arg = cdiv(max num_compressed across
   in-flight tokens, BLOCK_SIZE) * BLOCK_SIZE``, capped at
   ``max_compressed_tokens``.
3. Kernel inner loop uses ``effective_topk`` (was
   ``max_compressed_tokens``); store mask uses the same.

The buffer entries the kernel skips
(``[effective_topk, max_compressed_tokens)``) stay at ``-1`` from the
pre-fill, so downstream sparse MLA accumulate kernels (which still
iterate the full ``max_compressed_tokens`` width inside the cudagraph)
see only ``-1`` sentinels in the tail and short-circuit them via
``kv_index >= 0`` / ``candidate < valid_len`` checks. No tensor shape
changes inside the captured forward → cudagraph capture/replay
remains correct.

Savings here are limited to the metadata kernel itself; the accumulate
kernels' iteration count is unchanged (their loop bound is the captured
``num_candidates`` shape value, which we deliberately do not narrow).
Bench at long ``max_model_len`` will confirm whether this is enough to
recover a meaningful chunk of the ~27 % TPOT regression observed at
``max_model_len=131072`` vs ``8192``.

Signed-off-by: jasl <jasl9187@hotmail.com>
…date loop

Redesigned suggestion jasl#3 from PR vllm-project#41834 comment 4450901180. The first
attempt (e34daef, reverted; later 72a5ff2, also reverted) tried to
truncate ``topk_indices.shape[1]`` in Python so the captured launches
iterated a narrower combined slice; that approach broke under cudagraph
replay (shape baked at capture) and *also* mis-bounded — the combine
kernel writes each token's combined buffer as ``[topk_len_t |
swa_len_t | -1 padding]`` with SWA *immediately* following the
per-token topk, so a fixed ``effective_topk`` cap cuts off the SWA
portion (GSM8K dropped 25 pp on the prior attempt).

The kernel already loads the per-token combined length
(``valid_len = tl.load(lens_ptr + token_idx)`` for the four ``lens``-
gated kernels, ``gather_len`` for the two paged kernels). The existing
``is_valid`` guard only short-circuits the *heavy* work past that
length; the outer ``for candidate_idx in range(0, num_candidates)``
still pays one ``tl.load`` + branch per iter on the dead tail.
Capping the loop at
``min(num_candidates, valid_len - candidate_offset)`` (clamped to 0)
removes those wasted iterations while preserving the existing
``is_valid`` semantics: the iterations we now skip are exactly those
the existing guard already discarded.

Applied to six accumulate kernels in ``sparse_mla_kernels.py``:

- ``_accumulate_gathered_attention_chunk_kernel``
- ``_accumulate_indexed_attention_chunk_kernel``                 [autotuned in jasl#1]
- ``_accumulate_fp8ds_global_slots_attention_chunk_kernel``      [autotuned in jasl#1]
- ``_accumulate_fp8ds_global_slots_attention_chunk_multihead_kernel``  [decode]
- ``_accumulate_fp8ds_paged_attention_chunk_kernel``             [autotuned in jasl#1]
- ``_accumulate_fp8ds_paged_attention_chunk_multihead_kernel``   [decode]

CUDA-graph safety: ``lens_ptr`` / ``gather_lens_ptr`` are stable
addresses; their values are refreshed per call by the metadata builder
(outside the captured forward) and by ``combine_topk_swa_indices``
(inside the forward but writing only into the persistent buffers the
accumulate kernels read from). The kernel inner-loop bound is a
runtime-loaded scalar — Triton compiles a dynamic loop and the captured
launch picks up the current value on each replay.

Savings scale with ``combined_topk_buffer_width - actual valid length``
(i.e. mostly visible at long ``max_model_len`` with shorter actual
contexts). At our test shape (``max_model_len=131072``, ISL=2048) the
saved iterations come mostly from the decode multihead path; expected
to be neutral / no-regression at short ``max_model_len`` where the
bound equals ``num_candidates``.

Signed-off-by: jasl <jasl9187@hotmail.com>
Three pure comment/docstring fixes from the audit, no behavior change:

1. ``_build_c128a_topk_metadata_kernel`` comment was ambiguous about
   ``max_compressed_tokens`` after the parameter was renamed to
   ``effective_topk`` in 304944e. Reword to explicitly point at the
   Python caller (``build_c128a_topk_metadata``) and explain that
   ``max_compressed_tokens`` is the buffer column width and entries
   past ``effective_topk`` stay at ``-1`` via the caller's ``fill_(-1)``
   pre-pass.
2. Add an inline note next to ``positions.max().item()`` flagging it as
   a host sync that is safe here because the builder runs outside the
   captured forward.
3. Expand ``MLAAttentionManager`` class docstring: the predicate
   ``_should_protect_prompt_blocks`` triggers on three independent
   conditions (DSv4 model_version, fp8_ds_mla cache_dtype_str, or
   compress_ratio > 1), not just DSv4. Document the three conditions
   inline so a future tightening pass does not accidentally narrow the
   coverage.

Signed-off-by: jasl <jasl9187@hotmail.com>
…kip_weight_name

Two refactors from the audit, no behavior change:

1. ``vllm/v1/attention/ops/deepseek_v4_ops/fp8_einsum.py`` had its own
   copy of ``_upcast_e8m0_to_fp32`` (4 lines, identical to the canonical
   helper at ``vllm/model_executor/layers/quantization/utils/fp8_utils.
   py:1017``). Other peer call sites (cutlass.py, rocm_aiter_mla_sparse.
   py, mxfp4.py) already import from ``fp8_utils``; do the same here.

2. ``DeepseekV4ForCausalLM.skip_weight_name_before_load`` used
   ``hf_to_vllm_mapper.apply_list([name])`` to map a single name. That
   builds a one-element list and routes through a list-comprehension
   that filters ``None``. Use the canonical 1-to-1 helper
   ``WeightsMapper._map_name`` directly, matching the pattern used in
   ``compressed_tensors.py``, ``adapters.py``, ``bitsandbytes_loader.
   py``, and ``lora/utils.py``. Same semantics, 3 lines instead of 5.

Signed-off-by: jasl <jasl9187@hotmail.com>
jasl and others added 17 commits June 6, 2026 19:10
Signed-off-by: jasl <jasl9187@hotmail.com>
Signed-off-by: jasl <jasl9187@hotmail.com>
Signed-off-by: jasl <jasl9187@hotmail.com>
Signed-off-by: jasl <jasl9187@hotmail.com>
Signed-off-by: jasl <jasl9187@hotmail.com>
Co-authored-by: OpenAI Codex <codex@openai.com>
Signed-off-by: jasl <jasl9187@hotmail.com>
Signed-off-by: jasl <jasl9187@hotmail.com>
Signed-off-by: jasl <jasl9187@hotmail.com>
Signed-off-by: jasl <jasl9187@hotmail.com>
Signed-off-by: jasl <jasl9187@hotmail.com>
Signed-off-by: jasl <jasl9187@hotmail.com>
Signed-off-by: jasl <jasl9187@hotmail.com>
Signed-off-by: jasl <jasl9187@hotmail.com>
Signed-off-by: jasl <jasl9187@hotmail.com>
Signed-off-by: jasl <jasl9187@hotmail.com>
Signed-off-by: jasl <jasl9187@hotmail.com>
…ker across streaming deltas

In thinking mode the V4 reasoning parser treats the DSML tool-call start
marker (<|DSML|tool_calls>) as an implicit end-of-reasoning when the model
omits </think>. Detection used text.find(marker), which only matches the
complete marker; when the marker arrives split across streaming deltas
("<|DSML|tool" then "_calls>"), the partial prefix is emitted as reasoning
and only "_calls>" reaches content, so the tool parser never sees the start
token. The tool call leaks as text and the agent loop ends with nothing to
dispatch. Relates to vllm-project#41132 and vllm-project#40801.

Hold back trailing bytes of current_text that form a partial prefix of an
implicit-end marker (via partial_tag_overlap) until a later delta resolves
them; on completion hand the whole marker (taken from current_text, so a
straddled marker stays intact) to content. Bookkeeping is delta-relative
(len(previous_text) - held_len), preserving the existing within-delta path.

Signed-off-by: tobymao <toby.mao@gmail.com>
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@jasl jasl force-pushed the codex/ds4-sm120-min-enable branch 5 times, most recently from f32247a to 71cbb6b Compare June 13, 2026 12:32
@jasl

jasl commented Jun 14, 2026

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Oh, sorry, I missed the PR.
I'll test it and cherry-pick commits (with your credit) today, thank you!

@jasl jasl force-pushed the codex/ds4-sm120-min-enable branch 3 times, most recently from 531807c to f031e42 Compare June 14, 2026 14:39
@jasl

jasl commented Jun 14, 2026

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Oh, the issue may have been resolved in the latest commit, could you give a retry?

@tobymao

tobymao commented Jun 14, 2026

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yes, you're right i think it's fixed, i'll close this out. thank you for your hard work

@tobymao tobymao closed this Jun 14, 2026
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3 participants