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[common] Grouped gemm update - nvfp4 for blackwell and fp8 blockwise hopper#2971

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[common] Grouped gemm update - nvfp4 for blackwell and fp8 blockwise hopper#2971
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pggPL:grouped_gemm_nvfp4_and_hopper

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@pggPL pggPL commented May 8, 2026

Description

Adds Hopper (SM90) support to cuBLAS grouped GEMM and enables NVFP4 / FP8 block scaling recipes.

Fixes #2455

Type of change

  • Documentation change
  • Bug fix (non-breaking change which fixes an issue)
  • New feature (non-breaking change which adds functionality)
  • Breaking change
  • Infra/Build change
  • Code refactoring

Checklist

  • I have read and followed the contributing guidelines
  • The functionality is complete
  • I have commented my code, particularly in hard-to-understand areas
  • I have made corresponding changes to the documentation
  • My changes generate no new warnings
  • I have added tests that prove my fix is effective or that my feature works
  • New and existing unit tests pass locally with my changes

pggPL and others added 13 commits March 16, 2026 11:36
Signed-off-by: Pawel Gadzinski <pgadzinski@nvidia.com>
Signed-off-by: Pawel Gadzinski <pgadzinski@nvidia.com>
Signed-off-by: Pawel Gadzinski <pgadzinski@nvidia.com>
Use existing nvte_set_grouped_tensor_param with kNVTEGroupedWithGEMMSwizzledScales
instead of the dedicated set/get functions.

Signed-off-by: Pawel Gadzinski <pgadzinski@nvidia.com>
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
- Add CUBLAS_NVFP4_GROUPED_GEMM_VERSION and CUBLAS_FP8_BLOCK_GROUPED_GEMM_VERSION macros (13.4+)
- Update check_grouped_gemm_requirements to allow SM90 with cuBLAS 13.4+
- Refactor execute_grouped_gemm to use GroupedGemmConfig struct
- Add divisibility-by-128 validation for FP8 block scaling in setup kernel and quantizer
- Support scalar alpha/beta for Hopper (no per-group alpha/beta)
- Expose get_grouped_gemm_setup_workspace_size to PyTorch via pybind
- Update PyTorch tests to run grouped GEMM on Hopper with cuBLAS 13.4+

Signed-off-by: Pawel Gadzinski <pgadzinski@nvidia.com>
Made-with: Cursor
… scaling tests on Hopper

Extend nvte_grouped_gemm_with_discrete_inputA to handle NVFP4 (Float4E2M1)
inputs: accept kFloat4E2M1 dtype, propagate scale_inv pointers, collect
contiguous amax from discrete tensors, and enforce swizzled-scales checks
for NVFP4 alongside MXFP8. Also add GTEST_SKIP for FP8 tensor scaling
grouped GEMM on Hopper since cuBLAS does not support it there.

Signed-off-by: Pawel Gadzinski <pgadzinski@nvidia.com>
Made-with: Cursor
…M tests

The setup kernel computes per-tensor scale pointers as data_offset /
block_size, which assumes no padding in the scale buffer. This is only
correct when first_dim % 128 == 0 and last_dim % 128 == 0 (MXFP8) or
last_dim % 64 == 0 (NVFP4). Add explicit assertions in
build_grouped_tensor to catch any future test shapes that violate this.

Signed-off-by: Pawel Gadzinski <pgadzinski@nvidia.com>
Made-with: Cursor
…d_hopper

Conflicts resolved (3 files):

* tests/pytorch/test_numerics.py
  test_grouped_gemm_grouped_tensor: combined skip rules — Hopper (SM90) requires
  cuBLAS 13.4+, Blackwell+ (SM100) requires cuBLAS 13.3+. Kept main's
  use_bias_scale parametrization.

* transformer_engine/pytorch/cpp_extensions/gemm.py
  general_grouped_gemm_for_grouped_tensor: combined HEAD's num_alphabeta logic
  (single scalar on Hopper, per-group on Blackwell+) with main's cached
  _get_fp32_ones_tensor / _get_fp32_zeros_tensor helpers.

* transformer_engine/common/gemm/cublaslt_grouped_gemm.cu
  - validate_grouped_gemm_inputs: kept HEAD's NVFP4 / FP8 block-scaling
    consistency checks, wrapped in main's nullptr-guard / continue-on-no-data
    pattern.
  - GroupedGemmConfig struct retained; added sm_count from main and
    propagated config_.sm_count -> gemm_config.sm_count in all three
    public APIs.
  - kMaxTensorsPerKernel rename to kMaxGroups (= 64) adopted from main.
  - execute_grouped_gemm signature uses GroupedGemmConfig (HEAD); body uses
    config.sm_count for CUBLASLT_MATMUL_DESC_SM_COUNT_TARGET (from main).
  - Dropped HEAD's simple grouped_bias_add_kernel (dead code); kept main's
    advanced grouped_bias_add_kernel + find_tensor_for_row helper.
  - Replaced inline SM/cuBLAS preambles with check_grouped_gemm_requirements()
    calls in nvte_grouped_gemm, nvte_grouped_gemm_with_discrete_inputA, and
    nvte_grouped_gemm_with_discrete_out. The helper supports both
    Hopper (SM90 + cuBLAS 13.4+) and Blackwell+ (SM100 + cuBLAS 13.3+).
  - Kept HEAD's validate_grouped_gemm_inputs(..., use_per_group_alpha_beta)
    signature for proper alpha/beta validation across architectures.

Signed-off-by: Pawel Gadzinski <pgadzinski@nvidia.com>
Made-with: Cursor
…or swizzle tests

cublaslt_grouped_gemm.cu:
- Fix incorrect handling of NVFP4/MXFP8 columnwise data in
  build_grouped_gemm_multi_inputA_args by adding a swap_dims flag
  consistent with choose_grouped_operand_storage. Use A_sel.trans
  (post-flip) for gemm_config.avg_k so K is selected from the
  correct dim with discrete A_list.

tests/cpp/test_common.{h,cu}:
- Add enforce_grouped_gemm_alignment parameter (default true) to
  build_grouped_tensor; the MXFP8/NVFP4 first/last_dim 128/64
  alignment asserts are only relevant for the grouped GEMM setup
  kernel, so callers that bypass it (swizzle/unswizzle) opt out.

tests/cpp/operator/test_swizzle.cu:
- Pass enforce_grouped_gemm_alignment=false to build_grouped_tensor
  in MXFP8 swizzle/unswizzle/roundtrip tests, which intentionally
  exercise non-padded shapes.

tests/cpp/operator/test_grouped_gemm.cu:
- Sync GPU/cuBLAS skip rules across all 3 sub-tests, add
  cudaDeviceSynchronize() after nvte_multi_tensor_gemm reference for
  defensive sync, and skip NVFP4 + AllDifferent in all 3 sub-tests
  due to a known flaky bug in the nvte_multi_tensor_gemm reference.

Signed-off-by: Pawel Gadzinski <pgadzinski@nvidia.com>
Made-with: Cursor
Signed-off-by: Pawel Gadzinski <pgadzinski@nvidia.com>
Made-with: Cursor
…and_hopper

Signed-off-by: Pawel Gadzinski <pgadzinski@nvidia.com>
Co-authored-by: Cursor <cursoragent@cursor.com>

# Conflicts:
#	transformer_engine/common/gemm/cublaslt_grouped_gemm.cu
@pggPL pggPL force-pushed the grouped_gemm_nvfp4_and_hopper branch 2 times, most recently from 335627f to 3f523e7 Compare May 11, 2026 14:04
pggPL and others added 4 commits May 11, 2026 16:13
Apply the same fix as upstream PR NVIDIA#2954 (MXFP8 unaligned dims) to the
analogous NVFP4 / FP8 block scaling paths in setup_grouped_gemm_kernel.

Background: cuBLAS grouped GEMM expects each expert's scale_inv to live
at a specific offset in the contiguous grouped buffer. The quantizer
allocates each per-expert scale_inv tensor padded to the layout cuBLAS
needs (swizzled 128x4 for MX/NV; ceildiv(., 128) x roundup(., 4) for
block scaling). The setup kernel was computing these offsets as
data_offset / block_size for everything except MXFP8 — silently correct
when dims align to 128, but pointing at the middle of the previous
expert's scale tile when they do not. In MoE forward this is reachable
through variable per-expert token counts.

Add three device helpers mirroring compute_grouped_tensor_mxfp8_-
scale_inv_offset:
- compute_grouped_tensor_nvfp4_scale_inv_offset
- compute_grouped_tensor_block_1d_scale_inv_offset
- compute_grouped_tensor_block_2d_scale_inv_offset
Each sums the same padded per-tensor sizes the quantizer uses at alloc
time (Float8BlockQuantizer::get_scale_shape, NVFP4Quantizer::get_scale_-
shape).

NVFP4 columnwise data is set up via use_columnwise(swap_dims=true), so
sel.shape is already pre-transposed for that recipe — the rowwise
formula on (first, last) recovers the colwise alloc. For block scaling
the formula depends on the canonical orientation, so propagate a new
swap_dims field on GroupedOperandSelection and pass effective_rowwise
(sel.rowwise || sel.swap_dims) into the kernel. MXFP8 is invariant
under this change because swap_dims is always false there and its
helper's byte count is invariant under the rowwise flag anyway.

Test: add ShapeCase::kUnalignedAllSame with (M, N, K) = (160, 288, 416)
— all multiples of 32/16 (per-recipe block size) but none multiples of
128, so each expert's scale tile is padded. Exercise it across MXFP8 /
NVFP4 / FP8 block scaling and the three transpose configs that match
the existing parameter grid. Relax build_grouped_tensor's defensive
%128 / %64 alignment assertions to %32 / %16 (block-size only), which
is the actual quantizer requirement now that the offset arithmetic no
longer assumes zero padding.

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Signed-off-by: Pawel Gadzinski <pgadzinski@nvidia.com>
…st cleanup

Production:
- nvte_grouped_gemm_with_discrete_inputA no longer requires per-expert amax
  buffers to be contiguous. Add `amax_ptrs[kMaxGroups]` to MultiTensorGroupGemmInputArgs
  and read each tensor's amax via indirection in setup_grouped_gemm_kernel
  (mirrors the existing scale_inv_ptrs pattern). The launcher enables the
  NVFP4 alpha computation when amax is available from either source.
- Consolidate four near-identical
  compute_grouped_tensor_{mxfp8,nvfp4,block_1d,block_2d}_scale_inv_offset
  into a single template `compute_grouped_scale_inv_offset<PaddedFn>` and
  collapse the A/B recipe-switch in setup_grouped_gemm_kernel into a local
  `fill_scale_ptr` lambda.

Tests:
- Drop the per-test amax staging workaround in run_grouped_gemm_discrete_in_case
  (no longer needed after the contiguity relax).
- Fix amax management in make_nvfp4_operand: copy values into result's own
  amax buffers instead of aliasing pointers (prevents double-free).
- Extract the three duplicated cuBLAS-version/compute-capability skip blocks
  into a shared `grouped_gemm_skip_reason` helper.

Signed-off-by: Pawel Gadzinski <pgadzinski@nvidia.com>
Co-authored-by: Cursor <cursoragent@cursor.com>
Silences -Wunused-variable (NVIDIA#177-D in nvcc).

Signed-off-by: Pawel Gadzinski <pgadzinski@nvidia.com>
Co-authored-by: Cursor <cursoragent@cursor.com>
@pggPL pggPL force-pushed the grouped_gemm_nvfp4_and_hopper branch from fcefde1 to ce0e4d2 Compare May 11, 2026 14:14
pggPL added 2 commits May 11, 2026 16:17
Signed-off-by: Pawel Gadzinski <pgadzinski@nvidia.com>
Signed-off-by: Pawel Gadzinski <pgadzinski@nvidia.com>
@pggPL pggPL force-pushed the grouped_gemm_nvfp4_and_hopper branch from ce0e4d2 to a4df7bd Compare May 11, 2026 14:20
pggPL and others added 2 commits May 11, 2026 16:44
- nvte_grouped_gemm and nvte_grouped_gemm_with_discrete_out now validate
  per-operand amax for NVFP4 (previously silently dropped the global-scale
  factor when amax was missing). discrete_inputA path also checks B's amax.
- Remove unused ShapeCase::kUnalignedAllSameNVFP4 enum and its comment.
- OperandStorageChoice::swap_dims now defaults to false; rowwise returns
  no longer pass spurious swap_dims=true.
- Unify GroupedGemmSetupWorkspace layout: from_buffers(nullptr, n) returns
  the total byte count, and required_setup_size derives its result from it
  so the layout cannot drift between the two.
- test_common.cu: consolidate the three gather_*_scales lambdas into a
  single gather_scale_inv(bytes_per_elem, get_shape, get_cpu_ptr) helper.
- test_grouped_gemm.cu: extract make_grouped_gemm_ref / make_alpha_beta /
  compare_grouped_d_to_multi helpers; the three run_* variants drop from
  ~1029 to 774 lines with no behavior change.

Signed-off-by: Pawel Gadzinski <pgadzinski@nvidia.com>
Co-authored-by: Cursor <cursoragent@cursor.com>
@pggPL pggPL marked this pull request as ready for review May 11, 2026 15:20
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pggPL commented May 11, 2026

/te-ci pytorch

@pggPL pggPL requested a review from vthumbe1503 May 11, 2026 15:23
Comment thread transformer_engine/common/gemm/cublaslt_grouped_gemm.cu
pggPL and others added 4 commits May 15, 2026 18:36
Two related bugs in the grouped GEMM path were causing FP8 block scaling
NT and NN cases to fail on Hopper for non-Mul128 dims (Mul32 tests).

1. build_grouped_gemm_multi_inputA_args (discrete-A path) used
   t->shape() (LOGICAL) for cuBLAS rows/cols, while the symmetric
   grouped path (build_grouped_tensor / select_grouped_operand) uses
   tensors[i]->{rowwise,columnwise}_shape() (PHYSICAL). For FP8 block
   columnwise the two differ (physical is transposed of logical), so
   args.rows became N instead of K. Switch the discrete-A path to use
   data.shape directly — this aligns both paths and makes swap_dims
   redundant for this function.

2. padded_block_{1d,2d}_scale_inv_floats had a columnwise branch that
   swapped first/last in the formula, but the quantizer
   (test_common.cu:get_scales) always uses logical dims regardless of
   direction. Combined with grouped meta passing transposed dims for
   columnwise data, the formula produced wrong per-expert scale stride
   — only visible for dims not divisible by 128. The unified formula
   ceil(last/128) * roundup(first, 4) is correct for both directions
   because the meta swap and quantizer swap cancel out.

Also remove now-redundant check_fp4_output_compat duplication and trim
stale comments.

Signed-off-by: Pawel Gadzinski <pgadzinski@nvidia.com>
Signed-off-by: Pawel Gadzinski <pgadzinski@nvidia.com>
Comment thread transformer_engine/common/gemm/cublaslt_grouped_gemm.cu Outdated
pggPL and others added 4 commits May 15, 2026 21:02
Handle per-operand FP8 block scaling modes when computing grouped scale offsets, and tighten NVFP4 validation to reject unsupported mixed or non-per-group-alpha paths.

Signed-off-by: Pawel Gadzinski <pgadzinski@nvidia.com>
Avoid test cases that require direct columnwise 2D block quantization, which is not a supported test setup path.

Signed-off-by: Pawel Gadzinski <pgadzinski@nvidia.com>
Comment thread transformer_engine/common/gemm/cublaslt_grouped_gemm.cu
vthumbe1503 and others added 3 commits May 19, 2026 22:04
Added validation for FP8 block scaling support in grouped GEMM.

Signed-off-by: vthumbe1503 <vthumbe@nvidia.com>
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/te-ci

Comment thread transformer_engine/common/gemm/cublaslt_grouped_gemm.cu Outdated
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/te-ci

Comment thread transformer_engine/common/gemm/cublaslt_grouped_gemm.cu Outdated
vthumbe1503 and others added 2 commits May 20, 2026 19:36
Co-authored-by: greptile-apps[bot] <165735046+greptile-apps[bot]@users.noreply.github.com>
Signed-off-by: vthumbe1503 <vthumbe@nvidia.com>
pggPL added 3 commits May 25, 2026 14:03
- Clarify scale_inv padding comments in test_grouped_gemm.cu so it is
  obvious that kAllSameMul32 exercises per-expert scale_inv offsets only
  for recipes that pad grouped scale_inv storage.
- Centralize the 32 MiB cuBLAS workspace size into a single
  kCublasWorkspaceBytes constant in test_grouped_gemm.cu.
- Drop the test-only enforce_grouped_gemm_alignment flag from
  build_grouped_tensor and remove all its call-site overrides; alignment
  is already validated inside the grouped GEMM implementation.
- Add a short comment in cublaslt_grouped_gemm.cu explaining why the int
  and float arrays in GroupedGemmSetupWorkspace do not require an
  explicit align_ptr() call (cuBLAS only mandates 16-byte alignment for
  the pointer arrays; 4-byte natural alignment is sufficient for the
  int/float arrays and is preserved by the layout).

Signed-off-by: Pawel Gadzinski <pgadzinski@nvidia.com>
- test_swizzle.cu: drop the enforce_grouped_gemm_alignment=false argument
  introduced upstream after the flag was removed from build_grouped_tensor.
- cublaslt_grouped_gemm.cu (_with_discrete_inputA): remove redundant B
  swizzled-scales check; the same condition is already enforced inside
  validate_grouped_gemm_inputs({inputB}, ...) called just above.
- build_grouped_gemm_multi_inputA_args: drop the requires_scale_inv
  parameter and derive it per-tensor from t->dtype() / t->scaling_mode.
  validate_grouped_gemm_multi_inputA_list already enforces uniform
  scaling mode, so per-iteration evaluation is safe and removes the
  duplicated computation at the call site.

Signed-off-by: Pawel Gadzinski <pgadzinski@nvidia.com>
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pggPL commented May 25, 2026

/te-ci

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GroupedGemm: NVFP4 via cuBLAS

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