Port/aakbarza/flydsl blockmoe fusion#3810
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Pull request overview
Ports FlyDSL’s FP8/FP8 + per-1x128 FP32 blockscale 2-stage MoE GEMM into aiter, wiring it into the MoE dispatcher as an additional backend and adding functional/perf tests plus related plumbing (split-K, activations, scale handling).
Changes:
- Add vendored FlyDSL blockscale MoE stage1/stage2 kernel implementation plus adapter/dispatcher integration (including split-K and SiLU/GeLU).
- Extend FlyDSL MoE kernel registry/argument plumbing to support FP8 blockscale configs and raw-pointer (
fx.Pointer) launch ABI. - Add end-to-end FlyDSL blockscale MoE tests and update existing FlyDSL test(s); add an env var to disable FlyDSL HGEMM.
Reviewed changes
Copilot reviewed 7 out of 8 changed files in this pull request and generated 4 comments.
Show a summary per file
| File | Description |
|---|---|
| op_tests/flydsl_tests/test_silu_and_mul_fq.py | Updates test to pass raw-pointer adaptors for kernels that take fx.Pointer args. |
| op_tests/flydsl_tests/test_flydsl_blockscale_moe.py | New end-to-end correctness + split-K scaffolding + gated perf test for FP8 blockscale MoE path. |
| aiter/tuned_gemm.py | Adds AITER_DISABLE_FLYDSL_HGEMM env var gate for FlyDSL HGEMM selection. |
| aiter/ops/flydsl/moe_kernels.py | Adds FP8 blockscale kernel catalog + pointer/memref adaptor split; updates stage1/2 wrappers and args packing. |
| aiter/ops/flydsl/kernels/silu_and_mul_fq.py | Adds explicit FP8 saturation clamp prior to conversion to avoid NaN propagation. |
| aiter/ops/flydsl/kernels/blockscale_moe_gemm_2stage.py | New vendored upstream FlyDSL FP8 blockscale 2-stage MoE kernel with aiter-specific split-K and epilogue additions. |
| aiter/fused_moe.py | Adjusts per-1x128 quant scale transposition logic to include FlyDSL stage1 wrapper routing. |
| aiter/aot/flydsl/moe.py | Updates AOT precompile plumbing for new stage1 out_scale arg slot, but currently has ABI mismatches (see comments). |
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| from aiter.ops.flydsl.moe_kernels import ( | ||
| _get_compiled_silu_fused, | ||
| _ptr_view_safe, | ||
| _as_memref, | ||
| _run_compiled, |
| _as_memref(tmp_out.view(-1, inter_dim * 2)), | ||
| _as_memref(out.view(-1).view(torch.uint8)), | ||
| _as_memref(out_scale_sorted_flat), | ||
| _as_memref(sorted_token_ids), | ||
| _as_memref(num_valid_ids), | ||
| _as_memref(sorted_token_ids.view(-1)), | ||
| _as_memref(torch.empty(0, device=dev, dtype=torch.float32)), |
| _k_in, | ||
| _grid_y, | ||
| stream=0, | ||
| out_scale_sorted=_s1_scale_arg, | ||
| ) |
| blocks, | ||
| stream=None, | ||
| use_ptr=False, | ||
| ): |
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| _SUFFIX_RE = re.compile(r"(?P<fp4>_fp4)?(?P<fp8>_fp8)?(?:_sbm(?P<sbm>\d+))?$") | ||
| _SUFFIX_RE = re.compile( | ||
| r"(?P<blk>_blkscale)?(?P<fp4>_fp4)?(?P<fp8>_fp8)?(?:_sbm(?P<sbm>\d+))?$" |
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Preserve the blockscale suffix when parsing fp8 variants
When a fused-quant blockscale name uses the default variant, e.g. flydsl_moe1_afp8_wfp8_bf16_t..._blkscale_fp8, this regex consumes the whole _blkscale_fp8 tail. get_flydsl_kernel_params() then looks up the base name without _blkscale, but the blockscale registry keys are registered with _blkscale, so the lookup returns None and _flydsl_stage1_wrapper rejects an otherwise valid fp8-output blockscale kernel name. The parser should strip only the quant/sbm suffix while keeping _blkscale as part of the registered base name.
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| a_dtype=a_dtype, | ||
| b_dtype=b_dtype, | ||
| out_dtype=out_dtype, | ||
| act=act, |
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Forward Gelu activations to the blockscale kernel
For Gelu MoE configs that select this new fp8/fp8 FlyDSL blockscale path, the high-level wrapper still maps every non-Swiglu activation to act='silu' before reaching this call, even though the blockscale compiler accepts act='gelu'. That means an ActivationType.Gelu model configured with these FlyDSL kernel names will compile/run the SiLU gate instead and return numerically wrong outputs; preserve Gelu when deriving the act argument before forwarding it here.
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Verbatim snapshot of ROCm/FlyDSL kernels/moe_blockscale_2stage.py (PRs ROCm#164 / ROCm#252 / ROCm#306). Only change: rewrite two `from kernels.X` imports to relative `.X` for the aiter package layout. All referenced helpers already exist in aiter's mfma_preshuffle_pipeline.py and mfma_epilogues.py. Co-Authored-By: Claude Opus 4 <noreply@anthropic.com>
Replaces the prior 439-line TODO scaffold with a thin adapter that forwards the wide aiter dispatcher signature (25 kwargs) to the upstream entry points. Tier-A passthrough (out_dtype, scale_block_k, waves_per_eu, accumulate); Tier-B no-op accept of DSR1 defaults (silu, no bias, no pad, no swiglu_limit); Tier-C raises a clear NotImplementedError for gelu / bias / pads / split-K / persistent / xcd_swizzle / b_nt. Dispatcher (moe_kernels.py) keeps the same a_dtype='fp8',b_dtype='fp8' routing line and registers the canonical FlyDSL kernel-name set for the FP8 blockscale path so AOT precompile and tuner CSVs can resolve them. DSR1 (M=8192) via the dispatcher: FlyDSL 2219us vs CK 2533us (1.14x). Co-Authored-By: Claude Opus 4 <noreply@anthropic.com>
Adds one tuned row (M=8192,N=4096,K=7168, top_k=8, exp=256) so the AOT precompile harness in aot/flydsl/moe.py can discover the kernel. Co-Authored-By: Claude Opus 4 <noreply@anthropic.com>
12 adapter tests (signature, validation, Tier-A/B/C error paths), stage1+stage2 functional smoke at small shapes, and a gated DSR1-scale perf test that benchmarks the dispatcher path vs CK 2-stage and the ASM fused fallback. Local run on MI355: 12/12 adapter tests pass, DSR1 perf gate passes (FlyDSL 2219us vs CK 2533us, 1.14x). Co-Authored-By: Claude Opus 4 <noreply@anthropic.com>
The prior fixture quantized activations twice (per-token then per-block) which left the kernel and the FP32 reference with mismatched scales. Small-shape outputs were Inf/NaN in both paths; isclose(Inf,Inf) masked the failure as err_ratio=0.0001, and stage2 was downgraded to informational. Switch _prepare_data to a single per_group_quant_hip pass: x_bq + the [nblk_k,tokens] and [tokens,nblk_k] scale layouts the kernel and ref each need. Replace the informational-only assertions with strict tolerances (stage1 err_ratio <= 0.02, stage2 <= 0.05, no non-finite). Local on MI355: tiny (64t/dim=1024/idim=256/E=8/topk=2): s1 err=0.000, s2 err=0.000 small (256t/dim=2048/idim=512/E=16/topk=4): s1 err=0.000, s2 err=0.000 DSR1 perf gate unchanged: FlyDSL 2235.9us vs CK 2539.3us (1.14x). Co-Authored-By: Claude Opus 4 <noreply@anthropic.com>
The cshuffle epilog was gated to f16 output only by a hard raise in compile_moe_blockscale_gemm1. Route the LDS frag type and the per-element trunc through out_mlir() so bf16 can take the same fast store path that f16 already uses, and forward frag_elem_type to mfma_epilog. Required for DSR1 (bf16 out) to actually exercise the cshuffle path; the prior code would have raised ValueError as soon as the adapter forwarded out_dtype="bf16" with cshuffle enabled (the default). Adds test_dispatcher_routes_fp8_fp8_bf16_compiles to lock in the new path; every other test in the file uses out_dtype='f16' and would not have caught a regression in the bf16 store. Co-Authored-By: Claude Opus 4 <noreply@anthropic.com>
Plumb act through compile_moe_blockscale_gemm1 and select silu vs gelu
at compile time in the stage1 epilogue. GeLU uses the exact erf formula
(0.5*x*(1+erf(x/sqrt(2)))) for CK parity, implemented inline via the
Abramowitz & Stegun 7.1.26 polynomial (rocdl.exp2 + rocdl.rcp fast
path + math.absf/copysign).
Adapter Tier-C check relaxed to accept act in {silu, gelu}. Default is
unchanged (silu), so existing callers see no behavior change.
Test ref _torch_stage1_ref takes act and uses F.gelu(approximate='none')
to match the kernel; the e2e correctness test now runs both activations
at tiny/small shapes within the same tolerances.
Co-Authored-By: Claude Opus 4 <noreply@anthropic.com>
Standalone bench for the FP8/FP8 + per-1x128 FP32 blockscale MoE path,
modeled on op_tests/op_benchmarks/hip/ conventions. Reuses the launch
helpers from the test file (imported via importlib since flydsl_tests
has no __init__.py) so timing matches the gated pytest within ~2%.
Defaults to the DSR1 shape (M sweep over [1, 8, 64, 256, 1024, 4096,
8192]) but exposes presets for dsr1-tp4/tp1, mixtral-8x7b/22b,
qwen3-235b, and gpt-oss-120b. Optional --compare ck,asm columns reuse
ck_moe_stage{1,2}_fwd and aiter.fmoe_fp8_blockscale_g1u1; --compare ""
runs FlyDSL-only. CSV output to logs/flydsl_moe_blockscale_<act>.csv
for offline pivoting.
For non-DSR1 presets, the bench logs (does not assert) when the
adapter raises NotImplementedError so --preset all never aborts
halfway, and notes in the header that only DSR1 has a tuned CSV row
today.
Co-Authored-By: Claude Opus 4 <noreply@anthropic.com>
Run black==26.3.0 and ruff==0.15.7 over the new blockscale adapter, test, and benchmark files to satisfy AITER's pre-commit hooks (CONTRIBUTE.md). Co-Authored-By: Claude Opus 4 <noreply@anthropic.com>
Parallelize the K-reduction across k_batch workgroups so the M*N CTA grid
no longer under-fills the GPU at low M (DSR1 decode). When k_batch > 1
the kernel expands its z-grid, each CTA processes K/k_batch of the K
dimension, and the epilogue atomic-adds unactivated gate/up partials
into a zeroed tmp_out buffer (interleave gui_layout); the existing
silu_and_mul kernel fuses activation + reduction after the GEMM.
Adapter lifts the Tier-C k_batch != 1 gate and validates the K-slice is
divisible by scale_block_k=128, by tile_k, and that total tiles per
split is even >= 2 (the K-loop unrolls in pairs of tile_k tiles).
Upstream kernel:
- launcher grid (gx, gy, k_batch); kernel reads bz, k_offset_base
- K main-loop and tail bounds shifted by k_offset_base; scale-tensor
base inherits the shift via existing k_base/scale_block_k math
- out_rsrc byte count doubled (2*inter_dim) for split-K tmp_out
- CShuffle epilogue forced off for split-K
- new _atomic_add_scalar_via_pk helper uses raw_ptr_buffer_atomic_fadd
on a half2/bf16x2 pack (AMD has no scalar fp16/bf16 atomic) lowering
to buffer_atomic_pk_add_f16/bf16 on gfx950
- doweight_stage1 + k_batch > 1 raises NotImplementedError until the
dispatcher forwards sorted_weights to silu_and_mul_fq
Tests:
- test_splitk_valid_config_compiles[1,2,4]: compile-path guards
- test_splitk_invalid_kslice_raises: validator coverage
- test_blockscale_splitk_stage1_e2e: M in {8,64,256}, k_batch in {2,4},
err_ratio = 0.0000 vs FP32 ref
Measured speedup at DSR1 decode shape (M=8, dim=7168, inter=256):
k_batch=1: 52.0us k_batch=2: 37.6us (1.38x) k_batch=4: 23.3us (2.23x)
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Adds pick_k_batch_for_blockscale_stage1() heuristic and wires it through
flydsl_moe_stage1 via k_batch="auto". The selector estimates grid
occupancy from (M*topk, 2*inter_dim) tiles and picks k_batch to
multiply the CTA count when the base grid is too small to saturate
the GPU. Decode-1 (blocks_m == 1) is special-cased to k_batch=4 to
match measured DSR1 TP=8 optima (1.5-1.65x vs CK at M=1).
Selector is k-slice-aware: validates model_dim % k_batch, scale_block_k
and tile_k divisibility, and falls back to the next-smallest valid
k_batch (down to 1) if the desired choice is invalid for the shape.
Tests pin the measured-best k_batch for 12 DSR1 TP=8 stage1 shapes
(M in {1,8,16,32,64,128,256,1024,8192} x inter_dim in {256,512}) plus
a fall-back case for an invalid-kslice shape.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
…ow blockscale
Phase B's per-32 e8m0 sorted-tile scale layout matched silu_and_mul_fq but
NOT the fp8/fp8 stage2 GEMM, which expects a2_scale as f32 per-row
[n_blocks_k, tokens*topk] (the format per_group_quant_hip(transpose_scale=True)
produces). End-to-end piping fused_stage1 → flydsl_moe_stage2 produced
inf/nan because stage2 reinterpreted e8m0 bytes as f32 exponents.
Switch the fused fp8 epilog to emit the per-row f32 format directly, making
the fused chain a drop-in replacement for the unfused
(bf16 → per_group_quant_hip → stage2) chain.
Kernel (_blockscale_moe_gemm_2stage_upstream.py):
* Restricted to tile_n=128 (one per-128 block per CTA in N).
* Allocate tile_m × 4-wave × f32 LDS scratch for cross-wave amax.
* Two-pass epilog: (1) per-wave intra-wave shuffle_xor amax + LDS publish
by lane_mod_16==0; (2) barrier; all threads read 4 slots → per-128 amax;
quant_scale = 240/amax, clamp ±240, cvt_pk_fp8 → token-major fp8 bytes;
designated lane (wave_mod_4==0, lane_mod_16==0) writes f32 amax/240 to
per-row scale buffer at by * tokens*topk + t*topk + s.
* Drop sorted-tile address math + e8m0 headroom=8 bias (now amax/240, CK
pattern matching per_group_quant_hip).
Wrapper (blockscale_moe_gemm_2stage.py):
* Validate tile_n==128 and inter_dim%128==0 when out_dtype='fp8'.
Dispatcher (moe_kernels.py):
* For fused-fp8 GEMM path, allocate f32 buffer sized n_blocks_k * tokens*topk
(no padding) and return shape (n_blocks_k, tokens*topk). Legacy uint8
sorted-tile path (gui_sk / splitk_fp4 post-quant kernels) unchanged.
Tests:
* ab_fused_fp8_e2e.py — production-equivalent stage1+stage2 A/B
(fused vs unfused vs torch ref).
* ab_fused_fp8_correctness.py — stage1-only fused vs unfused fp8 emit
with byte-match check.
* ab_splitk_correctness.py — kb=2 vs kb=4 split-K self-consistency vs
FP32 partials ref.
* bench_before_after_fusion.py — pre/post fusion + CK comparison.
Co-Authored-By: Claude Opus 4 <noreply@anthropic.com>
On gfx950 the fp8 e4m3fn max is 448, not 240 (the gfx942 e4m3fnuz value).
The fused stage1 epilog was clamping/scaling to ±240, which left half the
fp8 dynamic range unused and caused ~42% e2e error vs the unfused chain
(scales 1.87x = 448/240 too large, fp8 values one exponent step too small).
After this fix, e2e A/B vs the unfused chain agrees within bf16 noise
(fu/un_err% ≈ 2-5% across M ∈ {1,8,16,32,64,256}).
Co-Authored-By: Claude Opus 4 <noreply@anthropic.com>
* test_flydsl_blockscale_moe.py: pass a placeholder uint8 buffer for the new arg_out_scale parameter that compile_moe_blockscale_gemm1 now takes unconditionally (consumed only on the fp8 epilog path). * bench_vs_ck_e2e.py: FlyDSL fused fp8 (stage1+stage2) vs CK two-stage, reports per-stage and total us across M. * gemm_kernels.py: flyc.from_c_void_p was removed upstream; switch to flyc.from_dlpack for both real and fake tensors. Co-Authored-By: Claude Opus 4 <noreply@anthropic.com>
cvt_pk_fp8_f32 does not saturate; out-of-range inputs become fp8 NaN (0x80) and propagate through stage2. Add ±240 v_med3 clamp before the intrinsic (matches the CK pattern in vec_convert.h:46-59). Needed for the split-K (k_batch>1) MoE stage1 path, which still uses the bf16 GEMM + silu_and_mul_fq chain (Phase B-v2 fuses kb=1 only). Note: 240 is the gfx942 e4m3fnuz max; on gfx950 (e4m3fn, max=448) this under-utilizes dynamic range. Same gfx950 fix as 5decccc should be applied here in a follow-up; the clamp itself is correctness-critical on both arches. Co-Authored-By: Claude Opus 4 <noreply@anthropic.com>
Upstream FlyDSL blockscale stage1/stage2 kernels expect activation scales in the transposed [nblk_k, tokens] / [nblk_k_w2, tokens*topk] layout — the same layout asm_stage1 needs. fused_moe_2stages only flipped transpose_scale=True for asm_stage1, so the FlyDSL path silently received the default [tokens, nblk_k] layout. No MLIR/runtime error — just garbage numerics. Production DSR1 TP=8 gsm8k LIMIT=50 with this branch: unfused bf16: 0.02 → 0.98 fused fp8: 0.62 → 0.96 Extend both gates (a1_scale at ~1635, a2_scale fallthrough at ~1760) to also match _flydsl_stage1_wrapper. The fused-fp8 path is unaffected by the a2_scale gate because stage1 writes its own scale buffer in the correct layout (tuple-return branch at ~1701). Co-Authored-By: Claude Opus 4 <noreply@anthropic.com>
Allow disabling FlyDSL for regular A16W16 hgemm dispatch while keeping it enabled for blockscale MoE. Useful when isolating FlyDSL's MoE behavior in end-to-end runs without changing tuning CSVs, and required when the FlyDSL wheel's splitk_hgemm path is incompatible with the current memref-style buffer descriptors used elsewhere. Co-Authored-By: Claude Opus 4 <noreply@anthropic.com>
Squash of post-review fixes: pass raw pointers (from_c_void_p) to all fx.Pointer/ptrtoint kernels — _ptr_view_safe in gemm_kernels (fixes the gfx950 preshuffle a8w8 crash) and the bf16/int4 + fp4 MoE arg builders; correct the stage1 out_scale_sorted slot and use a null FakeTensor ptr for AOT trace; arch-correct FP8 max (240 gfx942 / 448 gfx950) in silu_and_mul_fq; wfp4 scale layout; merge vendored upstream blockscale kernel; drop diagnostic A/B scripts and fix CI lint. Co-Authored-By: Claude Opus 4 <noreply@anthropic.com>
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Title
Summary
Ports the upstream FlyDSL FP8/FP8 + per-1x128 FP32 blockscale MoE GEMM into aiter as a two-stage path wired into the MoE dispatcher, giving a third backend alongside CK and asm for DeepSeek-R1-class workloads on gfx950.
Features
Performance
On DeepSeek-R1-0528 (gfx950, TP=8) the per-M FlyDSL+fallback config is at parity with CK/asm across the mid band (M≈16–1024) and nets a small, accuracy-neutral E2E serving gain. The tuned asm 1-stage kernel still owns the large-M prefill tail (M≥2048).
Table 1 — End-to-end serving (ATOM, DeepSeek-R1-0528, gfx950, TP=8, conc=128, 1280 prompts) on Mi355 node
FlyDSL column = mean of two back-to-back same-kernel runs (range −1.6% to +8.8% output tok/s; spread is TTFT/queue variance at conc=128, not the kernel). FlyDSL routes only at M=1,2,4,8 (split-K), CK/asm fallback elsewhere.
Accuracy-neutral: gsm8k 1.00 flexible / 0.98 strict (50-sample); full-set A/B held at 0.955.
Table 2 — Per-M stage1+stage2 latency, best-tuned (DSR1 shape, lower=better) on Mi355 node
model_dim=7168, inter_dim=256, E=257, topk=9, fp8 e4m3 per-1x128, gfx950. All three backends tuned per-M; ratio = FlyDSL / best(CK, asm).† M≤8 are not publishable performance claims — pure-kernel profiler timing mis-counts split-K atomic-accumulate sub-kernels at small M (non-monotonic values); correctness-checked small-M timing/tuning is a follow-up. M=16 uses the cosine-gated e2e value (≈ parity).
Not yet covered (follow-ups)
The adapter raises
NotImplementedErrorfor CK features not yet ported: SwiGLU-step (clipped) activation, padded shapes (M/N/K padding), fused bias / multi-D elementwise, compute-optimized pipelines (CK v2–v5), and pipeline scheduler choice. Also open: reliable small-M split-K timing + tuning, and CSV-driven multi-M routing inaiter/fused_moe.pyfor non-DSR1 shapes.Testing
AITER_RUN_PERF=1)op_tests/op_benchmarks/hip/bench_flydsl_moe_blockscale.py)