[AMD] DeepSeek-V4: route decode wo_a bf16 batched matmul to aiter batched_gemm_bf16 (#33313)

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Co-authored-by: Thomas Wang <thomawan@amd.com>
This commit is contained in:
karverma-amd
2026-08-19 03:04:48 -07:00
committed by GitHub
co-authored by Claude Opus 4.8 Thomas Wang
parent ce1830c59b
commit f446e853e7
3 changed files with 293 additions and 1 deletions
+4
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@@ -1282,6 +1282,10 @@ class Envs:
# cache, GEMM, and distributed
SGLANG_OPT_FP8_WO_A_GEMM = EnvBool(True)
# Route the decode wo_a bf16 batched matmul off rocBLAS/Tensile onto aiter's
# tuned batched_gemm_bf16 (gfx95). Off by default; see deepseek_v4.py
# _apply_wo_a_bf16_matmul.
SGLANG_OPT_USE_AITER_BATCHED_GEMM = EnvBool(False)
SGLANG_OPT_BF16_FP32_GEMM_ALGO = EnvStr("cublas")
SGLANG_OPT_FUSE_WQA_WKV = EnvBool(True)
SGLANG_OPT_USE_MULTI_STREAM_OVERLAP = EnvBool(True)
+86 -1
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@@ -311,6 +311,89 @@ if _use_aiter:
from aiter.ops.triton.fused_fp8_quant import fused_rms_fp8_group_quant
def _wo_a_aiter_gemm_eligible(
flag: bool, use_aiter: bool, is_hip: bool, is_gfx95: bool
) -> bool:
"""Static eligibility for the aiter ``wo_a`` reroute.
Folds the opt-in flag, the global ``SGLANG_USE_AITER`` switch, and the
HIP/gfx95 platform gates into one predicate. Evaluated once at import (see
``_wo_a_aiter_batched_gemm_enabled``) so none of it runs on the per-token
decode critical path.
"""
return bool(flag and use_aiter and is_hip and is_gfx95)
# Read the opt-in flag and import the aiter kernel ONCE at module import: the
# decode ``wo_a`` matmul runs per layer/token on the critical path, so it must
# not pay an ``EnvBool.get()`` plus a function-local import on every call. If the
# path is eligible but the kernel import fails, disable it here and fall back to
# the einsum for the process (logged once) instead of retrying every step.
_wo_a_aiter_batched_gemm_enabled = _wo_a_aiter_gemm_eligible(
envs.SGLANG_OPT_USE_AITER_BATCHED_GEMM.get(),
_use_aiter,
_is_hip,
_is_gfx95_supported,
)
_wo_a_batched_gemm_bf16 = None
if _wo_a_aiter_batched_gemm_enabled:
try:
from aiter.ops.triton.gemm.batched.batched_gemm_bf16 import (
batched_gemm_bf16 as _wo_a_batched_gemm_bf16,
)
except Exception as err: # pragma: no cover - env-dependent
_wo_a_aiter_batched_gemm_enabled = False
logger.warning(
"aiter wo_a batched_gemm_bf16 import failed; using einsum for wo_a "
"for the rest of this process: %s",
err,
)
# Flipped once if the (already-imported) aiter kernel raises at runtime, so a
# per-call kernel failure falls back to the einsum for the rest of the process
# instead of re-raising (and re-logging) on every layer/token.
_wo_a_aiter_batched_gemm_disabled = False
def _apply_wo_a_bf16_matmul(
o: torch.Tensor, wo_a: torch.Tensor, is_decode: bool
) -> torch.Tensor:
"""wo_a (attn output -> o_proj low-rank) bf16 batched matmul.
``o`` is ``[T, G, D]`` (tokens, groups, head_dim) and ``wo_a`` is
``[G, R, D]`` (groups, o_lora_rank, head_dim); the result is ``[T, G, R]``.
Dispatch contract: on the decode path, when the reroute is enabled
(``_wo_a_aiter_batched_gemm_enabled``, computed once at import) and has not
been disabled by a prior runtime failure, call the pre-imported aiter
``batched_gemm_bf16`` (``Y[i] = X[i] @ W[i]^T``). Otherwise -- prefill, any
gate off, or after a failure -- use the numerically-equivalent
``torch.einsum("tgd,grd->tgr", ...)``. The first runtime kernel failure
disables the reroute for the process (logged once).
"""
global _wo_a_aiter_batched_gemm_disabled
if (
is_decode
and _wo_a_aiter_batched_gemm_enabled
and not _wo_a_aiter_batched_gemm_disabled
):
try:
# aiter batched_gemm_bf16: XQ[B,M,K] @ WQ[B,N,K]^T -> [B,M,N].
# Here batch = group G: XQ = o.transpose(0,1) [G,T,D], WQ = wo_a
# [G,R,D] -> [G,T,R] -> transpose back to [T,G,R].
xq = o.transpose(0, 1).contiguous()
y = _wo_a_batched_gemm_bf16(xq, wo_a, dtype=torch.bfloat16)
return y.transpose(0, 1).contiguous()
except Exception as err:
_wo_a_aiter_batched_gemm_disabled = True
logger.warning(
"aiter wo_a batched_gemm_bf16 failed; disabling the reroute and "
"falling back to einsum for the rest of this process: %s",
err,
)
return torch.einsum("tgd,grd->tgr", o, wo_a)
def _fused_rmsnorm_fp8_quant(hidden_states, weight, eps):
x_quant, x_bf16, _, _ = fused_rms_fp8_group_quant(
hidden_states,
@@ -1582,7 +1665,9 @@ class MQALayer(MqaAttentionBase):
o = output
else:
wo_a = self.wo_a.weight.view(self.n_local_groups, self.o_lora_rank, -1)
o = torch.einsum("tgd,grd->tgr", o, wo_a)
o = _apply_wo_a_bf16_matmul(
o, wo_a, is_decode=forward_batch.forward_mode.is_decode()
)
o, _ = self.wo_b(o.flatten(1))
if self.attn_tp_size > 1 and self.attn_tp_size < get_parallel().tp_size:
@@ -0,0 +1,203 @@
"""Tests for the DeepSeek-V4 decode ``wo_a`` bf16 batched-matmul routing.
Covers ``deepseek_v4._apply_wo_a_bf16_matmul``, which (opt-in via
``SGLANG_OPT_USE_AITER_BATCHED_GEMM`` on HIP/gfx95) routes the MLA output-absorb
bf16 GEMM off the rocBLAS/Tensile ``Cijk_*`` batched GEMM onto aiter's tuned
``batched_gemm_bf16``, with an einsum fallback.
The opt-in flag and the aiter kernel are resolved ONCE at module import
(``_wo_a_aiter_gemm_eligible`` -> ``_wo_a_aiter_batched_gemm_enabled`` and the
pre-imported ``_wo_a_batched_gemm_bf16``) so the decode critical path pays no
``EnvBool.get()`` or function-local import per token. The tests therefore drive
those cached module globals directly.
Validates:
1. Static eligibility -- ``_wo_a_aiter_gemm_eligible`` is true only when the
flag, the global ``SGLANG_USE_AITER`` switch, HIP, and gfx95 are all set
(table-driven).
2. Dispatch/gating -- with the reroute disabled, or on prefill
(``is_decode=False``), the plain ``torch.einsum("tgd,grd->tgr", ...)`` path
runs (bit-identical to the old code); only decode + enabled hits the kernel.
3. Fallback -- a runtime kernel failure degrades to the einsum and disables the
reroute for the rest of the process (no per-call retry / log spam on the
decode critical path).
4. Numerics -- on gfx95 with aiter, the aiter kernel is genuinely used and its
result matches the einsum within bf16 tolerance across ``T/G/D/R`` shapes
(the PR's model-free bit-check).
deepseek_v4 pulls in the full model stack, so this is registered as an AMD GPU
test and only imported behind ``is_hip()`` -- matching the existing AMD aiter
op tests.
"""
import unittest
from unittest import mock
import torch
from sglang.srt.utils.common import is_hip
from sglang.test.ci.ci_register import register_amd_ci
register_amd_ci(est_time=60, suite="stage-b-test-1-gpu-small-amd-mi35x")
@unittest.skipUnless(is_hip(), "wo_a batched_gemm_bf16 routing requires ROCm")
class TestWoABf16BatchedGemm(unittest.TestCase):
@classmethod
def setUpClass(cls):
# Import the heavy model module only on a GPU runner (see module docstring).
from sglang.srt.models import deepseek_v4 as dsv4
cls.dsv4 = dsv4
cls.device = "cuda" # torch maps "cuda" onto the ROCm HIP device
def setUp(self):
torch.manual_seed(0)
# The one-shot runtime-disable flag is process-global; reset it so a
# failure case in one test cannot leak into another.
self.dsv4._wo_a_aiter_batched_gemm_disabled = False
def _rand(self, T, G, D, R):
o = torch.randn(T, G, D, device=self.device, dtype=torch.bfloat16)
wo_a = torch.randn(G, R, D, device=self.device, dtype=torch.bfloat16)
return o, wo_a
@staticmethod
def _einsum(o, wo_a):
return torch.einsum("tgd,grd->tgr", o, wo_a)
def _require_gfx95_aiter(self):
if not self.dsv4._is_gfx95_supported:
self.skipTest("aiter batched_gemm_bf16 is gfx95-only")
try:
from aiter.ops.triton.gemm.batched.batched_gemm_bf16 import ( # noqa: F401
batched_gemm_bf16,
)
except Exception as err: # pragma: no cover - env-dependent
self.skipTest(f"aiter batched_gemm_bf16 unavailable: {err}")
# ------------------------------------------------------ static eligibility
def test_eligibility_gating(self):
# The reroute activates only when the opt-in flag, the global aiter
# switch, HIP, and gfx95 are ALL set -- resolved once at import.
eligible = self.dsv4._wo_a_aiter_gemm_eligible
base = dict(flag=True, use_aiter=True, is_hip=True, is_gfx95=True)
self.assertTrue(eligible(**base))
for off in ("flag", "use_aiter", "is_hip", "is_gfx95"):
with self.subTest(disabled=off):
self.assertFalse(eligible(**{**base, off: False}))
# ---------------------------------------------------------- dispatch gating
def test_dispatch_gating(self):
# Given the cached ``enabled`` bool and the forward mode, the kernel is
# hit only on decode + enabled; every other case takes the einsum.
o, wo_a = self._rand(8, 4, 128, 32)
ref = self._einsum(o, wo_a)
def _fake_kernel(xq, w, dtype): # [G,T,D] @ [G,R,D]^T -> [G,T,R]
fake_kernel.calls += 1
return torch.einsum("gtd,grd->gtr", xq, w).to(dtype)
fake_kernel = _fake_kernel
for enabled, is_decode, expect_kernel in (
(True, True, True),
(True, False, False), # prefill keeps the einsum
(False, True, False), # reroute off -> einsum
(False, False, False),
):
with self.subTest(enabled=enabled, is_decode=is_decode):
fake_kernel.calls = 0
with (
mock.patch.object(
self.dsv4, "_wo_a_aiter_batched_gemm_enabled", enabled
),
mock.patch.object(
self.dsv4, "_wo_a_batched_gemm_bf16", fake_kernel
),
mock.patch("torch.einsum", wraps=torch.einsum) as spy,
):
out = self.dsv4._apply_wo_a_bf16_matmul(
o, wo_a, is_decode=is_decode
)
self.assertEqual(out.shape, (8, 4, 32))
if expect_kernel:
self.assertEqual(fake_kernel.calls, 1)
# einsum only ran here as the fake kernel's own impl.
else:
self.assertEqual(fake_kernel.calls, 0)
spy.assert_called_once()
self.assertTrue(torch.equal(out, ref))
# ---------------------------------------------------------------- fallback
def test_runtime_failure_falls_back_and_disables_reroute(self):
o, wo_a = self._rand(8, 4, 128, 32)
call_count = {"n": 0}
def _boom(*args, **kwargs):
call_count["n"] += 1
raise RuntimeError("kernel missing")
with (
mock.patch.object(self.dsv4, "_wo_a_aiter_batched_gemm_enabled", True),
mock.patch.object(self.dsv4, "_wo_a_batched_gemm_bf16", _boom),
):
out = self.dsv4._apply_wo_a_bf16_matmul(o, wo_a, is_decode=True)
# Failure inside the aiter branch must not raise and must match einsum.
self.assertEqual(out.shape, (8, 4, 32))
self.assertTrue(torch.equal(out, self._einsum(o, wo_a)))
# The reroute is disabled after the first failure, so a subsequent
# decode step does not retry the broken kernel (no per-call log spam
# on the critical path).
self.assertTrue(self.dsv4._wo_a_aiter_batched_gemm_disabled)
out2 = self.dsv4._apply_wo_a_bf16_matmul(o, wo_a, is_decode=True)
self.assertTrue(torch.equal(out2, self._einsum(o, wo_a)))
self.assertEqual(call_count["n"], 1) # kernel attempted exactly once
# ---------------------------------------------------------------- numerics
def test_aiter_matches_einsum_across_shapes(self):
self._require_gfx95_aiter()
from aiter.ops.triton.gemm.batched.batched_gemm_bf16 import batched_gemm_bf16
# (T tokens, G groups, D head_dim, R o_lora_rank)
shapes = [
(1, 4, 128, 32),
(8, 8, 128, 64),
(37, 4, 192, 32),
(128, 2, 128, 16),
]
for T, G, D, R in shapes:
with self.subTest(T=T, G=G, D=D, R=R):
o, wo_a = self._rand(T, G, D, R)
ref = self._einsum(o, wo_a).float()
with (
mock.patch.object(
self.dsv4, "_wo_a_aiter_batched_gemm_enabled", True
),
mock.patch.object(
self.dsv4, "_wo_a_batched_gemm_bf16", batched_gemm_bf16
),
mock.patch("torch.einsum", wraps=torch.einsum) as spy,
):
out = self.dsv4._apply_wo_a_bf16_matmul(o, wo_a, is_decode=True)
# The aiter kernel -- not the einsum fallback -- must have run,
# otherwise this check would be trivially satisfied.
spy.assert_not_called()
self.assertEqual(out.shape, (T, G, R))
self.assertEqual(out.dtype, torch.bfloat16)
rel = ((out.float() - ref).abs() / (ref.abs() + 1e-6)).max().item()
self.assertLessEqual(rel, 5e-4)
if __name__ == "__main__":
unittest.main()