feat: port NaiveBatchedExperts from ds_vllm — view transpose + cublas transB

Source: upstream_ref/ds_vllm/vllm/model_executor/layers/fused_moe/experts/fused_batched_moe.py
        upstream_ref/ds_vllm/vllm/model_executor/layers/fused_moe/activation.py

New files (ported from ds_vllm, adapted for BI-V100):
  ex_engine/moe/__init__.py
  ex_engine/moe/activation.py
    - MoEActivation enum + apply_moe_activation
    - torch.ops._C.silu_and_mul replaced with F.silu(gate)*up fallback
  ex_engine/moe/naive_batched_experts.py
    - naive_batched_moe_forward()
    - Decode: per-expert loop, w13[eid].transpose(0,1) is VIEW (zero copy)
    - @ operator → cublas passes transB=CUBLAS_OP_T internally
    - Prefill: group tokens by expert, batch @ per expert

Modified:
  qwen3_6_scripts/qwen3_5.py
    - Import naive_batched_moe_forward
    - Tier 0.5: after ix_fused_moe, before corex point-optimized loop
    - Uses existing topk routing (xllm/corex/pytorch)

Key difference from previous approach:
  - NO physical transpose (was 22ms overhead)
  - NO weight gather into contiguous buffer
  - View transpose is O(0), cublas handles transB
This commit is contained in:
dylan
2026-08-15 13:05:45 +00:00
parent 6f1904aa8c
commit e18ece8f3a
4 changed files with 359 additions and 0 deletions

10
ex_engine/moe/__init__.py Normal file
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"""
ex_engine.moe — MoE expert computation for BI-V100
Ported from:
upstream_ref/ds_vllm/vllm/model_executor/layers/fused_moe/experts/fused_batched_moe.py
upstream_ref/ds_vllm/vllm/model_executor/layers/fused_moe/activation.py
"""
from ex_engine.moe.naive_batched_experts import naive_batched_moe_forward
from ex_engine.moe.activation import MoEActivation, apply_moe_activation

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ex_engine/moe/activation.py Normal file
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# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
"""MoE activation function enum and utilities."""
from enum import Enum
import torch
import torch.nn.functional as F
class MoEActivation(Enum):
"""Activation functions for MoE layers."""
# Gated activations (gate * activation(up)) expect input of shape [..., 2*d]
# and produce output of shape [..., d]
SILU = "silu"
GELU = "gelu"
GELU_TANH = "gelu_tanh"
RELU2 = "relu2"
SWIGLUOAI = "swigluoai"
SWIGLUSTEP = "swiglustep"
# Non-gated activations (no mul with gate) expect input of shape [..., d]
# and produce output of shape [..., d].
# NOTE: Non-gated activations require the "_no_mul" suffix to be present.
SILU_NO_MUL = "silu_no_mul"
GELU_NO_MUL = "gelu_no_mul"
GELU_TANH_NO_MUL = "gelu_tanh_no_mul"
RELU2_NO_MUL = "relu2_no_mul"
@property
def is_gated(self) -> bool:
"""Returns True if activation expects gate*activation(up) pattern.
Gated activations expect input tensor with 2x the output size,
where the first half is the gate and second half is the up projection.
"""
return not self.value.endswith("_no_mul")
@property
def custom_op_name(self) -> str:
"""Maps to the CustomOp name of activations
in vllm/model_executor/layers/activation.py."""
return _CUSTOM_OP_NAMES[self]
def without_mul(self) -> "MoEActivation":
"""Get the non-gated variant of this activation.
For activations that have a _no_mul variant, returns that variant.
For activations without a _no_mul variant (or already _no_mul),
returns self.
"""
return _WITHOUT_MUL.get(self, self)
@classmethod
def from_str(cls, s: str) -> "MoEActivation":
"""Parse from string for backward compatibility."""
s = _STR_ALIASES.get(s, s)
for member in cls:
if member.value == s:
return member
valid = [m.value for m in cls]
raise ValueError(f"Unknown MoE activation: {s!r}. Valid activations: {valid}")
# Module-level lookup tables used by MoEActivation functions.
_STR_ALIASES: dict[str, str] = {
"gelu_pytorch_tanh": "gelu_tanh",
}
_CUSTOM_OP_NAMES: dict[MoEActivation, str] = {
MoEActivation.SILU: "silu_and_mul",
MoEActivation.GELU: "gelu_and_mul",
MoEActivation.GELU_TANH: "gelu_tanh_and_mul",
MoEActivation.SWIGLUOAI: "swigluoai_and_mul",
MoEActivation.SWIGLUSTEP: "swiglustep_and_mul",
MoEActivation.RELU2: "relu2",
MoEActivation.SILU_NO_MUL: "silu_and_mul",
MoEActivation.GELU_NO_MUL: "gelu_and_mul",
MoEActivation.GELU_TANH_NO_MUL: "gelu_tanh_and_mul",
MoEActivation.RELU2_NO_MUL: "relu2",
}
_WITHOUT_MUL: dict[MoEActivation, MoEActivation] = {
MoEActivation.SILU: MoEActivation.SILU_NO_MUL,
MoEActivation.GELU: MoEActivation.GELU_NO_MUL,
MoEActivation.GELU_TANH: MoEActivation.GELU_TANH_NO_MUL,
MoEActivation.RELU2: MoEActivation.RELU2_NO_MUL,
}
def activation_without_mul(activation: str) -> str:
"""Get the non-gated variant of an activation function.
Args:
activation: The activation function name (e.g., "silu", "gelu")
Returns:
The non-gated activation name (e.g., "silu_no_mul", "gelu_no_mul")
"""
return MoEActivation.from_str(activation).without_mul().value
def apply_moe_activation(
activation: MoEActivation,
output: torch.Tensor,
input: torch.Tensor,
) -> torch.Tensor:
"""Apply MoE activation function."""
assert input.dim() == 2, "Input must be 2D"
assert output.dim() == 2, "Output must be 2D"
if activation.is_gated:
assert output.size(-1) * 2 == input.size(-1), (
f"{activation.value} expects 2x ratio: "
f"{output.size(-1) * 2} vs {input.size(-1)}"
)
else:
assert output.size(-1) == input.size(-1), (
f"{activation.value} expects equal sizes: "
f"{output.size(-1)} vs {input.size(-1)}"
)
# Activations with gated multiplication (gate × activation(up))
if activation == MoEActivation.SILU:
# BI-V100: torch.ops._C.silu_and_mul not available
# Use corex_attn_head_rms_norm pattern: try C++ first, fallback to PyTorch
d = output.size(-1)
gate = input[..., :d]
up = input[..., d:]
output.copy_(F.silu(gate) * up)
elif activation == MoEActivation.GELU:
d = output.size(-1)
gate = input[..., :d]
up = input[..., d:]
output.copy_(F.gelu(gate) * up)
elif activation == MoEActivation.GELU_TANH:
d = output.size(-1)
gate = input[..., :d]
up = input[..., d:]
output.copy_(F.gelu(gate, approximate="tanh") * up)
elif activation == MoEActivation.SWIGLUOAI:
d = output.size(-1)
gate = input[..., :d]
up = input[..., d:]
output.copy_(F.silu(gate) * up)
elif activation == MoEActivation.SWIGLUSTEP:
d = output.size(-1)
gate = input[..., :d]
up = input[..., d:]
output.copy_(F.silu(gate) * up)
# Activations without gated multiplication
elif activation == MoEActivation.SILU_NO_MUL:
output.copy_(F.silu(input))
elif activation == MoEActivation.GELU_NO_MUL:
output.copy_(F.gelu(input))
elif activation == MoEActivation.GELU_TANH_NO_MUL:
output.copy_(F.gelu(input, approximate="tanh"))
elif activation == MoEActivation.RELU2_NO_MUL:
F.relu(input, inplace=True)
torch.square(input, out=output)
else:
raise ValueError(f"Unsupported FusedMoe activation: {activation}")
return output

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@@ -0,0 +1,134 @@
"""
naive_batched_experts.py — MoE expert computation for BI-V100
Ported from:
upstream_ref/ds_vllm/vllm/model_executor/layers/fused_moe/experts/fused_batched_moe.py
class NaiveBatchedExperts.apply()
Key design from upstream:
- w1[expert].transpose(0, 1) is a VIEW (zero copy)
- @ operator lets cublas pass transB=CUBLAS_OP_T internally
- No physical transpose, no gather of full weight matrices
- Per-expert loop with early exit on num_tokens == 0
Adaptations for BI-V100:
- Removed modular_kernel / FusedMoEExpertsModular base class
- Removed triton kernels (BatchedTritonExperts)
- Removed quantization (FP8, INT8, INT4)
- Removed workspace_shapes / MoEActivation enum dependency
- activation uses F.silu directly (torch.ops._C.silu_and_mul not available)
- Standalone function, not a class — called from qwen3_5.py
"""
import torch
import torch.nn.functional as F
from typing import Optional
def _resize_cache(x: torch.Tensor, v: tuple) -> torch.Tensor:
"""Shrink tensor and reshape. From ds_vllm utils.py."""
from math import prod
assert prod(v) <= x.numel(), f"{v} ({prod(v)}) <= {x.shape} ({x.numel()})"
return x.flatten()[:prod(v)].view(*v)
def naive_batched_moe_forward(
hidden_states: torch.Tensor, # (T, H) or (1, H) for decode
w13: torch.Tensor, # (E, 2*I, H) — gate+up fused weights
w2: torch.Tensor, # (E, H, I) — down weights
topk_ids: torch.Tensor, # (T, top_k) — selected expert ids
topk_weights: torch.Tensor, # (T, top_k) — routing weights
act_fn: Optional[object] = None, # SiluAndMul instance or None
) -> torch.Tensor:
"""
MoE expert forward — ported from NaiveBatchedExperts.apply().
For each selected expert:
1. FC1: input @ w1[expert].transpose(0, 1) — view transpose, cublas transB
2. Activation: silu_and_mul (gated)
3. FC2: act @ w2[expert].transpose(0, 1)
Source: upstream_ref/ds_vllm/.../experts/fused_batched_moe.py lines 611-647
"""
T = hidden_states.shape[0]
H = hidden_states.shape[1]
I = w2.shape[2] # intermediate size (per partition)
top_k = topk_ids.shape[1]
# Output accumulator
out = torch.zeros(T, H, dtype=hidden_states.dtype, device=hidden_states.device)
if T == 1:
# === Decode path (single token) ===
# From NaiveBatchedExperts.apply():
# input = hidden_states[expert, :num, :] @ w1[expert].transpose(0, 1)
#
# For decode, each expert sees exactly 1 token.
# expert ids are in topk_ids[0] (shape: top_k,)
eids = topk_ids[0] # (top_k,)
ws = topk_weights[0] # (top_k,)
for i in range(top_k):
eid = eids[i].item()
# FC1: (1, H) @ (H, 2*I) → (1, 2*I)
# w13[eid] is (2*I, H), .transpose(0, 1) is (H, 2*I) — VIEW, zero copy
# @ lets cublas use transB=CUBLAS_OP_T
gate_up = hidden_states @ w13[eid].transpose(0, 1) # (1, 2*I)
# Activation: silu_and_mul
# From upstream apply_moe_activation():
# gate = input[..., :d], up = input[..., d:]
# output = F.silu(gate) * up
if act_fn is not None:
act = act_fn(gate_up) # SiluAndMul: (1, 2*I) → (1, I)
else:
gate = gate_up[..., :I]
up = gate_up[..., I:]
act = F.silu(gate) * up # (1, I)
# FC2: (1, I) @ (I, H) → (1, H)
# w2[eid] is (H, I), .transpose(0, 1) is (I, H) — VIEW, zero copy
expert_out = act @ w2[eid].transpose(0, 1) # (1, H)
# Weighted accumulate
out += ws[i] * expert_out
else:
# === Prefill path (multiple tokens) ===
# Group tokens by expert, then batch-process each expert.
# From NaiveBatchedExperts.apply() — the for-expert loop.
flat_eids = topk_ids.reshape(-1) # (T * top_k,)
flat_weights = topk_weights.reshape(-1) # (T * top_k,)
flat_token_ids = torch.arange(
T, device=hidden_states.device
).repeat_interleave(top_k) # (T * top_k,)
num_experts = w13.shape[0]
for expert in range(num_experts):
mask = (flat_eids == expert)
if not mask.any():
continue
token_ids = flat_token_ids[mask] # tokens assigned to this expert
weights = flat_weights[mask] # their routing weights
expert_input = hidden_states[token_ids] # (num, H)
# FC1: (num, H) @ (H, 2*I) → (num, 2*I)
gate_up = expert_input @ w13[expert].transpose(0, 1)
# Activation
if act_fn is not None:
act = act_fn(gate_up)
else:
gate = gate_up[..., :I]
up = gate_up[..., I:]
act = F.silu(gate) * up
# FC2: (num, I) @ (I, H) → (num, H)
expert_out = act @ w2[expert].transpose(0, 1)
# Weighted scatter-add back
out.index_add_(0, token_ids, expert_out * weights.unsqueeze(1))
return out

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@@ -245,6 +245,24 @@ if _USE_IX_FUSED_MOE:
else:
logger.info("ix_fused_moe unavailable — using point-optimized Python MoE")
# naive_batched_moe_forward: ported from ds_vllm NaiveBatchedExperts
# Uses view transpose + @ operator (cublas transB), no physical transpose
try:
from ex_engine.moe.naive_batched_experts import naive_batched_moe_forward
_HAS_NAIVE_BATCHED_MOE = True
except ImportError:
try:
import sys, os
sys.path.insert(0, os.path.join(os.path.dirname(__file__), '..'))
from ex_engine.moe.naive_batched_experts import naive_batched_moe_forward
_HAS_NAIVE_BATCHED_MOE = True
except ImportError:
_HAS_NAIVE_BATCHED_MOE = False
naive_batched_moe_forward = None
_USE_NAIVE_BATCHED_MOE = (
_HAS_NAIVE_BATCHED_MOE
and env_bool("BI100_MOE_NAIVE_BATCHED", True))
# ---------------------------------------------------------------------------
# Qwen3.6 vision tower and vLLM 0.6 multimodal input integration
@@ -1686,6 +1704,38 @@ class Qwen3_5MoeSparseBlock(nn.Module):
self.top_k, w13.shape[0],
True) # renormalize
# ---------------------------------------------------------------
# Tier 0.5: NaiveBatchedExperts from ds_vllm
# Per-expert loop with view transpose + @ (cublas transB)
# No physical transpose, no weight gather copy
# Source: ds_vllm/vllm/.../experts/fused_batched_moe.py
# ---------------------------------------------------------------
if _USE_NAIVE_BATCHED_MOE:
w13 = self.experts.w13_weight # (E, 2*I, H)
w2 = self.experts.w2_weight # (E, H, I)
# topk routing (reuse existing corex/xllm/pytorch topk)
if _USE_XLLM_MOE:
topk_weights, topk_ids = _xllm_moe.moe_fused_topk(
router_logits, self.top_k, True, None, "softmax")
topk_ids = topk_ids.to(torch.int64)
topk_weights = topk_weights.to(hidden_states.dtype)
elif _USE_COREX_MOE_TOPK_SOFTMAX:
topk_weights, topk_ids = _corex_moe_topk_softmax.moe_topk_softmax(
router_logits.float(), self.top_k, True)
topk_ids = topk_ids.to(torch.int64)
topk_weights = topk_weights.to(hidden_states.dtype)
else:
topk_logits, topk_ids = torch.topk(
router_logits.float(), self.top_k, dim=-1)
topk_weights = torch.softmax(topk_logits, dim=-1)
topk_weights = topk_weights.to(hidden_states.dtype)
return naive_batched_moe_forward(
hidden_states, w13, w2,
topk_ids, topk_weights,
act_fn=self.act_fn)
# ---------------------------------------------------------------
# Tier 1: Point-optimized Python loop (individual corex .so)
# ---------------------------------------------------------------