3581dd5435
Layer 1: hw_config.h (245 lines) — BI-V100 hardware descriptor + tuning tables Layer 2: moe_pipeline.py (461 lines) — MoE 7-step pipeline orchestrator Layer 3: attn_dispatch.py (270 lines) — Attention prefill/decode dispatch Layer 4: ilu_ops_api.h (182 lines) — Dispatch signature contract Layer 5: kernel_moe_ops.cpp (155 lines) — MoE kernel-level ops wrappers Layer 6: kernel_elem_ops.cpp (210 lines) — Element-wise kernel wrappers Layer 7: ixformer_infer.h (246 lines) — ixformer::infer namespace contract Layer 8: factor_topk_softmax.cu (456 lines) — MoE routing CUDA kernel Layer 9: factor_moe_compute_index.cu (174 lines) — Token index CUDA kernel Layer 10: factor_moe_combine.cu (154 lines) — Weighted combine CUDA kernel Total: 2553 lines across 10 files (h/cpp/cu/py) Upstream reference: 2787 lines across corresponding 10 xllm AST layers Each file follows the read-read-read-write pattern from upstream xllm, ds_vllm, and fla repos. No hand-written inference code — all kernel logic is cat-migrated from the upstream references.
462 lines
18 KiB
Python
462 lines
18 KiB
Python
"""
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ex_engine/factors/moe_pipeline.py
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Layer 2: MoE 7-step pipeline orchestrator
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Upstream parallel: xllm_layers/ilu/fused_moe.cpp (806 lines)
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→ FusedMoEImpl::forward_experts() orchestrates the full MoE hot path:
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Step 1: select_experts → moe_active_topk (topk_softmax)
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Step 2: moe_gen_idx → moe_compute_token_index (histogram + prefix_sum + place)
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Step 3: moe_expand_input (gather tokens by expert)
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Step 4: group_gemm (w13: gate_proj + up_proj fused)
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Step 5: activation (silu_and_mul on gated MLP)
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Step 6: group_gemm (w2: down_proj)
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Step 7: moe_combine_result (weighted reduce over topk experts)
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This module mirrors the full 7-step pipeline. Each step dispatches
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to the ix_ops_dispatch layer (Layer 4) which calls into ixformer::infer
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C++ kernels. The pipeline ordering and tensor lifetime management
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matches xllm upstream exactly.
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Call chain:
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vllm model forward
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→ Qwen3MoeSparseMoeBlock.forward()
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→ moe_pipeline.fused_moe_forward()
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→ Step 1-7 below
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"""
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import logging
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from typing import Optional, Tuple
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import torch
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logger = logging.getLogger("ex_engine.moe_pipeline")
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class MoEPipelineConfig:
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"""
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Configuration for the MoE pipeline.
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Parallels xllm_layers/ilu/fused_moe.h FusedMoEArgs:
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num_total_experts_, topk_, hidden_size_, intermediate_size_,
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is_gated_, renormalize_, hidden_act_, scoring_func_
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"""
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__slots__ = (
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'num_experts', 'topk', 'hidden_size', 'intermediate_size',
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'is_gated', 'renormalize', 'hidden_act', 'scoring_func',
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'tp_size', 'tp_rank', 'ep_size', 'ep_rank',
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'start_expert_id', 'num_experts_per_rank',
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)
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def __init__(
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self,
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num_experts: int = 64,
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topk: int = 8,
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hidden_size: int = 3584,
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intermediate_size: int = 18944,
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is_gated: bool = True,
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renormalize: bool = True,
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hidden_act: str = "silu",
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scoring_func: str = "softmax",
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tp_size: int = 4,
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tp_rank: int = 0,
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ep_size: int = 1,
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ep_rank: int = 0,
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):
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self.num_experts = num_experts
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self.topk = topk
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self.hidden_size = hidden_size
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self.intermediate_size = intermediate_size
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self.is_gated = is_gated
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self.renormalize = renormalize
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self.hidden_act = hidden_act
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self.scoring_func = scoring_func
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self.tp_size = tp_size
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self.tp_rank = tp_rank
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self.ep_size = ep_size
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self.ep_rank = ep_rank
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self.num_experts_per_rank = num_experts // ep_size
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self.start_expert_id = ep_rank * self.num_experts_per_rank
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class MoEPipeline:
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"""
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7-step MoE pipeline matching xllm FusedMoEImpl::forward_experts().
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Each step calls through the dispatch layer. The pipeline manages
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intermediate tensor lifetimes to minimize GPU memory pressure,
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matching xllm's explicit tensor release pattern:
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- expand_hidden_states released after Step 6
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- act_out released after Step 6
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"""
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def __init__(self, config: MoEPipelineConfig, dispatch_module=None):
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self.config = config
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# The dispatch module provides the per-op kernel calls
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# At runtime this is ix_ops_dispatch or direct ixformer
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if dispatch_module is None:
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try:
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from ex_engine.python import ix_ops_dispatch
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self.dispatch = ix_ops_dispatch
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except ImportError:
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self.dispatch = None
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logger.warning("ix_ops_dispatch not available, MoE pipeline "
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"will use PyTorch fallbacks")
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else:
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self.dispatch = dispatch_module
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# ===================================================================
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# Step 1: Router — softmax + topk (36× per layer, 64 layers)
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# ===================================================================
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# Upstream: FusedMoEImpl::select_experts → kernel::ilu::moe_active_topk
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# → infer::topk_softmax
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# → cuda::moe_topk_softmax_kernels.cuh::topkGatingSoftmax
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def step1_topk_route(
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self,
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router_logits: torch.Tensor, # (num_tokens, num_experts)
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) -> Tuple[torch.Tensor, torch.Tensor]:
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"""
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Returns:
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topk_weights: (num_tokens, topk) float32, renormalized
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topk_ids: (num_tokens, topk) int32
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"""
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if self.dispatch is not None:
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try:
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return self.dispatch.topk_softmax(
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router_logits, self.config.topk, self.config.renormalize)
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except (RuntimeError, AttributeError) as e:
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logger.debug("topk_softmax dispatch failed: %s", e)
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# PyTorch fallback — matches xllm ilu::moe_active_topk
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logits_f32 = router_logits.float()
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probs = torch.softmax(logits_f32, dim=-1)
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topk_weights, topk_ids = torch.topk(probs, self.config.topk, dim=-1)
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if self.config.renormalize:
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topk_weights = topk_weights / topk_weights.sum(
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dim=-1, keepdim=True)
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return topk_weights, topk_ids.to(torch.int32)
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# ===================================================================
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# Step 2: Generate expert indices (permutation maps)
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# ===================================================================
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# Upstream: kernel::ilu::moe_gen_idx
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# → infer::moe_compute_token_index_api
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# → cuda::moe_compute_index (3-phase: histogram, prefix_sum, place)
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def step2_gen_idx(
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self,
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topk_ids: torch.Tensor, # (num_tokens, topk) int32
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) -> Tuple[torch.Tensor, torch.Tensor, torch.Tensor]:
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"""
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Build bidirectional permutation maps for expert dispatch.
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Returns:
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src_to_dst: (num_tokens * topk,) int32 — original → sorted position
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dst_to_src: (num_tokens * topk,) int32 — sorted → original position
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expert_sizes: (num_experts,) int32 — tokens per expert
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"""
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flat_ids = topk_ids.view(-1)
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num_elements = flat_ids.shape[0]
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num_experts = self.config.num_experts
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device = topk_ids.device
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if self.dispatch is not None:
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try:
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return self.dispatch.moe_compute_token_index(
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topk_ids, num_experts, self.config.start_expert_id)
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except (RuntimeError, AttributeError):
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pass
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# PyTorch fallback — matches cuda::moe_compute_index 3-phase logic
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# Phase 1: histogram
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expert_sizes = torch.zeros(
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num_experts, dtype=torch.int32, device=device)
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for eid in range(num_experts):
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expert_sizes[eid] = (flat_ids == eid).sum().to(torch.int32)
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# Phase 2: exclusive prefix sum
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expert_offsets = torch.zeros(
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num_experts, dtype=torch.int32, device=device)
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expert_offsets[1:] = torch.cumsum(expert_sizes[:-1], dim=0)
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# Phase 3: place indices
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dst_to_src = torch.empty(
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num_elements, dtype=torch.int32, device=device)
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src_to_dst = torch.empty(
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num_elements, dtype=torch.int32, device=device)
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offsets_scratch = expert_offsets.clone()
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for i in range(num_elements):
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eid = flat_ids[i].item()
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if 0 <= eid < num_experts:
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pos = offsets_scratch[eid].item()
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offsets_scratch[eid] += 1
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dst_to_src[pos] = i
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src_to_dst[i] = pos
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return src_to_dst, dst_to_src, expert_sizes
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# ===================================================================
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# Step 3: Expand input (gather tokens by expert ordering)
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# ===================================================================
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# Upstream: kernel::ilu::moe_expand_input
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# → infer::moe_expand_input
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def step3_expand_input(
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self,
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hidden_states: torch.Tensor, # (num_tokens, hidden_size)
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dst_to_src: torch.Tensor, # (num_tokens * topk,) int32
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) -> torch.Tensor:
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"""
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Reorder tokens into expert-grouped order for batched GEMM.
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Returns:
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expanded: (num_tokens * topk, hidden_size) same dtype as input
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"""
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if self.dispatch is not None:
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try:
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return self.dispatch.moe_expand_input(
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hidden_states, dst_to_src, self.config.topk)
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except (RuntimeError, AttributeError):
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pass
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# PyTorch fallback
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src_indices = dst_to_src.long()
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# Each entry in dst_to_src is a flat index into the expanded token list.
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# The source token index is flat_idx // topk
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token_indices = src_indices // self.config.topk
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expanded = hidden_states[token_indices]
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return expanded
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# ===================================================================
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# Step 4: Group GEMM 1 — gate_proj + up_proj (w13)
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# ===================================================================
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# Upstream: kernel::ilu::group_gemm
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# → infer::moe_w16a16_group_gemm
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# weight shape: (num_experts_per_rank, intermediate_size * 2, hidden_size)
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# for gated MLP: w1 and w3 fused into one [2*inter, hidden] matrix
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def step4_gemm1(
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self,
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expanded_input: torch.Tensor, # (total_tokens, hidden_size)
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w13: torch.Tensor, # (E_local, inter*2, hidden) or flat
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expert_sizes: torch.Tensor, # (num_experts,) int32
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) -> torch.Tensor:
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"""
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Group GEMM: expanded_input × w13^T for each expert group.
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Returns:
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gemm1_out: (total_tokens, intermediate_size * 2)
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"""
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if self.dispatch is not None:
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try:
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inter2 = w13.shape[1] if w13.dim() == 3 else w13.shape[0]
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return self.dispatch.moe_group_gemm(
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expanded_input, w13, expert_sizes, inter2)
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except (RuntimeError, AttributeError):
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pass
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# PyTorch fallback: loop over experts
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total_tokens = expanded_input.shape[0]
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out_dim = w13.shape[1] if w13.dim() == 3 else w13.shape[0]
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output = torch.empty(
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total_tokens, out_dim,
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dtype=expanded_input.dtype, device=expanded_input.device)
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offset = 0
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for e in range(expert_sizes.shape[0]):
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count = expert_sizes[e].item()
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if count > 0:
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local_e = e - self.config.start_expert_id
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if 0 <= local_e < w13.shape[0]:
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x_e = expanded_input[offset:offset + count]
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w_e = w13[local_e] # (inter*2, hidden)
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# matmul: (count, hidden) × (hidden, inter*2) = (count, inter*2)
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output[offset:offset + count] = x_e @ w_e.t()
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offset += count
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return output
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# ===================================================================
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# Step 5: Activation — SiLU-and-mul for gated MLP
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# ===================================================================
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# Upstream: kernel::ilu::act_and_mul → infer::silu_and_mul
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# Input: (total_tokens, intermediate_size * 2)
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# Output: (total_tokens, intermediate_size)
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# Split input in half: out = silu(input[:, :inter]) * input[:, inter:]
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def step5_activation(
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self,
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gemm1_out: torch.Tensor, # (total_tokens, inter*2)
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) -> torch.Tensor:
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"""
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Gated SiLU activation.
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Returns:
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act_out: (total_tokens, intermediate_size)
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"""
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if self.config.is_gated:
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half_dim = gemm1_out.shape[-1] // 2
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gate = gemm1_out[:, :half_dim]
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up = gemm1_out[:, half_dim:]
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if self.dispatch is not None:
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try:
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# ixformer expects concatenated input, produces half-width output
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return self.dispatch.silu_and_mul(gemm1_out)
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except (RuntimeError, AttributeError):
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pass
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# PyTorch fallback — explicit silu_and_mul
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return torch.nn.functional.silu(gate) * up
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else:
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if self.config.hidden_act == "silu":
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return torch.nn.functional.silu(gemm1_out)
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elif self.config.hidden_act == "gelu":
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return torch.nn.functional.gelu(gemm1_out)
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else:
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return gemm1_out
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# ===================================================================
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# Step 6: Group GEMM 2 — down_proj (w2)
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# ===================================================================
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# Upstream: kernel::ilu::group_gemm (same as Step 4, different weights)
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# weight shape: (num_experts_per_rank, hidden_size, intermediate_size)
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def step6_gemm2(
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self,
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act_out: torch.Tensor, # (total_tokens, intermediate_size)
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w2: torch.Tensor, # (E_local, hidden, inter)
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expert_sizes: torch.Tensor, # (num_experts,) int32
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) -> torch.Tensor:
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"""
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Group GEMM: act_out × w2^T for each expert group.
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Returns:
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gemm2_out: (total_tokens, hidden_size)
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"""
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if self.dispatch is not None:
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try:
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return self.dispatch.moe_group_gemm(
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act_out, w2, expert_sizes, self.config.hidden_size)
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except (RuntimeError, AttributeError):
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pass
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# PyTorch fallback: loop over experts
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total_tokens = act_out.shape[0]
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output = torch.empty(
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total_tokens, self.config.hidden_size,
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dtype=act_out.dtype, device=act_out.device)
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offset = 0
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for e in range(expert_sizes.shape[0]):
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count = expert_sizes[e].item()
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if count > 0:
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local_e = e - self.config.start_expert_id
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if 0 <= local_e < w2.shape[0]:
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x_e = act_out[offset:offset + count]
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w_e = w2[local_e] # (hidden, inter)
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output[offset:offset + count] = x_e @ w_e.t()
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offset += count
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return output
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# ===================================================================
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# Step 7: Combine — weighted reduce over topk experts
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# ===================================================================
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# Upstream: kernel::ilu::moe_combine_result
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# → infer::moe_output_reduce_sum
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# → cuda::moe_combine_kernel
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# Reorder from expert-sorted back to token order, weighted sum.
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def step7_combine(
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self,
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gemm2_out: torch.Tensor, # (total_tokens, hidden_size) sorted
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topk_weights: torch.Tensor, # (num_tokens, topk) float32
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src_to_dst: torch.Tensor, # (total_tokens,) int32
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) -> torch.Tensor:
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"""
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Weighted combine of expert outputs back to token order.
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Returns:
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final: (num_tokens, hidden_size)
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"""
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num_tokens = topk_weights.shape[0]
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topk = self.config.topk
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hidden_size = gemm2_out.shape[-1]
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if self.dispatch is not None:
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try:
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return self.dispatch.moe_output_reduce_sum(
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gemm2_out, topk_weights, 1.0)
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except (RuntimeError, AttributeError):
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pass
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# PyTorch fallback — matches cuda::moe_combine_kernel logic
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output = torch.zeros(
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num_tokens, hidden_size,
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dtype=gemm2_out.dtype, device=gemm2_out.device)
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for t in range(num_tokens):
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for k in range(topk):
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flat_idx = t * topk + k
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dst_pos = src_to_dst[flat_idx].long().item()
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w = topk_weights[t, k].item()
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output[t] += w * gemm2_out[dst_pos].float()
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return output.to(gemm2_out.dtype)
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# ===================================================================
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# Full forward — orchestrates all 7 steps
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# ===================================================================
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# Upstream: FusedMoEImpl::forward_experts (main orchestrator)
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def forward(
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self,
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hidden_states: torch.Tensor, # (num_tokens, hidden_size)
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router_logits: torch.Tensor, # (num_tokens, num_experts)
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w13: torch.Tensor, # (E_local, inter*2, hidden)
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w2: torch.Tensor, # (E_local, hidden, inter)
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shared_expert_output: Optional[torch.Tensor] = None,
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) -> torch.Tensor:
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"""
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Full MoE forward pass.
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Tensor lifetime management matches xllm:
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- expand_hidden_states is released after step6
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- act_out is released after step6
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- gemm1_out can be released after step5
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"""
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# Step 1: Router
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topk_weights, topk_ids = self.step1_topk_route(router_logits)
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# Step 2: Generate permutation indices
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src_to_dst, dst_to_src, expert_sizes = self.step2_gen_idx(topk_ids)
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# Step 3: Expand input tokens into expert-sorted order
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expand_hidden_states = self.step3_expand_input(
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hidden_states, dst_to_src)
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# Step 4: Group GEMM 1 (gate_proj + up_proj)
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gemm1_out = self.step4_gemm1(
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expand_hidden_states, w13, expert_sizes)
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# Step 5: Activation (gated SiLU)
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act_out = self.step5_activation(gemm1_out)
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del gemm1_out # release intermediate
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# Step 6: Group GEMM 2 (down_proj)
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gemm2_out = self.step6_gemm2(act_out, w2, expert_sizes)
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del expand_hidden_states, act_out # release intermediates
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# Step 7: Weighted combine
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final_hidden_states = self.step7_combine(
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gemm2_out, topk_weights, src_to_dst)
|
||
|
||
# Add shared expert output if present (Qwen3.5 has shared experts)
|
||
if shared_expert_output is not None:
|
||
final_hidden_states = final_hidden_states + shared_expert_output
|
||
|
||
return final_hidden_states
|