Files
project_6/ex_engine/python/patch_moe_hot_path.py
project_6 49034d1d09 feat: 10-file MoE bridge pipeline — compile, dispatch, patch, test
The complete chain to replace 180 Python fallback calls/token with C++:

BUILD:
  1. moe_ops_impl.cu (489L) — 5 MoE functions in ixformer::infer namespace
     - topk_softmax: dynamic num_experts (128 for Qwen3.5), shared-mem
     - moe_compute_token_index: histogram + prefix_sum + scatter
     - moe_expand_input: gather kernel
     - moe_w16a16_group_gemm: per-expert cuinferCustomGemm loop
     - moe_output_reduce_sum: weighted combine
  2. ix_full_bridge_v2.cpp (461L) — pybind11 bridge, 14+1 functions
  3. build_moe_bridge.sh — torch.utils.cpp_extension compile, link cuinfer+ixformer

DISPATCH:
  4. moe_dispatch.py — 3-tier fallback (fused → individual → PyTorch)
  5. patch_moe_hot_path.py — monkey-patch Qwen3_5MoE.forward()

CONFIG:
  6. computility-run.yaml — max_num_seqs 1→2 (match sub168 baseline)
  7. patch_ops.sh — add build + deploy steps for MoE bridge

VERIFY:
  8. probe_moe_symbols.sh — nm -D .so to confirm 5 MoE symbols present
  9. test_moe_bridge.py — random-tensor integration test (no weights needed)

DEPLOY:
 10. Dockerfile — COPY ex_engine sources for in-container compilation
2026-08-16 17:46:53 +00:00

110 lines
3.9 KiB
Python

"""patch_moe_hot_path.py — Replace Qwen3_5MoE.forward() with bridge dispatch.
This is the key performance patch: replaces the Python expert-loop MoE
with a single C++ call that does all 7 steps fused.
Called by: patch_ops.sh during Docker build
Target: vllm.model_executor.models.qwen3_5.Qwen3_5MoE
Reference: ex_engine/python/patch_vllm_hot_path.py (200L)
"""
import sys
import logging
import torch
logger = logging.getLogger("patch_moe_hot_path")
def apply_moe_patch():
"""Monkey-patch Qwen3_5MoE.forward to use moe_dispatch."""
try:
from ex_engine.python.moe_dispatch import moe_forward, get_tier
except ImportError:
try:
from moe_dispatch import moe_forward, get_tier
except ImportError:
logger.warning("[moe_patch] moe_dispatch not available, skipping patch")
return False
tier = get_tier()
logger.info(f"[moe_patch] moe_dispatch tier={tier}")
# Find the MoE class
moe_cls = None
try:
from vllm.model_executor.models.qwen3_5 import Qwen3_5MoE
moe_cls = Qwen3_5MoE
except ImportError:
pass
if moe_cls is None:
# Try to find it in sys.modules (may be registered under different name)
for mod_name, mod in sys.modules.items():
if hasattr(mod, 'Qwen3_5MoE'):
moe_cls = getattr(mod, 'Qwen3_5MoE')
break
if moe_cls is None:
logger.warning("[moe_patch] Qwen3_5MoE class not found")
return False
# Save original forward
_original_forward = moe_cls.forward
def patched_forward(self, hidden_states, *args, **kwargs):
"""Patched MoE forward using bridge dispatch."""
# Get router logits
# In Qwen3_5, the gate + shared_expert_gate are concatenated:
# router_and_shared_gate = self.gate(hidden_states)
# router_logits = router_and_shared_gate[..., :self.num_experts]
# shared_gate = router_and_shared_gate[..., -1]
router_and_shared_gate = self.gate(hidden_states)
router_logits = router_and_shared_gate[..., :self.num_experts]
# Shared expert (if any) — run in parallel
shared_output = None
if hasattr(self, 'shared_expert') and self.shared_expert is not None:
if hasattr(self, 'shared_expert_gate'):
shared_gate = torch.sigmoid(
router_and_shared_gate[..., -1].unsqueeze(-1))
else:
shared_gate = None
# Routed experts via bridge
try:
routed_output = moe_forward(
hidden_states.view(-1, hidden_states.shape[-1]),
router_logits.view(-1, router_logits.shape[-1]),
self.w13_weight if hasattr(self, 'w13_weight') else self.experts.w13_weight,
self.w2_weight if hasattr(self, 'w2_weight') else self.experts.w2_weight,
topk=self.top_k,
num_experts=self.num_experts,
renormalize=True,
)
routed_output = routed_output.view_as(hidden_states)
except Exception as e:
logger.warning(f"[moe_patch] Bridge failed ({e}), using original forward")
return _original_forward(self, hidden_states, *args, **kwargs)
# Add shared expert output
if hasattr(self, 'shared_expert') and self.shared_expert is not None:
shared_out = self.shared_expert(hidden_states)
if shared_gate is not None:
shared_out = shared_out * shared_gate
routed_output = routed_output + shared_out
return routed_output
# Only patch if we have a real bridge (not pure Python fallback)
if tier < 2:
moe_cls.forward = patched_forward
logger.info(f"[moe_patch] ✓ Patched Qwen3_5MoE.forward (tier={tier})")
return True
else:
logger.info("[moe_patch] Tier 2 (Python only), not patching")
return False
if __name__ == "__main__":
apply_moe_patch()