Files
project_6/ex_engine/python/patch_moe_hot_path.py
2026-08-17 02:16:58 +00:00

109 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()