add weight transpose check. (#2756)

### What this PR does / why we need it?
In reinforcement learning scenarios, weight updates are required, but
the current inference applies a transpose operation to the weights,
altering their shape. This causes a shape mismatch with the training
weights, triggering an error during weight updates.

### Does this PR introduce _any_ user-facing change?

### How was this patch tested?


- vLLM version: v0.10.1.1
- vLLM main:
6fb2788163

Signed-off-by: wangxiaoxin-sherie <wangxiaoxin7@huawei.com>
Co-authored-by: wangxiaoxin-sherie <wangxiaoxin7@huawei.com>

tests/ut/ops/test_common_fused_moe.py

@@ -17,7 +17,7 @@ from unittest.mock import patch
 import torch
 
 from tests.ut.base import TestBase
-from vllm_ascend.ops.common_fused_moe import fused_experts_moge
+from vllm_ascend.ops.common_fused_moe import AscendFusedMoE, fused_experts_moge
 
 
 class TestFusedExpertsMoGE(TestBase):
@@ -67,3 +67,39 @@ class TestFusedExpertsMoGE(TestBase):
             )
 
             self.assertEqual(output.shape, (4, 128))
+
+
+class TestLoadWeight(TestBase):
+
+    def test_load_w13_transpose(self):
+        with patch.object(AscendFusedMoE, "__init__",
+                          lambda self, *args, **kwargs: None):
+            moe = AscendFusedMoE(num_experts=4, top_k=2, hidden_size=8)
+            moe.hidden_size = 8
+            expert_data = torch.randn(128, 8)
+            loaded_weight = torch.randn(128, 4)
+            moe._load_w13(expert_data, 1, "w1", loaded_weight, 0)
+
+            expert_data = torch.randn(8, 128)
+            loaded_weight = torch.randn(128, 4)
+            moe._load_w13(expert_data, 1, "w1", loaded_weight, 0)
+
+            expert_data = torch.randn(128, 8)
+            loaded_weight = torch.randn(128, 4)
+            moe._load_w13(expert_data, 1, "w3", loaded_weight, 0)
+
+            expert_data = torch.randn(8, 128)
+            loaded_weight = torch.randn(128, 4)
+            moe._load_w13(expert_data, 1, "w3", loaded_weight, 0)
+
+    def test_load_w2_transpose(self):
+        with patch.object(AscendFusedMoE, "__init__",
+                          lambda self, *args, **kwargs: None):
+            moe = AscendFusedMoE(num_experts=4, top_k=2, hidden_size=8)
+            expert_data = torch.randn(128, 4)
+            loaded_weight = torch.randn(128, 8)
+            moe._load_w2(expert_data, 1, loaded_weight, 0)
+
+            expert_data = torch.randn(4, 128)
+            loaded_weight = torch.randn(128, 8)
+            moe._load_w2(expert_data, 1, loaded_weight, 0)

vllm_ascend/ops/common_fused_moe.py

@@ -134,6 +134,7 @@ def unquantized_fused_moe_init_func(self, *args, **kwargs):
         self.use_aclgraph = (vllm_config.compilation_config.level
                              == CompilationLevel.PIECEWISE
                              and not vllm_config.model_config.enforce_eager)
+    self.transpose = True
 
 
 def forward_oot_v01011(
@@ -261,6 +262,7 @@ def forward_oot(
 
 def process_weights_after_loading(self, layer):
     super(UnquantizedFusedMoEMethod, self).process_weights_after_loading(layer)
+    if self.transpose:
         w13_data = self._maybe_pad_weight(layer.w13_weight.data).transpose(
             1, 2).contiguous()
         layer.w13_weight = torch.nn.Parameter(w13_data, requires_grad=False)
@@ -269,6 +271,14 @@ def process_weights_after_loading(self, layer):
             1, 2).contiguous()
         layer.w2_weight = torch.nn.Parameter(w2_data, requires_grad=False)
 
+        self.transpose = False
+    else:
+        w13_data = self._maybe_pad_weight(layer.w13_weight.data)
+        layer.w13_weight = torch.nn.Parameter(w13_data, requires_grad=False)
+
+        w2_data = self._maybe_pad_weight(layer.w2_weight.data)
+        layer.w2_weight = torch.nn.Parameter(w2_data, requires_grad=False)
+
     if not is_310p():
         layer.w13_weight.data = torch_npu.npu_format_cast(
             layer.w13_weight.data, ACL_FORMAT_FRACTAL_NZ)
@@ -358,12 +368,11 @@ class AscendFusedMoE(FusedMoE):
                 num_redundant_experts,
                 has_bias,
             )
-
         setup_token_dispatchers(self.moe_config.ep_size,
                                 top_k=self.top_k,
                                 num_experts=self.global_num_experts,
                                 num_local_experts=self.local_num_experts)
-
+        self.hidden_size = hidden_size
         self.moe_config.tp_group = get_tp_group()
         self.moe_config.dp_group = get_dp_group()
         self.moe_config.ep_group = get_ep_group()
@@ -430,6 +439,61 @@ class AscendFusedMoE(FusedMoE):
 
         return final_hidden_states
 
+    def transpose_weight(self, loaded_weight, expert_data, shard_dim):
+        # Ensure training and inference weight shapes match during RL weight updates
+        if (
+            loaded_weight.shape[1] != expert_data.shape[1] and \
+            loaded_weight.shape[0] != expert_data.shape[0]
+        ):
+            shard_dim = int(not shard_dim)
+            loaded_weight = loaded_weight.transpose(0, 1).contiguous()
+        return loaded_weight, shard_dim
+
+    def _load_w13(self,
+                  expert_data: torch.Tensor,
+                  shard_dim: int,
+                  shard_id: str,
+                  loaded_weight: torch.Tensor,
+                  tp_rank: int,
+                  load_full: bool = False):
+        # Index the loaded weight for tp sharding.
+        # gate_up_proj: "MergedColumnParallel", so tp sharding on output_dim
+        loaded_weight, shard_dim = self.transpose_weight(
+            loaded_weight, expert_data, shard_dim)
+        shard_size = expert_data.shape[shard_dim] // 2
+        if not load_full:
+            loaded_weight = loaded_weight.narrow(shard_dim,
+                                                 shard_size * tp_rank,
+                                                 shard_size)
+        # Narrow parameter and load.
+        # w1, gate_proj: Load into first logical weight of w13.
+        if shard_id == "w1":
+            expert_data = expert_data.narrow(shard_dim, 0, shard_size)
+        # w3, up_proj: Load into second logical weight of w13.
+        else:
+            assert shard_id == "w3"
+            expert_data = expert_data.narrow(shard_dim, shard_size, shard_size)
+        expert_data.copy_(loaded_weight)
+
+    def _load_w2(self,
+                 expert_data: torch.Tensor,
+                 shard_dim: int,
+                 loaded_weight: torch.Tensor,
+                 tp_rank: int,
+                 load_full: bool = False):
+        # Index the loaded weight for tp sharding.
+        # down_proj: "RowParallel" so tp sharding on input_dim
+        # Narrow parameter and load.
+        loaded_weight, shard_dim = self.transpose_weight(
+            loaded_weight, expert_data, shard_dim)
+        shard_size = expert_data.shape[shard_dim]
+        if not load_full:
+            loaded_weight = loaded_weight.narrow(shard_dim,
+                                                 shard_size * tp_rank,
+                                                 shard_size)
+        # w2, down_proj: Load into only logical weight of w2.
+        expert_data.copy_(loaded_weight)
+
 
 class AscendSharedFusedMoE(AscendFusedMoE):