fix: fp8 quantization failure of qwen 2.5 VL 7B model (#10112)

Signed-off-by: PanJason <pyyjason@gmail.com>

python/sglang/srt/layers/linear.py

@@ -31,6 +31,7 @@ from sglang.srt.layers.parameter import (
     _ColumnvLLMParameter,
 )
 from sglang.srt.layers.quantization.unquant import UnquantizedLinearMethod
+from sglang.srt.layers.utils import pad_or_narrow_weight
 from sglang.srt.utils import is_cpu, is_npu, set_weight_attrs
 
 if TYPE_CHECKING:
@@ -625,6 +626,13 @@ class MergedColumnParallelLinear(ColumnParallelLinear):
                 # bitsandbytes loads the weights of the specific portion
                 # no need to narrow here
                 if not use_bitsandbytes_4bit and not self.use_presharded_weights:
+                    # Padding for special case like qwen2_5_VL's mlp which is not 8-aligned
+                    end_idx = start_idx + shard_size
+                    if end_idx > loaded_weight.shape[output_dim]:
+                        loaded_weight = pad_or_narrow_weight(
+                            loaded_weight, output_dim, start_idx, shard_size
+                        )
+                    else:
                         loaded_weight = loaded_weight.narrow(
                             output_dim, start_idx, shard_size
                         )
@@ -1302,7 +1310,16 @@ class RowParallelLinear(LinearBase):
                     shard_size,
                 )
             else:
-                loaded_weight = loaded_weight.narrow(input_dim, start_idx, shard_size)
+                # Padding for special case like qwen2_5_VL's mlp which is not 8-aligned
+                end_idx = start_idx + shard_size
+                if end_idx > loaded_weight.shape[input_dim]:
+                    loaded_weight = pad_or_narrow_weight(
+                        loaded_weight, input_dim, start_idx, shard_size
+                    )
+                else:
+                    loaded_weight = loaded_weight.narrow(
+                        input_dim, start_idx, shard_size
+                    )
 
         # Special case for loading scales off disk, which often do not
         # have a shape (such as in the case of AutoFP8).

python/sglang/srt/layers/parameter.py

@@ -7,6 +7,7 @@ from typing import Callable, Optional, Union
 import torch
 from torch.nn import Parameter
 
+from sglang.srt.layers.utils import pad_or_narrow_weight
 from sglang.srt.utils import is_cpu
 
 __all__ = [
@@ -156,8 +157,16 @@ class _ColumnvLLMParameter(BasevLLMParameter):
             )
         else:
             if not use_presharded_weights:
+                # Padding for special case like qwen2_5_VL's mlp which is not 8-aligned
+                start_idx = tp_rank * shard_size
+                end_idx = start_idx + shard_size
+                if end_idx > loaded_weight.shape[self.output_dim]:
+                    loaded_weight = pad_or_narrow_weight(
+                        loaded_weight, self.output_dim, start_idx, shard_size
+                    )
+                else:
                     loaded_weight = loaded_weight.narrow(
-                    self.output_dim, tp_rank * shard_size, shard_size
+                        self.output_dim, start_idx, shard_size
                     )
 
         assert param_data.shape == loaded_weight.shape
@@ -257,9 +266,17 @@ class RowvLLMParameter(BasevLLMParameter):
                 param_data.copy_(loaded_weight)
 
                 return
+            else:
+                # Padding for special case like qwen2_5_VL's mlp which is not 8-aligned
+                start_idx = tp_rank * shard_size
+                end_idx = start_idx + shard_size
+                if end_idx > loaded_weight.shape[self.input_dim]:
+                    loaded_weight = pad_or_narrow_weight(
+                        loaded_weight, self.input_dim, start_idx, shard_size
+                    )
                 else:
                     loaded_weight = loaded_weight.narrow(
-                    self.input_dim, tp_rank * shard_size, shard_size
+                        self.input_dim, start_idx, shard_size
                     )
 
         if len(loaded_weight.shape) == 0:

python/sglang/srt/layers/quantization/w8a8_int8.py

@@ -393,13 +393,23 @@ class W8A8Int8LinearMethod(LinearMethodBase):
                 x.dtype,
                 True,  # is_vnni
             )
-
         x_q, x_scale = per_token_quant_int8(x)
 
-        return int8_scaled_mm(
+        x_q_2d = x_q.view(-1, x_q.shape[-1])
-            x_q, layer.weight, x_scale, layer.weight_scale, out_dtype=x.dtype, bias=bias
+        x_scale_2d = x_scale.view(-1, x_scale.shape[-1])
+        output_shape = [*x_q.shape[:-1], layer.weight.shape[1]]
+
+        output = int8_scaled_mm(
+            x_q_2d,
+            layer.weight,
+            x_scale_2d,
+            layer.weight_scale,
+            out_dtype=x.dtype,
+            bias=bias,
         )
 
+        return output.view(output_shape)
+
 
 class W8A8Int8MoEMethod(FusedMoEMethodBase):
     """MoE method for INT8.

python/sglang/srt/layers/utils.py

@@ -15,6 +15,29 @@ def get_layer_id(weight_name):
     return None
 
 
+def pad_or_narrow_weight(
+    loaded_weight: torch.Tensor, input_dim: int, start_idx: int, shard_size: int
+) -> torch.Tensor:
+    # Padding with zeros for special case such as qwen2_5_VL's mlp which is not 8-aligned
+    valid_size = max(loaded_weight.shape[input_dim] - start_idx, 0)
+
+    if valid_size > 0:
+        loaded_slice = loaded_weight.narrow(input_dim, start_idx, valid_size)
+        pad_shape = list(loaded_weight.shape)
+        pad_shape[input_dim] = shard_size - valid_size
+        pad = torch.zeros(
+            pad_shape, dtype=loaded_weight.dtype, device=loaded_weight.device
+        )
+        return torch.cat([loaded_slice, pad], dim=input_dim)
+
+    # All padding
+    pad_shape = list(loaded_weight.shape)
+    pad_shape[input_dim] = shard_size
+    return torch.zeros(
+        pad_shape, dtype=loaded_weight.dtype, device=loaded_weight.device
+    )
+
+
 class PPMissingLayer(torch.nn.Identity):
     # Adapted from
     # https://github.com/vllm-project/vllm/blob/18ed3132d2bfe1df9a74729457b69243955221e8/vllm/model_executor/models/utils.py#L468C1-L486C1

python/sglang/srt/models/qwen2_5_vl.py

@@ -265,7 +265,7 @@ class Qwen2_5_VisionTransformer(nn.Module):
         self.fullatt_block_indexes = vision_config.fullatt_block_indexes
         self.window_size = vision_config.window_size
         self.patch_size = vision_config.patch_size
-        mlp_hidden_size: int = vision_config.intermediate_size
+        mlp_hidden_size: int = ((vision_config.intermediate_size + 7) // 8) * 8
         self.patch_embed = Qwen2_5_VisionPatchEmbed(
             patch_size=patch_size,
             temporal_patch_size=temporal_patch_size,