[Bugfix][CPU] Fallback oneDNN linear to torch linear to fix half gemm support on legecy platforms (#27526)

Signed-off-by: jiang1.li <jiang1.li@intel.com>
Co-authored-by: Isotr0py <mozf@mail2.sysu.edu.cn>

docker/Dockerfile.cpu

@@ -79,7 +79,7 @@ RUN echo 'ulimit -c 0' >> ~/.bashrc
 ######################### BUILD IMAGE #########################
 FROM base AS vllm-build
 
-ARG max_jobs=2
+ARG max_jobs=32
 ENV MAX_JOBS=${max_jobs}
 
 ARG GIT_REPO_CHECK=0

vllm/model_executor/layers/utils.py

@@ -8,9 +8,12 @@ import torch
 
 from vllm import _custom_ops as ops
 from vllm import envs
+from vllm.logger import init_logger
 from vllm.platforms import CpuArchEnum, current_platform
 from vllm.utils.torch_utils import direct_register_custom_op
 
+logger = init_logger(__name__)
+
 
 def shuffle_weight(w: torch.Tensor) -> torch.Tensor:
     # Shuffle weight along the last dimension so that
@@ -178,19 +181,28 @@ def dispatch_cpu_unquantized_gemm(
         )
         if remove_weight:
             layer.weight = torch.nn.Parameter(torch.empty(0), requires_grad=False)
+        return
     elif (
         ops._supports_onednn
         and current_platform.get_cpu_architecture() != CpuArchEnum.POWERPC
     ):
-        origin_weight = layer.weight
-        if remove_weight:
-            layer.weight = torch.nn.Parameter(torch.empty(0), requires_grad=False)
-        handler = ops.create_onednn_mm(origin_weight.t(), 32)
-        layer.cpu_linear = lambda x, weight, bias: ops.onednn_mm(handler, x, bias)
-    else:
-        layer.cpu_linear = lambda x, weight, bias: torch.nn.functional.linear(
-            x, weight, bias
-        )
+        try:
+            origin_weight = layer.weight
+            handler = ops.create_onednn_mm(origin_weight.t(), 32)
+            layer.cpu_linear = lambda x, weight, bias: ops.onednn_mm(handler, x, bias)
+            if remove_weight:
+                layer.weight = torch.nn.Parameter(torch.empty(0), requires_grad=False)
+            return
+        except RuntimeError as e:
+            logger.warning_once(
+                "Failed to create oneDNN linear, fallback to torch linear."
+                f" Exception: {e}"
+            )
+
+    # fallback case
+    layer.cpu_linear = lambda x, weight, bias: torch.nn.functional.linear(
+        x, weight, bias
+    )
 
 
 def cpu_unquantized_gemm(