[Neuron] [Bugfix] Fix neuron startup (#9374)

Co-authored-by: Jerzy Zagorski <jzagorsk@amazon.com>

vllm/_custom_ops.py

@@ -26,7 +26,8 @@ with contextlib.suppress(ImportError):
     import vllm._moe_C  # noqa: F401
     supports_moe_ops = True
 
-if TYPE_CHECKING:
+# neuron has torch version that doesn't even have impl_abstract
+if TYPE_CHECKING or current_platform.is_neuron():
 
     def register_fake(fn):
         return lambda name: fn

vllm/config.py

@@ -17,8 +17,7 @@ from vllm.transformers_utils.config import (ConfigFormat, get_config,
                                             get_hf_image_processor_config,
                                             get_hf_text_config)
 from vllm.utils import (GiB_bytes, cuda_device_count_stateless, get_cpu_memory,
-                        is_hip, is_neuron, is_openvino, is_xpu,
-                        print_warning_once)
+                        is_hip, is_openvino, is_xpu, print_warning_once)
 
 if TYPE_CHECKING:
     from ray.util.placement_group import PlacementGroup
@@ -215,8 +214,10 @@ class ModelConfig:
         self.is_attention_free = self._init_attention_free()
         self.has_inner_state = self._init_has_inner_state()
 
-        self.override_neuron_config = override_neuron_config if is_neuron(
-        ) else None
+        if current_platform.is_neuron():
+            self.override_neuron_config = override_neuron_config
+        else:
+            self.override_neuron_config = None
 
         supported_tasks, task = self._resolve_task(task, self.hf_config)
         self.supported_tasks = supported_tasks
@@ -368,7 +369,7 @@ class ModelConfig:
                     "Using AWQ quantization with ROCm, but VLLM_USE_TRITON_AWQ"
                     " is not set, enabling VLLM_USE_TRITON_AWQ.")
                 envs.VLLM_USE_TRITON_AWQ = True
-            if is_neuron(
+            if current_platform.is_neuron(
             ) and self.quantization not in neuron_supported_quantization:
                 raise ValueError(
                     f"{self.quantization} quantization is currently not "
@@ -1112,7 +1113,7 @@ class DeviceConfig:
             # Automated device type detection
             if current_platform.is_cuda_alike():
                 self.device_type = "cuda"
-            elif is_neuron():
+            elif current_platform.is_neuron():
                 self.device_type = "neuron"
             elif is_openvino():
                 self.device_type = "openvino"

vllm/platforms/__init__.py

@@ -58,6 +58,13 @@ try:
 except Exception:
     pass
 
+is_neuron = False
+try:
+    import transformers_neuronx  # noqa: F401
+    is_neuron = True
+except ImportError:
+    pass
+
 if is_tpu:
     # people might install pytorch built with cuda but run on tpu
     # so we need to check tpu first
@@ -75,6 +82,9 @@ elif is_xpu:
 elif is_cpu:
     from .cpu import CpuPlatform
     current_platform = CpuPlatform()
+elif is_neuron:
+    from .neuron import NeuronPlatform
+    current_platform = NeuronPlatform()
 else:
     current_platform = UnspecifiedPlatform()
 

vllm/platforms/interface.py

@@ -10,6 +10,7 @@ class PlatformEnum(enum.Enum):
     TPU = enum.auto()
     XPU = enum.auto()
     CPU = enum.auto()
+    NEURON = enum.auto()
     UNSPECIFIED = enum.auto()
 
 
@@ -48,6 +49,9 @@ class Platform:
     def is_cpu(self) -> bool:
         return self._enum == PlatformEnum.CPU
 
+    def is_neuron(self) -> bool:
+        return self._enum == PlatformEnum.NEURON
+
     def is_cuda_alike(self) -> bool:
         """Stateless version of :func:`torch.cuda.is_available`."""
         return self._enum in (PlatformEnum.CUDA, PlatformEnum.ROCM)

vllm/platforms/neuron.py

+from .interface import Platform, PlatformEnum
+
+
+class NeuronPlatform(Platform):
+    _enum = PlatformEnum.NEURON
+
+    @classmethod
+    def get_device_name(cls, device_id: int = 0) -> str:
+        return "neuron"

vllm/triton_utils/importing.py

 from importlib.util import find_spec
 
 from vllm.logger import init_logger
+from vllm.platforms import current_platform
 
 logger = init_logger(__name__)
 
-HAS_TRITON = find_spec("triton") is not None
+# neuron has too old torch
+HAS_TRITON = find_spec(
+    "triton") is not None and not current_platform.is_neuron()
 
 if not HAS_TRITON:
     logger.info("Triton not installed; certain GPU-related functions"

vllm/utils.py

@@ -327,15 +327,6 @@ def is_openvino() -> bool:
         return False
 
 
-@lru_cache(maxsize=None)
-def is_neuron() -> bool:
-    try:
-        import transformers_neuronx
-    except ImportError:
-        transformers_neuronx = None
-    return transformers_neuronx is not None
-
-
 @lru_cache(maxsize=None)
 def is_xpu() -> bool:
     from importlib.metadata import PackageNotFoundError, version
@@ -786,7 +777,7 @@ def is_pin_memory_available() -> bool:
     elif is_xpu():
         print_warning_once("Pin memory is not supported on XPU.")
         return False
-    elif is_neuron():
+    elif current_platform.is_neuron():
         print_warning_once("Pin memory is not supported on Neuron.")
         return False
     elif current_platform.is_cpu() or is_openvino():