init

vllm/model_executor/model_loader/neuron.py

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+"""Utilities for selecting and loading neuron models."""
+import importlib
+import os
+from typing import Dict, Optional, Tuple
+
+import torch
+import torch.nn as nn
+import transformers
+from transformers import PretrainedConfig
+
+from vllm.config import ModelConfig, ParallelConfig, SchedulerConfig
+from vllm.model_executor.layers.logits_processor import LogitsProcessor
+from vllm.model_executor.layers.sampler import Sampler
+from vllm.model_executor.sampling_metadata import SamplingMetadata
+from vllm.sequence import SamplerOutput
+
+TORCH_DTYPE_TO_NEURON_AMP = {
+    "auto": "f32",
+    "half": "f16",
+    "float16": "f16",
+    "bfloat16": "bf16",
+    "float": "f32",
+    "float32": "f32",
+    torch.float16: "f16",
+    torch.bfloat16: "bf16",
+    torch.float32: "f32",
+}
+
+# Models supported by Neuron.
+_NEURON_SUPPORTED_MODELS: Dict[str, Tuple[str, str, str]] = {
+    "LlamaForCausalLM": ("transformers_neuronx.llama.model",
+                         "LlamaForSampling", "LlamaForCausalLM"),
+    "MistralForCausalLM": ("transformers_neuronx.mistral.model",
+                           "MistralForSampling", "MistralForCausalLM")
+}
+
+
+class NeuronCasualLM(nn.Module):
+
+    def __init__(
+        self,
+        config: PretrainedConfig,
+    ) -> None:
+        super().__init__()
+        self.config = config
+        self.logits_processor = LogitsProcessor(config.vocab_size,
+                                                logits_as_input=True)
+        self.sampler = Sampler()
+
+        # Lazy initialized
+        self.model: nn.Module
+
+    def forward(
+        self,
+        input_ids: torch.Tensor,
+        positions: torch.Tensor,
+        input_block_ids: torch.Tensor,
+    ) -> torch.Tensor:
+        logits = self.model(input_ids,
+                            cache_ids=positions,
+                            start_ids=input_block_ids)
+        return logits
+
+    def compute_logits(self, hidden_states: torch.Tensor,
+                       sampling_metadata: SamplingMetadata) -> torch.Tensor:
+        logits = self.logits_processor(None, hidden_states, sampling_metadata)
+        return logits
+
+    def sample(
+        self,
+        logits: torch.Tensor,
+        sampling_metadata: SamplingMetadata,
+    ) -> Optional[SamplerOutput]:
+        next_tokens = self.sampler(logits, sampling_metadata)
+        return next_tokens
+
+    def load_weights(self, model_name_or_path: str, **kwargs):
+        arch = _get_model_architecture(self.config)
+        neuronx_module_path, neuronx_model_cls_name, hf_model_cls_name = (
+            _NEURON_SUPPORTED_MODELS[arch])
+        neuronx_module = importlib.import_module(neuronx_module_path)
+        neuronx_model_cls = getattr(neuronx_module, neuronx_model_cls_name)
+
+        split_model_dir = f"{model_name_or_path}-split"
+        if os.path.isdir(os.path.join(model_name_or_path,
+                                      "pytorch_model.bin")):
+            split_model_dir = model_name_or_path
+        elif not os.path.exists(f"{model_name_or_path}-split"):
+            hf_model_cls = getattr(transformers, hf_model_cls_name)
+            from transformers_neuronx.module import save_pretrained_split
+
+            hf_model = hf_model_cls.from_pretrained(model_name_or_path,
+                                                    low_cpu_mem_usage=True)
+            save_pretrained_split(hf_model, f"{model_name_or_path}-split")
+
+        self.model = neuronx_model_cls.from_pretrained(split_model_dir,
+                                                       **kwargs)
+        self.model.to_neuron()
+
+
+def _get_model_architecture(config: PretrainedConfig) -> str:
+    architectures = getattr(config, "architectures", [])
+    for arch in architectures:
+        if arch in _NEURON_SUPPORTED_MODELS:
+            return arch
+    raise ValueError(
+        f"Model architectures {architectures} are not supported on Neuron "
+        f"for now. Supported architectures: "
+        f"{list(_NEURON_SUPPORTED_MODELS.keys())}")
+
+
+def get_neuron_model(model_config: ModelConfig,
+                     parallel_config: ParallelConfig,
+                     scheduler_config: SchedulerConfig) -> nn.Module:
+    from transformers_neuronx.config import (ContinuousBatchingConfig,
+                                             NeuronConfig)
+
+    # Create a model instance.
+    model = NeuronCasualLM(model_config.hf_config)
+
+    continuous_batching_config = ContinuousBatchingConfig(
+        batch_size_for_shared_caches=scheduler_config.max_num_seqs)
+    neuron_config = NeuronConfig(
+        continuous_batching=continuous_batching_config)
+
+    # Load the weights from the cached or downloaded files.
+    model.load_weights(
+        model_config.model,
+        tp_degree=parallel_config.tensor_parallel_size,
+        amp=TORCH_DTYPE_TO_NEURON_AMP[model_config.dtype],
+        neuron_config=neuron_config,
+        context_length_estimate=[scheduler_config.max_model_len],
+        n_positions=[scheduler_config.max_model_len],
+        batch_size=scheduler_config.max_num_seqs)
+
+    return model.eval()