199 lines
9.3 KiB
Python
199 lines
9.3 KiB
Python
import torch
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from nanovllm.config import Config
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from nanovllm.engine.sequence import Sequence
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from nanovllm.utils.context import set_context, get_context, reset_context
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from nanovllm.utils.memory import get_gpu_memory
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from nanovllm.models.qwen3 import Qwen3ForCausalLM
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from nanovllm.layers.sampler import Sampler
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class ModelRunner:
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def __init__(self, config: Config):
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self.config = config
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hf_config = config.hf_config
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self.block_size = config.kvcache_block_size
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self.enforce_eager = config.enforce_eager
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default_dtype = torch.get_default_dtype()
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torch.set_default_dtype(hf_config.torch_dtype)
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torch.set_default_device("cuda")
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self.model = Qwen3ForCausalLM(hf_config)
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self.model.load_weights(config.model)
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self.sampler = Sampler()
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self.allocate_kv_cache(config.gpu_memory_utilization)
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if not self.enforce_eager:
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self.capture_model()
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torch.set_default_device("cpu")
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torch.set_default_dtype(default_dtype)
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def allocate_kv_cache(self, gpu_memory_utilization):
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config = self.config
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hf_config = config.hf_config
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total, used, _ = get_gpu_memory()
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free = total * gpu_memory_utilization - used
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block_bytes = 2 * hf_config.num_hidden_layers * self.block_size * hf_config.num_key_value_heads * hf_config.head_dim * hf_config.torch_dtype.itemsize
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config.num_kvcache_blocks = int(free * 1e6) // block_bytes
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self.kv_cache = torch.zeros(2, hf_config.num_hidden_layers, config.num_kvcache_blocks, self.block_size, hf_config.num_key_value_heads, hf_config.head_dim)
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layer_id = 0
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for module in self.model.modules():
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if hasattr(module, "k_cache") and hasattr(module, "v_cache"):
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module.k_cache = self.kv_cache[0, layer_id]
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module.v_cache = self.kv_cache[1, layer_id]
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layer_id += 1
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def preare_block_tables(self, seqs: list[Sequence]):
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max_len = max(len(seq.block_table) for seq in seqs)
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block_tables = [
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seq.block_table + [-1] * (max_len - len(seq.block_table))
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for seq in seqs
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]
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block_tables = torch.tensor(block_tables, dtype=torch.int32, pin_memory=True).cuda(non_blocking=True)
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return block_tables
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def prepare_prefill(self, seqs: list[Sequence]):
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input_ids = []
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positions = []
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cu_seqlens_q = [0]
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cu_seqlens_k = [0]
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max_seqlen_q = 0
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max_seqlen_k = 0
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slot_mapping = []
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context_lens = None
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block_tables = None
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for seq in seqs:
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seqlen = len(seq)
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input_ids.extend(seq[seq.num_cached_tokens:])
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positions.extend(list(range(seq.num_cached_tokens, len(seq))))
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seqlen_q = seqlen - seq.num_cached_tokens
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seqlen_k = seqlen
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cu_seqlens_q.append(cu_seqlens_q[-1] + seqlen_q)
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cu_seqlens_k.append(cu_seqlens_k[-1] + seqlen_k)
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max_seqlen_q = max(seqlen_q, max_seqlen_q)
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max_seqlen_k = max(seqlen_k, max_seqlen_k)
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for i in range(seq.num_cached_blocks, seq.num_blocks):
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start = seq.block_table[i] * self.block_size
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if i != seq.num_blocks - 1:
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end = start + self.block_size
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else:
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end = start + len(seq.last_block())
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slot_mapping.extend(list(range(start, end)))
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assert len(input_ids) == len(slot_mapping)
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assert len(input_ids) == cu_seqlens_q[-1]
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if cu_seqlens_k[-1] > cu_seqlens_q[-1]: # prefix cache
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context_lens = torch.tensor([len(seq) for seq in seqs], dtype=torch.int32, pin_memory=True).cuda(non_blocking=True)
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block_tables = self.preare_block_tables(seqs)
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input_ids = torch.tensor(input_ids, dtype=torch.int64, pin_memory=True).cuda(non_blocking=True)
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positions = torch.tensor(positions, dtype=torch.int64, pin_memory=True).cuda(non_blocking=True)
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cu_seqlens_q = torch.tensor(cu_seqlens_q, dtype=torch.int32, pin_memory=True).cuda(non_blocking=True)
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cu_seqlens_k = torch.tensor(cu_seqlens_k, dtype=torch.int32, pin_memory=True).cuda(non_blocking=True)
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slot_mapping = torch.tensor(slot_mapping, dtype=torch.int32, pin_memory=True).cuda(non_blocking=True)
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set_context(True, cu_seqlens_q, cu_seqlens_k, max_seqlen_q, max_seqlen_k, slot_mapping, context_lens, block_tables)
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return input_ids, positions
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def prepare_decode(self, seqs: list[Sequence]):
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input_ids = []
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positions = []
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slot_mapping = []
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context_lens = []
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for seq in seqs:
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input_ids.append(seq.last_token)
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positions.append(len(seq))
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context_lens.append(len(seq))
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slot_mapping.append(seq.block_table[-1] * self.block_size + len(seq.last_block()))
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input_ids = torch.tensor(input_ids, dtype=torch.int64, pin_memory=True).cuda(non_blocking=True)
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positions = torch.tensor(positions, dtype=torch.int64, pin_memory=True).cuda(non_blocking=True)
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slot_mapping = torch.tensor(slot_mapping, dtype=torch.int32, pin_memory=True).cuda(non_blocking=True)
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context_lens = torch.tensor(context_lens, dtype=torch.int32, pin_memory=True).cuda(non_blocking=True)
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block_tables = self.preare_block_tables(seqs)
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set_context(False, slot_mapping=slot_mapping, context_lens=context_lens, block_tables=block_tables)
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return input_ids, positions
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def prepare_sample(self, seqs: list[Sequence]):
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temperatures = []
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for seq in seqs:
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temperatures.append(seq.temperature)
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temperatures = torch.tensor(temperatures, dtype=torch.float32, pin_memory=True).cuda(non_blocking=True)
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return temperatures
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@torch.inference_mode()
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def run_model(self, input_ids: torch.Tensor, positions: torch.Tensor, is_prefill):
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if is_prefill or self.enforce_eager or input_ids.size(0) > 256:
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return self.model.compute_logits(self.model(input_ids, positions))
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else:
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bs = input_ids.size(0)
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context = get_context()
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self.reset_graph_vars()
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graph = self.graphs[next(x for x in self.graph_bs if x >= bs)]
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graph_vars = self.graph_vars
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graph_vars["input_ids"][:bs] = input_ids
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graph_vars["positions"][:bs] = positions
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graph_vars["slot_mapping"][:bs] = context.slot_mapping
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graph_vars["context_lens"][:bs] = context.context_lens
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graph_vars["block_tables"][:bs, :context.block_tables.size(1)] = context.block_tables
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graph.replay()
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return self.model.compute_logits(graph_vars["outputs"][:bs])
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def reset_graph_vars(self):
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graph_vars = self.graph_vars
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graph_vars["input_ids"].zero_()
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graph_vars["positions"].zero_()
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graph_vars["slot_mapping"].zero_()
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graph_vars["context_lens"].zero_()
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graph_vars["block_tables"].zero_()
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def run(self, seqs: list[Sequence], is_prefill: bool) -> list[int]:
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input_ids, positions = self.prepare_prefill(seqs) if is_prefill else self.prepare_decode(seqs)
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temperatures = self.prepare_sample(seqs)
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logits = self.run_model(input_ids, positions, is_prefill)
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token_ids = self.sampler(logits, temperatures).tolist()
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reset_context()
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return token_ids
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@torch.inference_mode()
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def capture_model(self):
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get_rng_state = torch.cuda.get_rng_state
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set_rng_state = torch.cuda.set_rng_state
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rng_state = torch.cuda.get_rng_state()
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torch.cuda.get_rng_state = lambda: rng_state
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torch.cuda.set_rng_state = lambda _: None
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config = self.config
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hf_config = config.hf_config
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max_bs = min(self.config.max_num_seqs, 256)
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max_num_blocks = (config.max_model_len + self.block_size - 1) // self.block_size
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input_ids = torch.zeros(max_bs, dtype=torch.int64)
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positions = torch.zeros(max_bs, dtype=torch.int64)
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slot_mapping = torch.zeros(max_bs, dtype=torch.int32)
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context_lens = torch.zeros(max_bs, dtype=torch.int32)
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block_tables = torch.zeros(max_bs, max_num_blocks, dtype=torch.int32)
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outputs = torch.zeros(max_bs, hf_config.hidden_size)
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self.graph_bs = [1, 2, 4, 8, 16] + list(range(32, max_bs + 1, 32))
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self.graphs = {}
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self.graph_pool = None
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for bs in reversed(self.graph_bs):
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graph = torch.cuda.CUDAGraph()
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set_context(False, slot_mapping=slot_mapping[:bs], context_lens=context_lens[:bs], block_tables=block_tables[:bs])
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outputs[:bs] = self.model(input_ids[:bs], positions[:bs]) # warmup
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with torch.cuda.graph(graph, self.graph_pool):
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outputs[:bs] = self.model(input_ids[:bs], positions[:bs]) # capture
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if self.graph_pool is None:
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self.graph_pool = graph.pool()
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self.graphs[bs] = graph
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torch.cuda.synchronize()
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reset_context()
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self.graph_vars = dict(
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input_ids=input_ids,
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positions=positions,
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slot_mapping=slot_mapping,
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context_lens=context_lens,
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block_tables=block_tables,
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outputs=outputs,
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)
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torch.cuda.get_rng_state = get_rng_state
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torch.cuda.set_rng_state = set_rng_state
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