269 lines
10 KiB
Python
269 lines
10 KiB
Python
# SPDX-License-Identifier: Apache-2.0
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# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
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"""
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KV cache helper for store.
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"""
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from typing import TYPE_CHECKING, Literal
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import torch
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import vllm.envs as envs
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from vllm import _custom_ops as ops
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from vllm.config import VllmConfig, get_current_vllm_config
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from vllm.distributed.kv_transfer.kv_connector.factory import KVConnectorFactory
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from vllm.logger import init_logger
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from vllm.v1.outputs import KVConnectorOutput, ModelRunnerOutput
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if TYPE_CHECKING:
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from vllm.distributed.kv_transfer.kv_connector.base import KVConnectorBase
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logger = init_logger(__name__)
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class model_aware_kv_ops_helper:
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def __init__(self, config: VllmConfig):
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self.is_deepseek_mla = config.model_config.is_deepseek_mla
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self.use_mla_opt = not envs.VLLM_MLA_DISABLE
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self.tp_size = config.parallel_config.tensor_parallel_size
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def get_model_args(self, model_executable: torch.nn.Module):
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model_config = model_executable.model.config
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self.model_executable = model_executable
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num_heads = int(model_config.num_key_value_heads / self.tp_size)
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hidden_size = model_config.hidden_size
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num_attention_heads = model_config.num_attention_heads
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# Deepseek's MLA (Multi-head Latent Attention) uses two different
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# kv_cache shapes based on whether VLLM_MLA_DISABLE is set to 0.
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# When VLLM_MLA_DISABLE=0 (default), forward absorb is applied,
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# resulting in a kv_cache shape of [num_blks, blk_size, 1,
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# kv_lora_rank + qk_rope_head_dim].
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# When VLLM_MLA_DISABLE=1, standard FA is used instead, leading
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# to a kv_cache shape of [2, num_blks, blk_size,
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# num_key_value_heads / tp, qk_nope_head_dim + qk_rope_head_dim].
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# For more details, see vllm/v1/attention/backends/mla/common.py.
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if self.is_deepseek_mla and self.use_mla_opt:
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head_size = model_config.kv_lora_rank + model_config.qk_rope_head_dim
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num_heads = 1
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elif self.is_deepseek_mla and not self.use_mla_opt:
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head_size = model_config.qk_nope_head_dim + model_config.qk_rope_head_dim
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else:
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head_size = getattr(model_config, "head_dim", None)
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if head_size is None:
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head_size = int(hidden_size // num_attention_heads)
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return num_heads, head_size
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def get_kv_from_cache(self, kv_cache, num_heads, head_size):
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if self.is_deepseek_mla and self.use_mla_opt:
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key_cache = kv_cache.reshape(-1, num_heads, head_size)
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value_cache = kv_cache.reshape(-1, num_heads, head_size)
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else:
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key_cache = kv_cache[0].reshape(-1, num_heads, head_size)
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value_cache = kv_cache[1].reshape(-1, num_heads, head_size)
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return key_cache, value_cache
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def put_kv_to_cache(
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self,
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model_executable: torch.nn.Module,
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keys,
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values,
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layer,
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kv_cache,
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slot_mapping,
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start_pos,
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end_pos,
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):
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model_config = model_executable.model.config
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if self.is_deepseek_mla and self.use_mla_opt:
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layer.self_attn.attn = layer.self_attn.mla_attn
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k_c_normed_k_pe = keys.squeeze(1)
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k_c_normed = k_c_normed_k_pe[:, : model_config.kv_lora_rank]
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k_pe = k_c_normed_k_pe[:, model_config.kv_lora_rank :]
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ops.concat_and_cache_mla(
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k_c_normed.to(kv_cache.device),
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k_pe.to(kv_cache.device),
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kv_cache,
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slot_mapping[start_pos:end_pos],
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layer.self_attn.attn.kv_cache_dtype,
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layer.self_attn.attn._k_scale,
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)
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else:
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key_cache, value_cache = kv_cache[0], kv_cache[1]
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ops.reshape_and_cache_flash(
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keys.to(key_cache.device),
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values.to(value_cache.device),
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key_cache,
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value_cache,
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slot_mapping[start_pos:end_pos],
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layer.self_attn.attn.kv_cache_dtype,
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layer.self_attn.attn._k_scale,
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layer.self_attn.attn._v_scale,
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)
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def get_kv_connector_cache_layout():
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# NOTE (NickLucche) When running disaggregated PD with NIXL, HND layout is
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# used for faster transfer.
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vllm_config = get_current_vllm_config()
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kv_config = vllm_config.kv_transfer_config
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if kv_config is not None:
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connector_cls = KVConnectorFactory.get_connector_class(kv_config)
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required_kvcache_layout = connector_cls.get_required_kvcache_layout(vllm_config)
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if required_kvcache_layout is not None:
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return required_kvcache_layout
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logger.info_once(
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"Connectors do not specify a kv cache layout, defaulting to NHD."
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)
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return "NHD"
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class KVOutputAggregator:
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"""Utility class to aggregate the output of all workers into a single
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output corresponding to Rank 0 for scheduler."""
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def __init__(self, expected_finished_count: int):
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# Complete transfer tracker. Used to track finished requests
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# [req_id -> n_remaining_workers]
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self._recv_remaining_count = dict[str, int]()
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self._send_remaining_count = dict[str, int]()
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self._expected_finished_count = expected_finished_count
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@classmethod
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def from_connector(cls, connector: "KVConnectorBase", world_size: int):
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return cls(connector.get_finished_count() or world_size)
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def aggregate(
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self, outputs: list[ModelRunnerOutput | None], output_rank: int = 0
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) -> ModelRunnerOutput | None:
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if not outputs[output_rank]:
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return None
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# Aggregate kv_connector_output from all workers
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def update_finished_set(
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req_ids: set[str] | None,
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remaining_count_dict: dict[str, int],
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finished_set: set[str],
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) -> None:
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for req_id in req_ids or ():
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remaining_count = remaining_count_dict.get(
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req_id, self._expected_finished_count
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)
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remaining_count_dict[req_id] = remaining_count - 1
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if remaining_count_dict[req_id] == 0:
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finished_set.add(req_id)
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del remaining_count_dict[req_id]
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finished_sending = set[str]()
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finished_recving = set[str]()
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aggregated_kv_connector_stats = None
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invalid_block_ids = set[int]()
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for model_runner_output in outputs:
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assert model_runner_output is not None
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kv_output = model_runner_output.kv_connector_output
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if not kv_output:
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continue
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# Allow the worker to dynamically update the expected number of
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# finished sending/recving for new requests.
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if (
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kv_output.expected_finished_count > 0
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and kv_output.expected_finished_count != self._expected_finished_count
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):
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logger.debug(
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"Expected finished requests updated from %d to %d",
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self._expected_finished_count,
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kv_output.expected_finished_count,
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)
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self._expected_finished_count = kv_output.expected_finished_count
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update_finished_set(
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kv_output.finished_sending, self._send_remaining_count, finished_sending
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)
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update_finished_set(
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kv_output.finished_recving, self._recv_remaining_count, finished_recving
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)
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# Aggregate kv_connector_stats from all workers.
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if aggregated_kv_connector_stats is None:
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# Use the first worker's kv_connector_stats as accumulator.
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aggregated_kv_connector_stats = kv_output.kv_connector_stats
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elif kv_connector_stats := kv_output.kv_connector_stats:
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if aggregated_kv_connector_stats is None:
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aggregated_kv_connector_stats = kv_connector_stats
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else:
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assert isinstance(
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aggregated_kv_connector_stats, type(kv_connector_stats)
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)
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aggregated_kv_connector_stats = (
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aggregated_kv_connector_stats.aggregate(kv_connector_stats)
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)
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invalid_block_ids |= kv_output.invalid_block_ids
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# select output of the worker specified by output_rank
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output = outputs[output_rank]
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assert output is not None
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output.kv_connector_output = KVConnectorOutput(
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finished_sending=finished_sending or None,
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finished_recving=finished_recving or None,
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kv_connector_stats=aggregated_kv_connector_stats or None,
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invalid_block_ids=invalid_block_ids,
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expected_finished_count=self._expected_finished_count,
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)
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return output
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def _make_src_and_dst_indices(
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src_block_ids: list[int],
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dst_block_ids: list[int],
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src_device: torch.device | str,
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dst_device: torch.device | str,
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) -> tuple[torch.Tensor, torch.Tensor]:
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src_indices = torch.tensor(src_block_ids, device=src_device, dtype=torch.int64)
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dst_indices = torch.tensor(dst_block_ids, device=dst_device, dtype=torch.int64)
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return src_indices, dst_indices
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def copy_kv_blocks(
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src_kv_caches: dict[str, torch.Tensor],
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dst_kv_caches: dict[str, torch.Tensor],
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src_block_ids: list[int],
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dst_block_ids: list[int],
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direction: Literal["h2d", "d2h"],
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) -> None:
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"""Copy kv blocks between different buffers."""
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if (
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not src_kv_caches
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or not dst_kv_caches
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or not src_block_ids
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or not dst_block_ids
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or len(src_block_ids) != len(dst_block_ids)
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):
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return
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src_device = next(iter(src_kv_caches.values())).device
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dst_device = next(iter(dst_kv_caches.values())).device
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src_indices, dst_indices = _make_src_and_dst_indices(
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src_block_ids=src_block_ids,
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dst_block_ids=dst_block_ids,
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src_device=src_device,
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dst_device=dst_device,
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)
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from vllm.platforms import current_platform
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if direction == "h2d":
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copy_fn = current_platform.insert_blocks_to_device
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else:
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copy_fn = current_platform.swap_out_blocks_to_host
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for layer_name in src_kv_caches:
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src_tensor = src_kv_caches[layer_name]
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dst_tensor = dst_kv_caches[layer_name]
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copy_fn(src_tensor, dst_tensor, src_indices, dst_indices)
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