mirror of https://github.com/hpcaitech/ColossalAI
121 lines
4.1 KiB
Python
121 lines
4.1 KiB
Python
from dataclasses import dataclass
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from typing import Dict, List, Tuple, Union
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import torch
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import torch.distributed as dist
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from colossalai.device.alpha_beta_profiler import AlphaBetaProfiler
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from colossalai.device.device_mesh import DeviceMesh
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@dataclass
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class DeviceMeshInfo:
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"""
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This class is used to store the information used to initialize the device mesh.
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Args:
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physical_ids (List[int]): The physical ids of the current booster. For example, if we have the last 4 GPUs on a 8-devices cluster, then the physical ids should be [4, 5, 6, 7].
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mesh_shapes (List[Union[torch.Size, List[int], Tuple[int]]]): The shape of the mesh. For example, if we have 4 GPUs and we want to use 2D mesh with mesh shape [2, 2], then the mesh shape should be [2, 2].
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"""
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physical_ids: List[int]
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mesh_shape: Union[torch.Size, List[int], Tuple[int]] = None
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def __post_init__(self):
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if self.mesh_shape is not None:
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world_size = len(self.physical_ids)
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mesh_shape_numel = torch.Size(self.mesh_shape).numel()
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assert (
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world_size == mesh_shape_numel
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), f"the numel of mesh_shape should be equal to world size, but got {world_size} != {mesh_shape_numel}"
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def initialize_device_mesh(device_mesh_info: DeviceMeshInfo):
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"""
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This method is used to initialize the device mesh.
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Args:
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device_mesh_info (DeviceMeshInfo): The information used to initialize device mesh.
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"""
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# parse the device mesh info
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physical_devices = device_mesh_info.physical_ids
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physical_mesh = torch.tensor(physical_devices)
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logical_mesh_shape = device_mesh_info.mesh_shape
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if logical_mesh_shape is None:
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ab_profiler = AlphaBetaProfiler(physical_devices)
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# search for the best logical mesh shape
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logical_mesh_id = ab_profiler.search_best_logical_mesh()
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logical_mesh_id = torch.Tensor(logical_mesh_id).to(torch.int)
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else:
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logical_mesh_id = physical_mesh.reshape(logical_mesh_shape)
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device_mesh = DeviceMesh(physical_mesh_id=physical_mesh, logical_mesh_id=logical_mesh_id, init_process_group=True)
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return device_mesh
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class DeviceMeshManager:
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"""
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Device mesh manager is responsible for creating and managing device meshes.
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"""
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def __init__(self):
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self.device_mesh_store: Dict[str, DeviceMesh] = dict()
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def create_device_mesh(self, name, device_mesh_info: DeviceMeshInfo) -> DeviceMesh:
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"""
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Create a device mesh and store it in the manager.
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Args:
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name (str): name of the device mesh
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device_mesh_info (DeviceMeshInfo): the information used to initialize the device mesh
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"""
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if name not in self.device_mesh_store:
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device_mesh = initialize_device_mesh(device_mesh_info)
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self.device_mesh_store[name] = device_mesh
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return device_mesh
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else:
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raise ValueError(f"Device mesh {name} already exists.")
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def get(self, name: str) -> DeviceMesh:
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"""
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Get a device mesh by name.
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Args:
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name (str): name of the device mesh
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Returns:
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DeviceMesh: the device mesh
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"""
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if name in self.device_mesh_store:
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return self.device_mesh_store[name]
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else:
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raise ValueError(f"Device mesh {name} does not exist.")
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def destroy(self, name: str) -> None:
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"""
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Destroy a device mesh by name.
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Args:
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name (str): name of the device mesh
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"""
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if name in self.device_mesh_store:
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for pgs in self.device_mesh_store[name].process_groups_dict.values():
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for pg in pgs:
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dist.destroy_process_group(pg)
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del self.device_mesh_store[name]
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else:
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raise ValueError(f"Device mesh {name} does not exist.")
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def destroy_all(self):
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"""
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Destroy all device meshes.
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"""
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for name in self.device_mesh_store:
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for pgs in self.device_mesh_store[name].process_groups_dict.values():
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for pg in pgs:
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dist.destroy_process_group(pg)
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self.device_mesh_store.clear()
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