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ColossalAI/colossalai/gemini/stateful_tensor_mgr.py

88 lines
3.8 KiB

import functools
import torch
import types
from colossalai.utils.cuda import get_current_device
from colossalai.zero.sharded_param.sharded_param import ShardedParamV2
from colossalai.zero.sharded_param.tensorful_state import StatefulTensor, TensorState
from colossalai.zero.sharded_param.tensor_utils import colo_model_data_tensor_move_inline, colo_tensor_mem_usage
from colossalai.gemini.tensor_placement_policy import TensorPlacementPolicy
from typing import List
from colossalai.logging import get_dist_logger
class StatefulTensorMgr(object):
"""
Stateful Tensor Manager, inspired from PatrickStar
PatrickStar: Parallel Training of Pre-trained Models via Chunk-based Memory Management
https://arxiv.org/abs/2108.05818
"""
def __init__(self, tensor_placement_policy: TensorPlacementPolicy) -> None:
self._tensor_placement_policy: TensorPlacementPolicy = tensor_placement_policy
self._stateful_tensor_list: List[StatefulTensor] = []
self._logger = get_dist_logger("StatefulTensorMgr")
self._warmup = True
self._compute_list: List[StatefulTensor] = []
self._compute_idx: int = -1
self._cpu_gpu_move_volume = 0
def register_stateful_param(self, param: ShardedParamV2) -> None:
assert isinstance(param, ShardedParamV2)
for t in param.get_payload_tensors():
assert isinstance(t, StatefulTensor)
self._stateful_tensor_list.append(t)
t.trans_state = types.MethodType(functools.partial(self._trans_state, t.trans_state), t)
def adjust_layout(self) -> None:
""" Adjust the layout of statefuil tensor according to the information provided
by mem_stats_collector, which should belongs to a Sharded Model.
"""
# find stateful tensor in state COMPUTE
cuda_demand = 0
move_to_cuda_tensor_list = []
hold_cuda_tensor_list = []
for tensor in self._stateful_tensor_list:
if tensor.state == TensorState.FREE:
continue
if tensor.device.type == 'cuda':
if tensor.state in [TensorState.HOLD, TensorState.HOLD_AFTER_BWD, TensorState.HOLD_AFTER_FWD]:
hold_cuda_tensor_list.append(tensor)
elif tensor.device.type == 'cpu':
if tensor.state == TensorState.COMPUTE:
move_to_cuda_tensor_list.append(tensor)
cuda_demand += colo_tensor_mem_usage(tensor.payload)[1]
else:
raise RuntimeError
self._cpu_gpu_move_volume += self._tensor_placement_policy.evict_tensors(hold_cuda_tensor_list,
cuda_demand=cuda_demand,
warmup=self._warmup,
compute_list=self._compute_list,
compute_idx=self._compute_idx)
# move COMPUTE tensors to CUDA
for t in move_to_cuda_tensor_list:
colo_model_data_tensor_move_inline(t, get_current_device())
self._cpu_gpu_move_volume += t.payload.numel() * t.payload.element_size()
@property
def cpu_gpu_move_volume(self):
return self._cpu_gpu_move_volume
def reset(self):
"""This function must be called when each iteration finishes
"""
self._warmup = False
self._compute_idx = -1
self._cpu_gpu_move_volume = 0
def _trans_state(self, trans_state_func, stateful_tensor, state):
trans_state_func(state)
if state == TensorState.COMPUTE:
self._compute_idx += 1
if self._warmup:
self._compute_list.append(stateful_tensor)