ColossalAI/colossalai/zero/utils/zero_hook.py

115 lines
4.3 KiB
Python

from typing import Optional
import torch
import torch.distributed as dist
from colossalai.registry import OPHOOKS
from colossalai.utils import get_current_device
from colossalai.utils.memory_tracer.memstats_collector import MemStatsCollector
from colossalai.zero.shard_utils import BaseShardStrategy
from colossalai.zero.sharded_param.tensorful_state import TensorState
from colossalai.gemini.stateful_tensor_mgr import StatefulTensorMgr
from colossalai.engine.ophooks import BaseOpHook
@OPHOOKS.register_module
class ZeroHook(BaseOpHook):
"""
A hook to process sharded param for ZeRO method.
"""
def __init__(self,
shard_strategy: BaseShardStrategy,
memstarts_collector: Optional[MemStatsCollector] = None,
stateful_tensor_mgr: Optional[StatefulTensorMgr] = None,
process_group: Optional[dist.ProcessGroup] = None):
super().__init__()
self.shard_strategy = shard_strategy
self.process_group = process_group
# NOTE(jiaruifang) Now the computing device of FWD and BWD is always on GPU
self.computing_device = get_current_device()
self._memstarts_collector = memstarts_collector
self._stateful_tensor_mgr = stateful_tensor_mgr
def gather_parameters(self, module: torch.nn.Module):
# gather sharded parameters
if module.param_is_sharded:
tensor_list = []
for param in module.parameters(recurse=False):
assert hasattr(param, 'colo_attr')
tensor_list.append(param.colo_attr.sharded_data_tensor)
self.shard_strategy.gather(tensor_list, self.process_group)
def shard_parameters(self, module: torch.nn.Module):
# shard gathered parameters
if module.param_is_sharded:
tensor_list = []
for param in module.parameters(recurse=False):
assert hasattr(param, 'colo_attr')
tensor_list.append(param.colo_attr.sharded_data_tensor)
self.shard_strategy.shard(tensor_list, self.process_group)
def adjust_module_data(self, module: torch.nn.Module):
# record overall data statistics
if self._memstarts_collector:
self._memstarts_collector.sample_overall_data()
for param in module.parameters(recurse=False):
param.colo_attr.sharded_data_tensor.trans_state(TensorState.COMPUTE)
# adjust stateful tensor to get enough CUDA memory
self._stateful_tensor_mgr.adjust_layout()
# record model data statistics
if self._memstarts_collector:
self._memstarts_collector.sample_model_data()
def pre_fwd_exec(self, module: torch.nn.Module, *args):
self.adjust_module_data(module)
self.gather_parameters(module)
for param in module.parameters(recurse=False):
param.data = param.colo_attr.data_payload
assert param.data.device.type == 'cuda', f"PRE FWD param.data must be on CUDA"
def post_fwd_exec(self, module: torch.nn.Module, *args):
# change tensor state to HOLD_AFTER_FWD
for param in module.parameters(recurse=False):
param.colo_attr.sharded_data_tensor.trans_state(TensorState.HOLD_AFTER_FWD)
self.shard_parameters(module)
# remove torch payload
for param in module.parameters(recurse=False):
param.colo_attr.set_data_none()
def pre_bwd_exec(self, module: torch.nn.Module, input, output):
self.adjust_module_data(module)
self.gather_parameters(module)
for param in module.parameters(recurse=False):
param.data = param.colo_attr.data_payload
assert param.data.device.type == 'cuda', f"PRE BWD param.data must be on CUDA"
def post_bwd_exec(self, module: torch.nn.Module, input):
# change tensor state to HOLD_AFTER_BWD
for param in module.parameters(recurse=False):
param.colo_attr.sharded_data_tensor.trans_state(TensorState.HOLD_AFTER_BWD)
self.shard_parameters(module)
# remove torch payload
for param in module.parameters(recurse=False):
param.colo_attr.set_data_none()
def pre_iter(self):
pass
def post_iter(self):
if self._stateful_tensor_mgr:
self._stateful_tensor_mgr.reset()