ColossalAI/colossalai/tensor/param_op_hook.py

149 lines
4.3 KiB
Python

from abc import ABC, abstractmethod
from contextlib import contextmanager
from typing import Any, List, Tuple
import torch
from colossalai.tensor.colo_tensor import ColoTensor
from colossalai.tensor.tensor_spec import ColoTensorSpec
class ParamOpHook(ABC):
"""Hook which is triggered by each operation when operands contain ColoParameter.
To customize it, you must inherit this abstract class, and implement ``pre_forward``,
``post_forward``, ``pre_backward`` and ``post_backward``. These four methods take a list
of ColoParameter.
"""
@abstractmethod
def pre_forward(self, params: List[torch.Tensor]) -> None:
pass
@abstractmethod
def post_forward(self, params: List[torch.Tensor]) -> None:
pass
@abstractmethod
def pre_backward(self, params: List[torch.Tensor]) -> None:
pass
@abstractmethod
def post_backward(self, params: List[torch.Tensor]) -> None:
pass
class ParamOpHookManager:
"""Manage your param op hooks. It only has static methods.
The only static method you should call is ``use_hooks(*hooks)``.
"""
hooks: Tuple[ParamOpHook, ...] = tuple()
@staticmethod
@contextmanager
def use_hooks(*hooks: ParamOpHook):
"""Change the param op hooks you use. Nested calling is allowed.
Example:
>>> with ParamOpHookManager.use_hooks(*hooks):
>>> do_something()
>>> with ParamOpHookManager.use_hooks():
>>> // clear hooks
>>> do_something()
"""
try:
old_param_op_hooks = ParamOpHookManager.hooks
ParamOpHookManager.hooks = hooks
yield
finally:
ParamOpHookManager.hooks = old_param_op_hooks
@staticmethod
def _trigger_pre_forward(params: List[torch.Tensor]) -> None:
for hook in ParamOpHookManager.hooks:
hook.pre_forward(params)
@staticmethod
def _trigger_post_forward(params: List[torch.Tensor]) -> None:
for hook in ParamOpHookManager.hooks:
hook.post_forward(params)
@staticmethod
def _trigger_pre_backward(params: List[torch.Tensor]) -> None:
for hook in ParamOpHookManager.hooks:
hook.pre_backward(params)
@staticmethod
def _trigger_post_backward(params: List[torch.Tensor]) -> None:
for hook in ParamOpHookManager.hooks:
hook.post_backward(params)
@staticmethod
def pre_op(params: List[torch.Tensor], *args: Any) -> list:
ParamOpHookManager._trigger_pre_forward(params)
args_info = _get_colo_tensors_info(*args)
rets = PreFwdPostBwd.apply(params, *args)
return _update_colo_tensors(args_info, *rets)
@staticmethod
def post_op(params: List[torch.Tensor], arg: Any) -> Any:
ParamOpHookManager._trigger_post_forward(params)
arg_info = _get_colo_tensors_info(arg)
ret = PostFwdPreBwd.apply(params, arg)
return _unpack_args(_update_colo_tensors(arg_info, ret))
@staticmethod
def has_hook() -> bool:
return len(ParamOpHookManager.hooks) > 0
class PreFwdPostBwd(torch.autograd.Function):
@staticmethod
def forward(ctx, params, *args):
ctx.params = params
return _unpack_args(args)
@staticmethod
def backward(ctx, *grads):
ParamOpHookManager._trigger_post_backward(ctx.params)
return (None,) + grads
class PostFwdPreBwd(torch.autograd.Function):
@staticmethod
def forward(ctx, params, args):
ctx.params = params
return args
@staticmethod
def backward(ctx, *grads):
ParamOpHookManager._trigger_pre_backward(ctx.params)
return (None,) + grads
def _unpack_args(args):
if len(args) == 1:
return args[0]
return args
def _get_colo_tensors_info(*args) -> list:
info = []
for arg in args:
if isinstance(arg, ColoTensor):
info.append((arg.__class__, ColoTensorSpec(arg.get_process_group(), arg.dist_spec, arg.compute_spec)))
else:
info.append(None)
return info
def _update_colo_tensors(info, *args) -> list:
ret = []
for t_info, arg in zip(info, args):
if t_info is not None:
t_cls, spec = t_info
arg = t_cls.from_torch_tensor(arg, spec=spec)
ret.append(arg)
return ret