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ColossalAI/colossalai/fx/proxy.py

125 lines
3.6 KiB

import operator
import torch
from torch.fx.proxy import Proxy, Attribute
from typing import List, Union, Any
__all__ = ['ColoProxy']
class ColoProxy(Proxy):
"""
ColoProxy is a proxy class which uses meta tensor to handle data-dependent control flow. The original torch.fx proxy
cannot be used to infer the condition statement, with this proxy, torch.fx can still run even with if statements.
Usage:
proxy = tracer.create_proxy(...)
proxy.meta_data = torch.empty(4, 2, device='meta')
print(len(proxy)) # expect output 4
"""
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
self._meta_data = None
@property
def meta_data(self):
return self._meta_data
@meta_data.setter
def meta_data(self, data: Any):
self._meta_data = data
@property
def has_meta_data(self):
return self._meta_data is not None
def _assert_meta_data_is_tensor(self):
assert torch.is_tensor(
self._meta_data) and self._meta_data.is_meta, f'Meta data is not a meta tensor for {self.node.name}'
def _assert_has_meta_data(self):
assert self._meta_data is not None, f'Meta data is not set for {self.node.name}'
@property
def device(self):
# Hack so we can track when devices are used. During meta-tensor propagation,
# replace these values with a constant 'meta'
return MetaDeviceAttribute(self, "device")
@property
def dtype(self):
self._assert_meta_data_is_tensor()
return self.meta_data.dtype
@property
def shape(self):
self._assert_meta_data_is_tensor()
return self.meta_data.shape
@property
def ndim(self):
return self.dim()
def dim(self):
self._assert_meta_data_is_tensor()
return self.meta_data.dim()
def size(self, dim: int = None):
self._assert_meta_data_is_tensor()
if dim is not None:
return self.meta_data.size(dim=dim)
else:
# size(dim=None) will trigger runtime error for meta tensor
return self.meta_data.size()
def __len__(self):
self._assert_has_meta_data()
return len(self.meta_data)
def __bool__(self):
self._assert_has_meta_data()
return self.meta_data
def __getattr__(self, k):
if k == "meta_data":
return self.__getattribute__(k)
# note: not added to the graph yet, if this is a method call
# we peephole optimize to the method invocation
return Attribute(self, k)
def __setitem__(self, indices, values):
return self.tracer.create_proxy("call_function", operator.setitem, (self, indices, values), {})
def __contains__(self, key):
if self.node.op == "placeholder":
# this is used to handle like
# if x in kwargs
# we don't handle this case for now
return False
return super().__contains__(key)
class ColoAttribute(ColoProxy):
def __init__(self, root, attr: str):
# this class is copied from torch.fx.Attribute
# but inherits ColoProxy
self.root = root
self.attr = attr
self.tracer = root.tracer
self._node = None
@property
def node(self):
if self._node is None:
self._node = self.tracer.create_proxy("call_function", getattr, (self.root, self.attr), {}).node
return self._node
def __call__(self, *args, **kwargs):
return self.tracer.create_proxy("call_method", self.attr, (self.root,) + args, kwargs)
class MetaDeviceAttribute(ColoAttribute):
pass