ColossalAI/colossalai/fx/codegen/activation_checkpoint_codeg...

918 lines
39 KiB
Python

import colossalai
import torch
from typing import List, Callable, Any, Tuple, Dict
try:
from torch.fx.node import Node, Argument, map_arg, _type_repr, _get_qualified_name
from torch.fx.graph import _Namespace, PythonCode, _custom_builtins, _is_from_torch, _format_target, magic_methods, CodeGen, _origin_type_map, inplace_methods, _CustomBuiltin
CODEGEN_AVAILABLE = True
except:
from torch.fx.graph import _Namespace, PythonCode, _custom_builtins, _is_from_torch, _format_target, magic_methods, _origin_type_map, _format_args, _CustomBuiltin
from torch.fx.node import Node, Argument, map_arg, _type_repr, _get_qualified_name
CODEGEN_AVAILABLE = False
if CODEGEN_AVAILABLE:
__all__ = ['ActivationCheckpointCodeGen']
else:
__all__ = ['python_code_with_activation_checkpoint']
def _gen_saved_tensors_hooks():
"""
Generate saved tensors hooks
"""
pack_hook = """def pack_hook(self, x):
if getattr(x, "offload", None):
return (x.device, x.cpu())
else:
return x
"""
unpack_hook = """def unpack_hook(self, packed):
if isinstance(packed, tuple):
device, tensor = packed
return tensor.to(device)
else:
return packed
"""
return pack_hook, unpack_hook
def _gen_save_tensors_hooks_context():
"""
Generate save tensors hooks context
"""
context = "with torch.autograd.graph.saved_tensors_hooks(self.pack_hook, self.unpack_hook):\n"
return context
def _find_input_and_output_nodes(nodes: List[Node]):
"""
Find the input and output node names which are not found in the given list of nodes.
"""
input_nodes = []
output_nodes = []
# if a node has an input node which is not in the node list
# we treat that input node as the input of the checkpoint function
for node in nodes:
for input_node in node._input_nodes.keys():
node_repr = repr(input_node)
if input_node not in nodes and node_repr not in input_nodes:
input_nodes.append(node_repr)
# if a node has a user node which is not in the node list
# we treat that user node as the node receiving the current node output
for node in nodes:
for output_node in node.users.keys():
node_repr = repr(node)
if output_node not in nodes and node_repr not in output_nodes:
output_nodes.append(node_repr)
return input_nodes, output_nodes
def _find_ckpt_regions(nodes: List[Node]):
"""
Find the checkpoint regions given a list of consecutive nodes. The outputs will be list
of tuples, each tuple is in the form of (start_index, end_index).
"""
ckpt_nodes = []
ckpt_regions = []
start = -1
end = -1
current_region = None
for idx, node in enumerate(nodes):
if hasattr(node, 'activation_checkpoint'):
act_ckpt_label = node.activation_checkpoint
# this activation checkpoint label is not set yet
# meaning this is the first node of the activation ckpt region
if current_region is None:
current_region = act_ckpt_label
start = idx
# if activation checkpoint has changed
# we restart the tracking
# e.g. node ckpt states = [ckpt1, ckpt2, ckpt2, ckpt2]
if act_ckpt_label != current_region:
assert start != -1
ckpt_regions.append((start, idx - 1))
current_region = act_ckpt_label
start = idx
end = -1
elif current_region is not None and not hasattr(node, 'activation_checkpoint'):
# used to check the case below
# node ckpt states = [ckpt, ckpt, non-ckpt]
end = idx - 1
assert start != -1 and end != -1
ckpt_regions.append((start, end))
start = end = -1
current_region = None
else:
pass
return ckpt_regions
def _gen_ckpt_fn_def(label, free_vars: List[str]) -> str:
"""
Generate the checkpoint function definition
"""
return f"def checkpoint_{label}({', '.join(['self'] + free_vars)}):"
def _gen_ckpt_output(output_vars: List[str]) -> str:
"""
Generate the return statement for checkpoint region
"""
return f"return {', '.join(output_vars)}"
def _gen_ckpt_usage(label, activation_offload, input_vars, output_vars, use_reentrant=True):
"""
Generate the checkpoint function call code text
"""
outputs = ', '.join(output_vars)
inputs = ', '.join(input_vars)
return f'{outputs} = colossalai.utils.activation_checkpoint.checkpoint(self.checkpoint_{label}, {activation_offload}, {inputs}, use_reentrant={use_reentrant})'
def _end_of_ckpt(node: Node, check_idx: int) -> bool:
"""Check if the node could end the ckpt region
Args:
node (Node): torch.fx.Node
check_idx (int): the index of checkpoint level for
nested checkpoint
Returns:
bool
"""
if hasattr(node, "activation_checkpoint"):
if isinstance(node.activation_checkpoint, list):
return node.activation_checkpoint[check_idx] == None
else:
return False
else:
return True
def _find_nested_ckpt_regions(nodes, check_idx=0):
"""
Find the nested checkpoint regions given a list of consecutive nodes. The outputs
will be list of tuples, each tuple is in the form of (start_index, end_index).
"""
ckpt_regions = []
start = -1
end = -1
current_region = None
for idx, node in enumerate(nodes):
if hasattr(node, 'activation_checkpoint'):
if isinstance(getattr(node, 'activation_checkpoint'), int):
act_ckpt_label = node.activation_checkpoint
else:
act_ckpt_label = node.activation_checkpoint[check_idx]
# this activation checkpoint label is not set yet
# meaning this is the first node of the activation ckpt region
if current_region is None:
current_region = act_ckpt_label
start = idx
# if activation checkpoint has changed
# we restart the tracking
# e.g. node ckpt states = [ckpt1, ckpt2, ckpt2, ckpt2]
if act_ckpt_label != current_region:
assert start != -1
ckpt_regions.append((start, idx - 1))
current_region = act_ckpt_label
start = idx
end = -1
elif current_region is not None and _end_of_ckpt(node, check_idx):
# used to check the case below
# node ckpt states = [ckpt, ckpt, non-ckpt]
end = idx - 1
assert start != -1 and end != -1
ckpt_regions.append((start, end))
start = end = -1
current_region = None
else:
pass
if current_region is not None:
end = len(nodes) - 1
ckpt_regions.append((start, end))
return ckpt_regions
def emit_ckpt_func(body,
ckpt_func,
node_list: List[Node],
emit_node_func,
delete_unused_value_func,
level=0,
in_ckpt=False):
"""Emit ckpt fuction in nested way
Args:
body: forward code, in recursive calls, this part will be checkpoint
functions code
ckpt_func: checkpoint functions code, in recursive calls, this part
will be a buffer
node_list (List[Node]): list of torch.fx.Node
emit_node_func: function to emit a node
delete_unused_value_func: function to delete unused value
level (int, optional): checkpoint level. Defaults to 0.
in_ckpt (bool, optional): indicates wether the func is in recursive
call. Defaults to False.
"""
inputs, outputs = _find_input_and_output_nodes(node_list)
# if the current checkpoint function use int as label, using old generation method
if isinstance(node_list[0].activation_checkpoint, int):
label = node_list[0].activation_checkpoint
ckpt_fn_def = _gen_ckpt_fn_def(label, inputs)
ckpt_func.append(f'{ckpt_fn_def}\n')
for node in node_list:
emit_node_func(node, ckpt_func)
ckpt_func[-1] = ' ' + ckpt_func[-1]
delete_unused_value_func(node, ckpt_func)
ckpt_func.append(' ' + _gen_ckpt_output(outputs) + '\n\n')
activation_offload = getattr(node_list[0], "activation_offload", False)
usage = _gen_ckpt_usage(label, activation_offload, inputs, outputs, False)
usage += "\n"
body.append(usage)
# use nested ckpt function codegen
else:
# label given by each layer, e.g. if you are currently at level [0, 1, 1]
# the label will be '0_1_1'
label = "_".join([str(idx) for idx in node_list[0].activation_checkpoint[:level + 1]])
ckpt_fn_def = _gen_ckpt_fn_def(label, inputs)
ckpt_func.append(f'{ckpt_fn_def}\n')
# if there is more level to fetch
if level + 1 < len(node_list[0].activation_checkpoint):
ckpt_regions = _find_nested_ckpt_regions(node_list, level + 1)
start_idx = [item[0] for item in ckpt_regions]
end_idx = [item[1] for item in ckpt_regions]
# use ckpt_func_buffer to store nested checkpoint functions
ckpt_func_buffer = []
node_idx = 0
while 1:
if node_idx >= len(node_list):
break
if node_idx in start_idx:
ckpt_node_list = node_list[node_idx:end_idx[start_idx.index(node_idx)] + 1]
emit_ckpt_func(ckpt_func, ckpt_func_buffer, ckpt_node_list, emit_node_func,
delete_unused_value_func, level + 1, True)
node_idx += len(ckpt_node_list)
else:
node = node_list[node_idx]
emit_node_func(node, ckpt_func)
ckpt_func[-1] = ' ' + ckpt_func[-1]
delete_unused_value_func(node, ckpt_func)
node_idx += 1
ckpt_func.append(' ' + _gen_ckpt_output(outputs) + '\n\n')
ckpt_func += ckpt_func_buffer
activation_offload = getattr(node_list[0], "activation_offload", False)
usage = _gen_ckpt_usage(label, activation_offload, inputs, outputs, False) + '\n'
if in_ckpt:
usage = ' ' + usage
body.append(usage)
# last level
else:
for node in node_list:
emit_node_func(node, ckpt_func)
ckpt_func[-1] = ' ' + ckpt_func[-1]
delete_unused_value_func(node, ckpt_func)
ckpt_func.append(' ' + _gen_ckpt_output(outputs) + '\n\n')
activation_offload = getattr(node_list[0], "activation_offload", False)
usage = _gen_ckpt_usage(label, activation_offload, inputs, outputs, False) + '\n'
if in_ckpt:
usage = ' ' + usage
body.append(usage)
def emit_code_with_nested_activation_checkpoint(body, ckpt_func, nodes, emit_node_func, delete_unused_value_func):
"""Emit code with nested activation checkpoint
When we detect some of the node.activation_checkpoint is a List, we will use
this function to emit the activation checkpoint codes.
Args:
body: forward code
ckpt_func: checkpoint functions code
nodes: graph.nodes
emit_node_func: function to emit node
delete_unused_value_func: function to remove the unused value
"""
ckpt_regions = _find_nested_ckpt_regions(nodes, 0)
start_idx = [item[0] for item in ckpt_regions]
end_idx = [item[1] for item in ckpt_regions]
node_list = list(nodes)
# this flag is to prevent repeated insert of save tensors
# hooks definition in ckpt_func
is_hook_inserted = False
node_idx = 0
while 1:
# break if we finish the processing all the nodes
if node_idx >= len(node_list):
break
# process ckpt_regions
if node_idx in start_idx:
ckpt_node_list = node_list[node_idx:end_idx[start_idx.index(node_idx)] + 1]
emit_ckpt_func(body, ckpt_func, ckpt_node_list, emit_node_func, delete_unused_value_func)
node_idx += len(ckpt_node_list)
# process node in forward function
else:
node = node_list[node_idx]
# if a node is outside of checkpoint region and want to offload
# it's input activation, we will use torch.saved_tensors_hooks
# to complete the offload process.
if getattr(node, "activation_offload", False):
if not is_hook_inserted:
pack_hook, unpack_hook = _gen_saved_tensors_hooks()
ckpt_func.insert(0, "\n".join([pack_hook, unpack_hook]) + "\n")
for par in node.all_input_nodes:
# annotate the input tensor for pack hook
body.append(f"setattr({repr(par)}, 'offload', True)\n")
body.append(_gen_save_tensors_hooks_context())
emit_node_func(node, body)
body[-1] = ' ' + body[-1]
delete_unused_value_func(node, body)
else:
emit_node_func(node, body)
delete_unused_value_func(node, body)
node_idx += 1
def emit_code_with_activation_checkpoint(body, ckpt_func, nodes, emit_node_func, delete_unused_value_func):
# find the activation checkpoint regions
ckpt_regions = _find_ckpt_regions(nodes)
start_idx = [item[0] for item in ckpt_regions]
end_idx = [item[1] for item in ckpt_regions]
input_vars = []
output_vars = []
within_ckpt_region = False
node_list = list(nodes)
# use this variable to avoid inserting hook functions
# to ckpt_func repeatedly
is_hook_inserted = False
# find the input and output var names for each region
for idx, (start, end) in enumerate(ckpt_regions):
ckpt_node_list = node_list[start:end + 1]
inputs, outputs = _find_input_and_output_nodes(ckpt_node_list)
input_vars.append(inputs)
output_vars.append(outputs)
# append code text to body
for idx, node in enumerate(node_list):
# if this is the first node of the ckpt region
# append the ckpt function defition
if idx in start_idx:
label = start_idx.index(idx)
ckpt_fn_def = _gen_ckpt_fn_def(label, input_vars[label])
ckpt_func.append(f'{ckpt_fn_def}\n')
within_ckpt_region = True
# NOTE: emit_node does not emit a string with newline. It depends
# on delete_unused_values to append one
# NOTE: currently we separate body and ckpt_func definition
if within_ckpt_region:
emit_node_func(node, ckpt_func)
ckpt_func[-1] = ' ' + ckpt_func[-1]
delete_unused_value_func(node, ckpt_func)
else:
# if a node is outside of checkpoint region wants to offload
# it's input activation, we will use torch.saved_tensors_hooks
# to complete the offload process.
if getattr(node, "activation_offload", False):
if not is_hook_inserted:
pack_hook, unpack_hook = _gen_saved_tensors_hooks()
ckpt_func.insert(0, "\n".join([pack_hook, unpack_hook]) + "\n")
for par in node.all_input_nodes:
# annotate the input tensor for pack hook
body.append(f"setattr({repr(par)}, 'offload', True)\n")
body.append(_gen_save_tensors_hooks_context())
emit_node_func(node, body)
body[-1] = ' ' + body[-1]
delete_unused_value_func(node, body)
else:
emit_node_func(node, body)
delete_unused_value_func(node, body)
if idx in end_idx:
# if this is the last node of the ckpt region
# generate return statement
label = end_idx.index(idx)
return_statement = _gen_ckpt_output(output_vars[label])
return_statement = f' {return_statement}\n\n'
ckpt_func.append(return_statement)
# we need to check if the checkpoint need to offload the input
start_node_idx = start_idx[label]
if hasattr(node_list[start_node_idx], 'activation_offload'):
activation_offload = node_list[start_node_idx].activation_offload
else:
activation_offload = False
# we need to check if the checkpoint need use_reentrant=False
use_reentrant = True
non_leaf_input = 0
for var in input_vars[label]:
input_node = next(item for item in node_list if item.name == var)
if input_node.op != "placeholder":
non_leaf_input = 1
for user in input_node.users:
if hasattr(user, "activation_checkpoint"):
if user.activation_checkpoint == label:
if user.op == "call_module":
if hasattr(user.graph.owning_module.get_submodule(user.target), "inplace"):
use_reentrant = not user.graph.owning_module.get_submodule(user.target).inplace
elif user.op == "call_function":
if "inplace" in user.kwargs:
use_reentrant = not user.kwargs["inplace"]
# if all the inputs are leaf nodes, we need to set use_reentrant = False
if not non_leaf_input:
use_reentrant = False
# generate checkpoint function call in a new line
usage = _gen_ckpt_usage(label, activation_offload, input_vars[label], output_vars[label], use_reentrant)
usage += '\n'
body.append(usage)
within_ckpt_region = False
if CODEGEN_AVAILABLE:
class ActivationCheckpointCodeGen(CodeGen):
def _gen_python_code(self, nodes, root_module: str, namespace: _Namespace) -> PythonCode:
free_vars: List[str] = []
body: List[str] = []
globals_: Dict[str, Any] = {}
wrapped_fns: Dict[str, None] = {}
# Wrap string in list to pass by reference
maybe_return_annotation: List[str] = ['']
def add_global(name_hint: str, obj: Any):
"""Add an obj to be tracked as a global.
We call this for names that reference objects external to the
Graph, like functions or types.
Returns: the global name that should be used to reference 'obj' in generated source.
"""
if _is_from_torch(obj) and obj != torch.device: # to support registering torch.device
# HACK: workaround for how torch custom ops are registered. We
# can't import them like normal modules so they must retain their
# fully qualified name.
return _get_qualified_name(obj)
# normalize the name hint to get a proper identifier
global_name = namespace.create_name(name_hint, obj)
if global_name in globals_:
assert globals_[global_name] is obj
return global_name
globals_[global_name] = obj
return global_name
# set _custom_builtins here so that we needn't import colossalai in forward
_custom_builtins["colossalai"] = _CustomBuiltin("import colossalai", colossalai)
# Pre-fill the globals table with registered builtins.
for name, (_, obj) in _custom_builtins.items():
add_global(name, obj)
def type_repr(o: Any):
if o == ():
# Empty tuple is used for empty tuple type annotation Tuple[()]
return '()'
typename = _type_repr(o)
if hasattr(o, '__origin__'):
# This is a generic type, e.g. typing.List[torch.Tensor]
origin_type = _origin_type_map.get(o.__origin__, o.__origin__)
origin_typename = add_global(_type_repr(origin_type), origin_type)
if hasattr(o, '__args__'):
# Assign global names for each of the inner type variables.
args = [type_repr(arg) for arg in o.__args__]
if len(args) == 0:
# Bare type, such as `typing.Tuple` with no subscript
# This code-path used in Python < 3.9
return origin_typename
return f'{origin_typename}[{",".join(args)}]'
else:
# Bare type, such as `typing.Tuple` with no subscript
# This code-path used in Python 3.9+
return origin_typename
# Common case: this is a regular module name like 'foo.bar.baz'
return add_global(typename, o)
def _format_args(args: Tuple[Argument, ...], kwargs: Dict[str, Argument]) -> str:
def _get_repr(arg):
# Handle NamedTuples (if it has `_fields`) via add_global.
if isinstance(arg, tuple) and hasattr(arg, '_fields'):
qualified_name = _get_qualified_name(type(arg))
global_name = add_global(qualified_name, type(arg))
return f"{global_name}{repr(tuple(arg))}"
return repr(arg)
args_s = ', '.join(_get_repr(a) for a in args)
kwargs_s = ', '.join(f'{k} = {_get_repr(v)}' for k, v in kwargs.items())
if args_s and kwargs_s:
return f'{args_s}, {kwargs_s}'
return args_s or kwargs_s
# Run through reverse nodes and record the first instance of a use
# of a given node. This represents the *last* use of the node in the
# execution order of the program, which we will use to free unused
# values
node_to_last_use: Dict[Node, Node] = {}
user_to_last_uses: Dict[Node, List[Node]] = {}
def register_last_uses(n: Node, user: Node):
if n not in node_to_last_use:
node_to_last_use[n] = user
user_to_last_uses.setdefault(user, []).append(n)
for node in reversed(nodes):
map_arg(node.args, lambda n: register_last_uses(n, node))
map_arg(node.kwargs, lambda n: register_last_uses(n, node))
# NOTE: we add a variable to distinguish body and ckpt_func
def delete_unused_values(user: Node, body):
"""
Delete values after their last use. This ensures that values that are
not used in the remainder of the code are freed and the memory usage
of the code is optimal.
"""
if user.op == 'placeholder':
return
if user.op == 'output':
body.append('\n')
return
nodes_to_delete = user_to_last_uses.get(user, [])
if len(nodes_to_delete):
to_delete_str = ' = '.join([repr(n) for n in nodes_to_delete] + ['None'])
body.append(f'; {to_delete_str}\n')
else:
body.append('\n')
# NOTE: we add a variable to distinguish body and ckpt_func
def emit_node(node: Node, body):
maybe_type_annotation = '' if node.type is None else f' : {type_repr(node.type)}'
if node.op == 'placeholder':
assert isinstance(node.target, str)
maybe_default_arg = '' if not node.args else f' = {repr(node.args[0])}'
free_vars.append(f'{node.target}{maybe_type_annotation}{maybe_default_arg}')
raw_name = node.target.replace('*', '')
if raw_name != repr(node):
body.append(f'{repr(node)} = {raw_name}\n')
return
elif node.op == 'call_method':
assert isinstance(node.target, str)
body.append(
f'{repr(node)}{maybe_type_annotation} = {_format_target(repr(node.args[0]), node.target)}'
f'({_format_args(node.args[1:], node.kwargs)})')
return
elif node.op == 'call_function':
assert callable(node.target)
# pretty print operators
if node.target.__module__ == '_operator' and node.target.__name__ in magic_methods:
assert isinstance(node.args, tuple)
body.append(f'{repr(node)}{maybe_type_annotation} = '
f'{magic_methods[node.target.__name__].format(*(repr(a) for a in node.args))}')
return
# pretty print inplace operators; required for jit.script to work properly
# not currently supported in normal FX graphs, but generated by torchdynamo
if node.target.__module__ == '_operator' and node.target.__name__ in inplace_methods:
body.append(f'{inplace_methods[node.target.__name__].format(*(repr(a) for a in node.args))}; '
f'{repr(node)}{maybe_type_annotation} = {repr(node.args[0])}')
return
qualified_name = _get_qualified_name(node.target)
global_name = add_global(qualified_name, node.target)
# special case for getattr: node.args could be 2-argument or 3-argument
# 2-argument: attribute access; 3-argument: fall through to attrib function call with default value
if global_name == 'getattr' and \
isinstance(node.args, tuple) and \
isinstance(node.args[1], str) and \
node.args[1].isidentifier() and \
len(node.args) == 2:
body.append(
f'{repr(node)}{maybe_type_annotation} = {_format_target(repr(node.args[0]), node.args[1])}')
return
body.append(
f'{repr(node)}{maybe_type_annotation} = {global_name}({_format_args(node.args, node.kwargs)})')
if node.meta.get('is_wrapped', False):
wrapped_fns.setdefault(global_name)
return
elif node.op == 'call_module':
assert isinstance(node.target, str)
body.append(f'{repr(node)}{maybe_type_annotation} = '
f'{_format_target(root_module, node.target)}({_format_args(node.args, node.kwargs)})')
return
elif node.op == 'get_attr':
assert isinstance(node.target, str)
body.append(f'{repr(node)}{maybe_type_annotation} = {_format_target(root_module, node.target)}')
return
elif node.op == 'output':
if node.type is not None:
maybe_return_annotation[0] = f" -> {type_repr(node.type)}"
body.append(self.generate_output(node.args[0]))
return
raise NotImplementedError(f'node: {node.op} {node.target}')
# Modified for activation checkpointing
ckpt_func = []
# if any node has a list of labels for activation_checkpoint, we
# will use nested type of activation checkpoint codegen
if any(isinstance(getattr(node, "activation_checkpoint", None), list) for node in nodes):
emit_code_with_nested_activation_checkpoint(body, ckpt_func, nodes, emit_node, delete_unused_values)
else:
emit_code_with_activation_checkpoint(body, ckpt_func, nodes, emit_node, delete_unused_values)
if len(body) == 0:
# If the Graph has no non-placeholder nodes, no lines for the body
# have been emitted. To continue to have valid Python code, emit a
# single pass statement
body.append('pass\n')
if len(wrapped_fns) > 0:
wrap_name = add_global('wrap', torch.fx.wrap)
wrap_stmts = '\n'.join([f'{wrap_name}("{name}")' for name in wrapped_fns])
else:
wrap_stmts = ''
if self._body_transformer:
body = self._body_transformer(body)
for name, value in self.additional_globals():
add_global(name, value)
# as we need colossalai.utils.checkpoint, we need to import colossalai
# in forward function
prologue = self.gen_fn_def(free_vars, maybe_return_annotation[0])
prologue = ''.join(ckpt_func) + prologue
prologue = prologue
code = ''.join(body)
code = '\n'.join(' ' + line for line in code.split('\n'))
fn_code = f"""
{wrap_stmts}
{prologue}
{code}"""
return PythonCode(fn_code, globals_)
else:
def python_code_with_activation_checkpoint(self, root_module: str, namespace: _Namespace) -> PythonCode:
"""
This method is copied from the _python_code of torch.fx.graph.Graph. Modifications are made so that it can generate
code for activation checkpoint.
"""
free_vars: List[str] = []
body: List[str] = []
globals_: Dict[str, Any] = {}
wrapped_fns: Dict[str, None] = {}
# Wrap string in list to pass by reference
maybe_return_annotation: List[str] = ['']
def add_global(name_hint: str, obj: Any):
"""Add an obj to be tracked as a global.
We call this for names that reference objects external to the
Graph, like functions or types.
Returns: the global name that should be used to reference 'obj' in generated source.
"""
if _is_from_torch(obj) and obj != torch.device: # to support registering torch.device
# HACK: workaround for how torch custom ops are registered. We
# can't import them like normal modules so they must retain their
# fully qualified name.
return _get_qualified_name(obj)
# normalize the name hint to get a proper identifier
global_name = namespace.create_name(name_hint, obj)
if global_name in globals_:
assert globals_[global_name] is obj
return global_name
globals_[global_name] = obj
return global_name
# set _custom_builtins here so that we needn't import colossalai in forward
_custom_builtins["colossalai"] = _CustomBuiltin("import colossalai", colossalai)
# Pre-fill the globals table with registered builtins.
for name, (_, obj) in _custom_builtins.items():
add_global(name, obj)
def type_repr(o: Any):
if o == ():
# Empty tuple is used for empty tuple type annotation Tuple[()]
return '()'
typename = _type_repr(o)
# This is a generic type, e.g. typing.List[torch.Tensor]
if hasattr(o, '__origin__'):
origin_type = _origin_type_map.get(o.__origin__, o.__origin__)
origin_typename = add_global(_type_repr(origin_type), origin_type)
# Assign global names for each of the inner type variables.
args = [type_repr(arg) for arg in o.__args__]
return f'{origin_typename}[{",".join(args)}]'
# Common case: this is a regular module name like 'foo.bar.baz'
return add_global(typename, o)
# Run through reverse nodes and record the first instance of a use
# of a given node. This represents the *last* use of the node in the
# execution order of the program, which we will use to free unused
# values
node_to_last_use: Dict[Node, Node] = {}
user_to_last_uses: Dict[Node, List[Node]] = {}
def register_last_uses(n: Node, user: Node):
if n not in node_to_last_use:
node_to_last_use[n] = user
user_to_last_uses.setdefault(user, []).append(n)
for node in reversed(self.nodes):
map_arg(node.args, lambda n: register_last_uses(n, node))
map_arg(node.kwargs, lambda n: register_last_uses(n, node))
# NOTE: we add a variable to distinguish body and ckpt_func
def delete_unused_values(user: Node, body):
"""
Delete values after their last use. This ensures that values that are
not used in the remainder of the code are freed and the memory usage
of the code is optimal.
"""
if user.op == 'placeholder':
return
if user.op == 'output':
body.append('\n')
return
nodes_to_delete = user_to_last_uses.get(user, [])
if len(nodes_to_delete):
to_delete_str = ' = '.join([repr(n) for n in nodes_to_delete] + ['None'])
body.append(f'; {to_delete_str}\n')
else:
body.append('\n')
# NOTE: we add a variable to distinguish body and ckpt_func
def emit_node(node: Node, body):
maybe_type_annotation = '' if node.type is None else f' : {type_repr(node.type)}'
if node.op == 'placeholder':
assert isinstance(node.target, str)
maybe_default_arg = '' if not node.args else f' = {repr(node.args[0])}'
free_vars.append(f'{node.target}{maybe_type_annotation}{maybe_default_arg}')
raw_name = node.target.replace('*', '')
if raw_name != repr(node):
body.append(f'{repr(node)} = {raw_name}\n')
return
elif node.op == 'call_method':
assert isinstance(node.target, str)
body.append(f'{repr(node)}{maybe_type_annotation} = {_format_target(repr(node.args[0]), node.target)}'
f'({_format_args(node.args[1:], node.kwargs)})')
return
elif node.op == 'call_function':
assert callable(node.target)
# pretty print operators
if node.target.__module__ == '_operator' and node.target.__name__ in magic_methods:
assert isinstance(node.args, tuple)
body.append(f'{repr(node)}{maybe_type_annotation} = '
f'{magic_methods[node.target.__name__].format(*(repr(a) for a in node.args))}')
return
qualified_name = _get_qualified_name(node.target)
global_name = add_global(qualified_name, node.target)
# special case for getattr: node.args could be 2-argument or 3-argument
# 2-argument: attribute access; 3-argument: fall through to attrib function call with default value
if global_name == 'getattr' and \
isinstance(node.args, tuple) and \
isinstance(node.args[1], str) and \
node.args[1].isidentifier() and \
len(node.args) == 2:
body.append(
f'{repr(node)}{maybe_type_annotation} = {_format_target(repr(node.args[0]), node.args[1])}')
return
body.append(
f'{repr(node)}{maybe_type_annotation} = {global_name}({_format_args(node.args, node.kwargs)})')
if node.meta.get('is_wrapped', False):
wrapped_fns.setdefault(global_name)
return
elif node.op == 'call_module':
assert isinstance(node.target, str)
body.append(f'{repr(node)}{maybe_type_annotation} = '
f'{_format_target(root_module, node.target)}({_format_args(node.args, node.kwargs)})')
return
elif node.op == 'get_attr':
assert isinstance(node.target, str)
body.append(f'{repr(node)}{maybe_type_annotation} = {_format_target(root_module, node.target)}')
return
elif node.op == 'output':
if node.type is not None:
maybe_return_annotation[0] = f" -> {type_repr(node.type)}"
if self._pytree_info is None:
body.append(f'return {repr(node.args[0])}')
else:
body.append(f'return pytree.tree_unflatten({repr(node.args[0])}, self._out_spec)')
return
raise NotImplementedError(f'node: {node.op} {node.target}')
# Modified for activation checkpointing
ckpt_func = []
# if any node has a list of labels for activation_checkpoint, we
# will use nested type of activation checkpoint codegen
if any(isinstance(getattr(node, "activation_checkpoint", None), list) for node in self.nodes):
emit_code_with_nested_activation_checkpoint(body, ckpt_func, self.nodes, emit_node, delete_unused_values)
else:
emit_code_with_activation_checkpoint(body, ckpt_func, self.nodes, emit_node, delete_unused_values)
if len(body) == 0:
# If the Graph has no non-placeholder nodes, no lines for the body
# have been emitted. To continue to have valid Python code, emit a
# single pass statement
body.append('pass\n')
if self._pytree_info is not None:
orig_args = self._pytree_info.orig_args
has_orig_self = (orig_args[0] == 'self')
if has_orig_self:
free_vars.insert(0, 'self')
if len(free_vars) > 0: # pytree has placeholders in it
body.insert(
0,
f"{', '.join(free_vars)}, = fx_pytree.tree_flatten_spec([{', '.join(orig_args)}], self._in_spec)\n")
else:
orig_args = free_vars
if len(wrapped_fns) > 0:
wrap_name = add_global('wrap', torch.fx.wrap)
wrap_stmts = '\n'.join([f'{wrap_name}("{name}")' for name in wrapped_fns])
else:
wrap_stmts = ''
ckpt_func = ''.join(ckpt_func)
# If the original function didn't have self as its first argument, we
# would have added it.
if len(orig_args) == 0 or orig_args[0] != 'self':
orig_args.insert(0, 'self')
code = ''.join(body)
code = '\n'.join(' ' + line for line in code.split('\n'))
# as we need colossalai.utils.checkpoint, we need to import colossalai
# in forward function
fn_code = f"""
{wrap_stmts}
{ckpt_func}
def forward({', '.join(orig_args)}){maybe_return_annotation[0]}:
{code}"""
return PythonCode(fn_code, globals_)