ColossalAI/chunk_codegen.py

650 lines
27 KiB
Python

import colossalai
import torch
import copy
from typing import List, Callable, Any, Tuple, Dict, Iterable
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__ = ['ChunkCodeGen']
else:
__all__ = ['python_code_with_activation_checkpoint']
def _gen_chunk_slice_dim(chunk_dim, chunk_idx_name, shape):
new_shape = "["
for idx, i in enumerate(shape):
if idx == chunk_dim:
new_shape += "%s:%s + chunk_size" % (chunk_idx_name, chunk_idx_name)
else:
new_shape += ":"
new_shape += ", "
new_shape = new_shape[:-2] + "]"
return new_shape
def _get_first_non_single_dim(shape):
for idx, i in enumerate(shape):
if i == 1:
continue
else:
return idx
raise RuntimeError("can not get first non single dim for shape", shape)
def _gen_loop_start(chunk_input_meta, chunk_output, chunk_size=2):
if len(chunk_input_meta) == 1:
node = chunk_input_meta[0]
node_shape = node.meta['tensor_meta'].shape
chunk_dim = _get_first_non_single_dim(node_shape)
chunk_slice = _gen_chunk_slice_dim(chunk_dim, "gen_chunk_idx", node_shape)
out_shape = str(list(chunk_output.meta['tensor_meta'].shape))
context = "chunk_result = torch.empty(%s, dtype=%s.dtype, device=%s.device); chunk_size = %d\nfor gen_chunk_idx in range" % (
out_shape, node.name, node.name, chunk_size)
context += "(0, %s.shape[%d], chunk_size):\n" % (node.name, chunk_dim)
context += " chunk_tensor = %s%s\n" % (node.name, chunk_slice)
else:
raise NotImplementedError("input with size %d not implemented" % len(chunk_input_meta))
return context
def _gen_loop_end(chunk_outputs, chunk_inputs, node_list):
chunk_inputs_name = chunk_inputs[0].name
chunk_outputs_name = chunk_outputs.name
chunk_outputs_idx = _find_idx_by_name(chunk_outputs_name, node_list)
chunk_output_shape = chunk_outputs.meta['tensor_meta'].shape
chunk_dim = _get_first_non_single_dim(chunk_output_shape)
chunk_slice = _gen_chunk_slice_dim(chunk_dim, "gen_chunk_idx", chunk_output_shape)
context = " chunk_result%s = %s\n" % (chunk_slice, chunk_outputs_name)
context += chunk_outputs_name + " = chunk_result; chunk_result = None; chunk_size = None"
# determine if its the last use for chunk input
users_name = list(chunk_inputs[0].users.keys())
if all([_find_idx_by_name(user.name, node_list) <= chunk_outputs_idx for user in users_name]):
context += "; %s = None" % chunk_inputs_name
context += "\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(input_node)
# 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(output_node)
return input_nodes, output_nodes
def _find_idx_by_name(name, nodes_list):
for idx, node in enumerate(nodes_list):
if node.name == name:
return idx
raise RuntimeError("name %s not found in node list" % name)
def _find_offload_regions(nodes: List[Node]):
"""This function is to find the offload regions
In pofo algorithm, during annotation, we will annotate the offload region with the
list in the form of [idx, offload_input, offload_bar]. idx indicates the offload
region's index, offload_input is a bool type indicates whether we need to offload
the input, offload_bar is a bool type indicates whether we need to offload all the
intermediate x_bars of this region.
"""
offload_regions = []
offload_labels = []
start = -1
end = -1
current_region = None
for idx, node in enumerate(nodes):
if hasattr(node, 'activation_offload') and isinstance(getattr(node, 'activation_offload', None), Iterable):
act_offload_label = node.activation_offload
if current_region == None:
current_region = act_offload_label
start = idx
offload_labels.append(act_offload_label)
if act_offload_label != current_region:
assert start != -1
offload_regions.append((start, idx - 1))
offload_labels.append(act_offload_label)
current_region = act_offload_label
start = idx
end = -1
else:
if current_region is not None:
end = idx - 1
assert start != -1 and end != -1
offload_regions.append((start, end))
start = end = -1
current_region = None
else:
pass
return offload_regions, offload_labels
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_chunk(body, ckpt_func, nodes, emit_node_func, delete_unused_value_func, meta_nodes):
"""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
"""
# find the offload regions
chunk_regions = [(2, 5)]
chunk_starts = [item[0] for item in chunk_regions]
chunk_ends = [item[1] for item in chunk_regions]
chunk_inputs = []
chunk_outputs = []
within_chunk_region = False
node_list = list(nodes)
# find the input and output var names for each offload region
for idx, (start, end) in enumerate(chunk_regions):
offload_node_list = node_list[start:end + 1]
inputs, outputs = _find_input_and_output_nodes(offload_node_list)
chunk_inputs.append(inputs)
chunk_outputs.append(outputs)
chunk_inputs_idx = [[_find_idx_by_name(j.name, node_list) for j in i] for i in chunk_inputs]
chunk_outputs_idx = [[_find_idx_by_name(j.name, node_list) for j in i] for i in chunk_outputs]
chunk_inputs_names = []
for i in chunk_inputs:
for j in i:
chunk_inputs_names.append(j.name)
# this flag is to prevent repeated insert of save tensors
# hooks definition in ckpt_func
node_idx = 0
region_idx = 0
while node_idx < len(node_list):
node = node_list[node_idx]
if node_idx in chunk_starts:
within_chunk_region = True
# add for loop
chunk_input_meta = [meta_nodes[i] for i in chunk_inputs_idx[region_idx]]
body.append(_gen_loop_start(chunk_input_meta, node_list[chunk_ends[region_idx]]))
if within_chunk_region:
emit_node_func(node, body)
# replace input var with chunk var
if node_idx in chunk_starts:
body[-1] = body[-1].replace("("+ chunk_inputs[region_idx][0].name +")", '(chunk_tensor)')
body[-1] = ' ' + body[-1]
delete_unused_value_func(node, body, chunk_inputs_names)
else:
emit_node_func(node, body)
if node_idx not in chunk_inputs:
delete_unused_value_func(node, body, chunk_inputs_names)
if node_idx in chunk_ends:
body.append(_gen_loop_end(node, chunk_inputs[region_idx], node_list))
within_chunk_region = False
region_idx += 1
node_idx += 1
if CODEGEN_AVAILABLE:
class ChunkCodeGen(CodeGen):
def __init__(self, meta_graph):
super().__init__()
self.meta_node = list(meta_graph.graph.nodes)
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, to_keep=[]):
"""
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, [])
nodes_to_delete = [i for i in nodes_to_delete if i.name not in to_keep]
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
emit_code_with_chunk(body, ckpt_func, nodes, emit_node, delete_unused_values, self.meta_node)
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}"""
print(fn_code)
return PythonCode(fn_code, globals_)