ColossalAI/colossalai/fx/passes/algorithms/linearize.py

91 lines
3.0 KiB
Python

from typing import List, Any
from torch.fx import GraphModule, Node
# Common nodes are type of nodes that could be seen as attributes and remain
# unchanged throughout the whole model, it will be used several times by
# different blocks of model, so that it is hard for us to linearize the graph
# when we encounter those kinds of nodes. We let users to annotate some of the
# input as common node, such as attention mask, and the followings are some of
# the ops that could actually be seen as common nodes. With our common node prop,
# we could find some of the "real" common nodes (e.g. the real attention mask
# used in BERT and GPT), the rule is simple, for node who's parents are all common
# nodes or it's op belongs to the following operations, we view this node as a
# newly born common node.
# List of target name that could be seen as common node
COPS = ["getattr", "getitem", "size"]
def _is_cop(target: Any) -> bool:
"""Check if an op could be seen as common node
Args:
target (Any): node target
Returns:
bool
"""
if isinstance(target, str):
return target in COPS
else:
return target.__name__ in COPS
def linearize(gm: GraphModule, cnode: List[str] = None) -> List[List[Node]]:
"""Linearizing the graph
Args:
gm (GraphModule): GraphModule derived by tracing
cnode (List[str], optional): common node List, should be the subset of input. Default to None.
Returns:
List[List[Node]]: List of list, each inside list of Node presents
the actual 'node' in linearized manner.
"""
def _is_sink() -> bool:
"""Check if we can free all dependencies
Returns:
bool
"""
return not sum([v for _, v in deps.items()])
# make sure that item in cnode is valid
if cnode:
for name in cnode:
try:
assert next(node for node in gm.graph.nodes if node.name == name).op == "placeholder", \
f"common node {name} is not an input of the model"
except StopIteration:
raise ValueError(f"common node name {name} not in graph")
else:
cnode = []
deps = {}
linearized_nodes = []
region = []
for n in gm.graph.nodes:
if n.op != "placeholder" and n.op != "output":
for n_par in n._input_nodes:
if n_par.op != "placeholder" and n_par.name not in cnode:
deps[n_par] -= 1
region.append(n)
# if the node could free all dependencies in graph
# we could begin a new node
if _is_sink():
linearized_nodes.append(region)
region = []
# propagate common node attr if possible
if len(n._input_nodes) == len([node for node in n._input_nodes if node.name in cnode]) or _is_cop(n.target):
cnode.append(n.name)
else:
deps[n] = len([user for user in n.users if user.op != "output"])
return linearized_nodes