You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
Paddle/python/paddle/fluid/transpiler/memory_optimization_transpi...

399 lines
16 KiB

# Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from collections import defaultdict
from .. import core
from ..framework import Program, default_main_program, Parameter, Variable
from ..backward import _rename_arg_
dtype_to_size = {
core.VarDesc.VarType.FP16: 2,
core.VarDesc.VarType.FP32: 4,
core.VarDesc.VarType.FP64: 8,
core.VarDesc.VarType.INT16: 2,
core.VarDesc.VarType.INT32: 4,
core.VarDesc.VarType.INT64: 8,
core.VarDesc.VarType.BOOL: 1,
core.VarDesc.VarType.UINT8: 1,
}
SUB_BLOCK_OPS = [
"while", "while_grad", "parallel_do", "parallel_do_grad",
"conditional_block", "conditional_block_grad"
]
SUB_BLOCK_PAIR = [("while", "while_grad"), ("parallel_do", "parallel_do_grad"),
("conditional_block", "conditional_block_grad")]
PRINT_LOG = False
class ControlFlowGraph(object):
def __init__(self, program, ops, forward_num, skip_opt):
self._program = program
self._ops = ops
self._forward_num = forward_num
self._successors = defaultdict(set)
self._presuccessors = defaultdict(set)
self._uses = defaultdict(set)
self._defs = defaultdict(set)
self._live_in = defaultdict(set)
self._live_out = defaultdict(set)
self._skip_opt = skip_opt
def _add_connections(self, connections):
"""Populates _successors and _presuccessors for two neighbor nodes."""
for node1, node2 in connections:
self._add(node1, node2)
def _add(self, node1, node2):
self._successors[node1].add(node2)
self._presuccessors[node2].add(node1)
# TODO(panyx0718): We need to have a unified way of building intermediate
# representation.
def _build_graph(self):
"""Build a graph based on op sequence.
"""
self.op_size = len(self._ops)
op_node_connections = [(i, i + 1) for i in range(self.op_size - 1)]
self._add_connections(op_node_connections)
for i in range(self.op_size):
self._uses[i].update(self._ops[i].input_arg_names())
self._defs[i].update(self._ops[i].output_arg_names())
def _update_graph(self, old_name, new_name, begin_idx=0):
for i in range(begin_idx, self.op_size):
if old_name in self._uses[i]:
self._uses[i].remove(old_name)
self._uses[i].add(new_name)
if old_name in self._defs[i]:
self._defs[i].remove(old_name)
self._defs[i].add(new_name)
if old_name in self._live_in[i]:
self._live_in[i].remove(old_name)
self._live_out[i].add(new_name)
if old_name in self._live_out[i]:
self._live_out[i].remove(old_name)
self._live_out[i].add(new_name)
def _reach_fixed_point(self, live_in, live_out):
"""Check if the liveness set has stablized."""
if len(live_in) != len(self._live_in):
return False
if len(live_out) != len(self._live_out):
return False
for i in range(self.op_size):
if (live_in[i] != self._live_in[i] or
live_out[i] != self._live_out[i]):
return False
return True
def _dataflow_analyze(self):
self._build_graph()
live_in = defaultdict(set)
live_out = defaultdict(set)
# Repeatedly apply liveness updates until the algorithm stablize
# on a complete set live input vars and live output vars.
while True:
for i in reversed(range(self.op_size)):
live_in[i] = set(self._live_in[i])
live_out[i] = set(self._live_out[i])
for s in self._successors[i]:
self._live_out[i] |= self._live_in[s]
self._live_in[i] = self._uses[i] | (
self._live_out[i] - self._defs[i])
if self._reach_fixed_point(live_in, live_out):
break
def _get_diff(self, a, b):
u = a & b
return a - u, b - u
def _has_var(self, block_desc, var_name, is_forward):
if is_forward:
return block_desc.has_var(str(var_name))
else:
return block_desc.has_var_recursive(str(var_name))
def _find_var(self, block_desc, var_name, is_forward):
if is_forward:
return block_desc.find_var(str(var_name))
else:
return block_desc.find_var_recursive(str(var_name))
def _check_var_validity(self, block_desc, x, is_forward):
if str(x) == "@EMPTY@":
return False
if not self._has_var(block_desc, x, is_forward):
return False
if self._find_var(block_desc, x, is_forward).persistable():
return False
if self._find_var(block_desc, x,
is_forward).type() != core.VarDesc.VarType.LOD_TENSOR:
return False
if x in self._skip_opt:
return False
if not self._find_var(block_desc, x, is_forward).shape():
return False
return True
# TODO(panyx0718): This needs to be less hacky. It seems memory optimization
# doesn't consider vars copied between cpu and gpu.
def _update_skip_opt_set(self):
for i in range(self.op_size):
op = self._ops[i]
if op.type() == "fill_constant" and op.attr("force_cpu") == True:
self._skip_opt.update(op.output_arg_names())
def release_memory(self, skip_opt_set=None):
self._dataflow_analyze()
self._update_skip_opt_set()
if skip_opt_set:
self._skip_opt.update(skip_opt_set)
fwd_id = 0
bwd_id = 0
for i in range(self.op_size):
op = self._ops[i]
if op.type() in SUB_BLOCK_OPS:
continue
block_desc = op.block()
is_forward = i < self._forward_num
in_diff, out_diff = self._get_diff(self._live_in[i],
self._live_out[i])
can_optimize = filter(
lambda x: self._check_var_validity(block_desc, x, is_forward),
in_diff)
if can_optimize:
index = i + fwd_id + 1 if is_forward else i - self._forward_num + bwd_id + 1
delete_op = block_desc.insert_op(index)
delete_op.set_type("delete_var")
delete_op.set_input("X", can_optimize)
if is_forward:
fwd_id += 1
else:
bwd_id += 1
def memory_optimize(self, skip_opt_set=None, level=0):
def compare_shape(x_shape, cache_shape, opt_level):
if opt_level == 0:
return x_shape == cache_shape
elif opt_level == 1:
if (x_shape[0] == -1) ^ (cache_shape[0] == -1):
return False
x_size = abs(reduce(lambda x, y: x * y, x_shape))
cache_size = abs(reduce(lambda x, y: x * y, cache_shape))
if x_size <= cache_size:
return True
else:
raise ValueError("only support opt_level 0 or 1.")
return False
self._dataflow_analyze()
self._update_skip_opt_set()
# update skip set to meet users' demand
if skip_opt_set:
self._skip_opt.update(skip_opt_set)
self.pool = []
for i in range(self.op_size):
op = self._ops[i]
if op.type() in SUB_BLOCK_OPS:
continue
block_desc = op.block()
is_forward = i < self._forward_num
if self.pool:
defs_can_optimize = filter(
lambda x: self._check_var_validity(block_desc, x, is_forward),
self._defs[i])
out_pair = [
(x, self._find_var(block_desc, x, is_forward).shape())
for x in defs_can_optimize
]
for x, x_shape in out_pair:
# If x is both in uses and defs, it can not be optimized!
if x in self._uses[i]:
continue
for index, cache_pair in enumerate(self.pool):
cache_var = cache_pair[0]
cache_shape = cache_pair[1]
if not compare_shape(x_shape, cache_shape, level):
continue
if not self._has_var(block_desc, cache_var, is_forward):
continue
x_dtype = self._find_var(block_desc, x,
is_forward).dtype()
cache_dtype = self._find_var(block_desc, cache_var,
is_forward).dtype()
# TODO(qijun): actually, we should compare
# dtype_to_size[x_dtype] and dtype_to_size[cache_dtype]
if x_dtype != cache_dtype:
continue
if PRINT_LOG:
print(("Hit Cache !!!! cache pool index "
"is %d, var name is %s, "
"cached var name is %s, "
"var shape is %s ") % (index, x, cache_var,
str(cache_shape)))
self.pool.pop(index)
if x == cache_var:
break
# Rename the var to the cache var already with
# memory allocated in order to reuse the memory.
_rename_arg_(self._ops, x, cache_var, begin_idx=i)
self._program.block(block_desc.id).var(str(
x)).desc = self._find_var(block_desc, cache_var,
is_forward)
self._update_graph(x, cache_var, begin_idx=i)
break
in_diff, _ = self._get_diff(self._live_in[i], self._live_out[i])
can_optimize = filter(
lambda x: self._check_var_validity(block_desc, x, is_forward),
in_diff)
if can_optimize:
for var_name in can_optimize:
self.pool.append((var_name, self._find_var(
block_desc, var_name, is_forward).shape()))
def _process_sub_block_pair(pdesc, sub_block_pair):
"""Creates a list of tuple each of which tracks info of a subblock.
Note: this function doesn't handle nested subblocks yet.
TODO(panyx0718): assert if case nested subblocks happen.
:param pdesc: ProgramDesc.
:param sub_block_pair: A list op pairs. Each op pair is the forward
op and backward op. The ops in the list are special that they contain
a subblock of ops.
:return: A list of tuples, each tuple is (all ops in a subblock pair
including forward and backward, number of forward ops,
all output args names of the ops in the subblock pairs).
"""
ops_list = []
block_desc = pdesc.block(0)
op_size = block_desc.op_size()
for fwd_op, bwd_op in sub_block_pair:
sub_block_ids = []
grad_sub_block_ids = []
sub_block_id_pair = []
sub_op_dict = {}
for i in range(op_size):
op = block_desc.op(i)
if op.type() == fwd_op:
sub_block_ids.append(op.attr("sub_block").id)
sub_op_dict[op.attr("sub_block").id] = op
elif op.type() == bwd_op:
grad_sub_block_ids.append(op.attr("sub_block").id)
sub_op_dict[op.attr("sub_block").id] = op
# Find fwd_op/bwd_op block pair
for grad_id in grad_sub_block_ids:
fwd_id = pdesc.block(grad_id).get_forward_block_idx()
if fwd_id in sub_block_ids:
sub_block_id_pair.append((fwd_id, grad_id))
sub_block_ids.remove(fwd_id)
# Get fwd_op/bwd_op block ops
for fwd_id, grad_id in sub_block_id_pair:
sub_block_ops = []
sub_block = pdesc.block(fwd_id)
block_op_size = sub_block.op_size()
for i in range(block_op_size):
sub_block_ops.append(sub_block.op(i))
grad_sub_block = pdesc.block(grad_id)
grad_sub_block_op_size = grad_sub_block.op_size()
for i in range(grad_sub_block_op_size):
sub_block_ops.append(grad_sub_block.op(i))
sub_op_output = set()
sub_op_output.update(sub_op_dict[fwd_id].output_arg_names())
sub_op_output.update(sub_op_dict[grad_id].output_arg_names())
ops_list.append((sub_block_ops, block_op_size, sub_op_output))
# Process rest fwd_op block ops
for fwd_id in sub_block_ids:
sub_block_ops = []
sub_block = pdesc.block(fwd_id)
sub_block_op_size = sub_block.op_size()
for i in range(sub_block_op_size):
sub_block_ops.append(sub_block.op(i))
sub_op_output = set()
sub_op_output.update(sub_op_dict[fwd_id].output_arg_names())
ops_list.append((sub_block_ops, sub_block_op_size, sub_op_output))
return ops_list
def _get_cfgs(input_program):
"""Process each block and create ControlFlowGraph for each of them.
:param input_program: Program object.
:return: A list of ControlFlowGraph, each corresponds to a block.
"""
ops_list = []
pdesc = input_program.get_desc()
block_desc = pdesc.block(0)
op_size = block_desc.op_size()
# Get global block ops
ops_list.append(
([block_desc.op(i) for i in range(op_size)], op_size, set()))
# Only process one level of nested subblock.
ops_list.extend(_process_sub_block_pair(pdesc, SUB_BLOCK_PAIR))
cfgs = [
ControlFlowGraph(input_program, ops, forward_num, skip_opt)
for ops, forward_num, skip_opt in ops_list
]
return cfgs
def memory_optimize(input_program, skip_opt_set=None, print_log=False, level=0):
"""Optimize memory by reusing var memory.
Note: it doesn't not support subblock nested in subblock.
:param input_program: Input Program
:param print_log: whether to print debug log.
:param level: If level=0, reuse if the shape is completely equal, o
:return:
"""
if level != 0 and level != 1:
raise ValueError("only support opt_level 0 or 1.")
global PRINT_LOG
PRINT_LOG = print_log
cfgs = _get_cfgs(input_program)
for cfg in cfgs:
cfg.memory_optimize(skip_opt_set=skip_opt_set, level=level)
def release_memory(input_program, skip_opt_set=None):
"""
Modify the input program and insert :code:`delete_op` to early drop not used
variables. The modification will be performed inplace.
Notes: This is an experimental API and could be removed in next few
releases. Users should not use this API.
Args:
input_program(Program): The program will be inserted :code:`delete_op`.
"""
cfgs = _get_cfgs(input_program)
for cfg in cfgs:
cfg.release_memory(skip_opt_set=skip_opt_set)