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.
mindspore/tests/ut/python/parallel/test_grad_accumulation.py

290 lines
11 KiB

# Copyright 2020 Huawei Technologies Co., Ltd
#
# 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.
# ============================================================================
import numpy as np
import mindspore as ms
import mindspore.common.dtype as mstype
from mindspore import context, Tensor, Parameter
from mindspore.nn import Cell, Momentum, Norm
from mindspore.train import Model
from mindspore.ops import operations as P
from mindspore.ops import composite as C
from mindspore.ops import functional as F
from mindspore.common.initializer import initializer
from mindspore.nn.wrap.loss_scale import DynamicLossScaleUpdateCell
from mindspore.context import ParallelMode
from tests.dataset_mock import MindData
class Dataset(MindData):
def __init__(self, predict, label, length=3):
super(Dataset, self).__init__(size=length)
self.predict = predict
self.label = label
self.index = 0
self.length = length
def __iter__(self):
return self
def __next__(self):
if self.index >= self.length:
raise StopIteration
self.index += 1
return self.predict, self.label
def reset(self):
self.index = 0
get_square_sum = C.MultitypeFuncGraph("get_square_sum")
@get_square_sum.register("Tensor")
def _get_square_sum(grad):
norm = P.ReduceSum(False)(F.square(grad), ())
norm = F.expand_dims(F.cast(norm, mstype.float32), 0)
return norm
apply_global_norm = C.MultitypeFuncGraph("apply_global_norm")
@apply_global_norm.register("Tensor", "Tensor", "Tensor")
def _apply_global_norm(clip_norm, global_norm, grad):
grad = grad * clip_norm / global_norm
return grad
class GlobalNorm(Cell):
"""
Calculate the global norm value of given tensors
"""
def __init__(self):
super(GlobalNorm, self).__init__()
self.norm = Norm()
self.hyper_map = C.HyperMap()
def construct(self, grads):
square_sum = self.hyper_map(get_square_sum, grads)
global_norms = F.sqrt(F.addn(square_sum) / F.scalar_to_array(len(square_sum)))
return global_norms
class ClipByGlobalNorm(Cell):
"""
Clip grads by global norm
"""
def __init__(self, clip_norm=1.0):
super(ClipByGlobalNorm, self).__init__()
self.global_norm = GlobalNorm()
self.clip_norm = Tensor([clip_norm], mstype.float32)
self.hyper_map = C.HyperMap()
def construct(self, grads):
global_norm = self.global_norm(grads)
cond = P.GreaterEqual()(global_norm, self.clip_norm)
global_norm = F.select(cond, global_norm, self.clip_norm)
grads = self.hyper_map(F.partial(apply_global_norm, self.clip_norm, global_norm), grads)
return grads
cast = P.Cast()
update_accu_grads = C.MultitypeFuncGraph("update_accu_grads")
@update_accu_grads.register("Tensor", "Tensor")
def _update_accu_grads(accu_grad, grad):
succ = True
return F.depend(succ, F.assign_add(accu_grad, cast(grad, mstype.float32)))
zeroslike = P.ZerosLike()
reset_accu_grads = C.MultitypeFuncGraph("reset_accu_grads")
@reset_accu_grads.register("Tensor")
def _reset_accu_grads(accu_grad):
succ = True
return F.depend(succ, F.assign(accu_grad, zeroslike(accu_grad)))
grad_scale = C.MultitypeFuncGraph("grad_scale")
reciprocal = P.Reciprocal()
@grad_scale.register("Tensor", "Tensor")
def tensor_grad_scale(scale, grad):
return grad * reciprocal(scale)
class TrainAccumulateStepsWithLossScaleCell(Cell):
"""
Encapsulation class of bert network training.
Append an optimizer to the training network after that the construct
function can be called to create the backward graph. To mimic higher batch size, gradients are
accumulated N times before weight update.
Args:
network (Cell): The training network. Note that loss function should have been added.
optimizer (Optimizer): Optimizer for updating the weights.
scale_update_cell (Cell): Cell to do the loss scale. Default: None.
accumulation_steps (int): Number of accumulation steps before gradient update. The global batch size =
batch_size * accumulation_steps. Default: 1.
"""
def __init__(self, network, optimizer, scale_update_cell=None, accumulation_steps=4):
super(TrainAccumulateStepsWithLossScaleCell, self).__init__(auto_prefix=False)
self.network = network
self.network.set_grad()
self.weights = optimizer.parameters
self.optimizer = optimizer
self.accumulation_steps = accumulation_steps
self.one = Tensor(np.array([1]).astype(np.int32))
self.zero = Tensor(np.array([0]).astype(np.int32))
self.local_step = Parameter(initializer(0, [1], mstype.int32), name="local_step")
self.accu_grads = self.weights.clone(prefix="accu_grads", init='zeros')
self.accu_overflow = Parameter(initializer(0, [1], mstype.int32))
self.accu_loss = Parameter(initializer(0, [1], mstype.float32))
self.grad = C.GradOperation(get_by_list=True, sens_param=True)
self.reducer_flag = False
self.parallel_mode = context.get_auto_parallel_context("parallel_mode")
if self.parallel_mode in [ParallelMode.DATA_PARALLEL, ParallelMode.HYBRID_PARALLEL]:
self.reducer_flag = True
self.grad_reducer = F.identity
self.degree = 1
if self.reducer_flag:
self.degree = get_group_size()
self.grad_reducer = DistributedGradReducer(optimizer.parameters, False, self.degree)
self.is_distributed = (self.parallel_mode != ParallelMode.STAND_ALONE)
self.overflow_reducer = F.identity
if self.is_distributed:
self.overflow_reducer = P.AllReduce()
self.cast = P.Cast()
self.alloc_status = P.NPUAllocFloatStatus()
self.get_status = P.NPUGetFloatStatus()
self.clear_before_grad = P.NPUClearFloatStatus()
self.reduce_sum = P.ReduceSum(keep_dims=False)
self.base = Tensor(1, mstype.float32)
self.less_equal = P.LessEqual()
self.logical_or = P.LogicalOr()
self.not_equal = P.NotEqual()
self.select = P.Select()
self.reshape = P.Reshape()
self.hyper_map = C.HyperMap()
self.loss_scale = None
self.loss_scaling_manager = scale_update_cell
if scale_update_cell:
self.loss_scale = Parameter(Tensor(scale_update_cell.get_loss_scale(), dtype=mstype.float32))
@C.add_flags(has_effect=True)
def construct(self, x, b, sens=None):
"""Defines the computation performed."""
weights = self.weights
loss = self.network(x, b)
if sens is None:
scaling_sens = self.loss_scale
else:
scaling_sens = sens
# update accumulation parameters
is_accu_step = self.not_equal(self.local_step, self.accumulation_steps)
self.local_step = self.select(is_accu_step, self.local_step + self.one, self.one)
self.accu_loss = self.select(is_accu_step, self.accu_loss + loss, loss)
mean_loss = self.accu_loss / self.local_step
is_accu_step = self.not_equal(self.local_step, self.accumulation_steps)
# alloc status and clear should be right before gradoperation
init = self.alloc_status()
self.clear_before_grad(init)
grads = self.grad(self.network, weights)(x, b, self.cast(scaling_sens, mstype.float32))
accu_succ = self.hyper_map(update_accu_grads, self.accu_grads, grads)
mean_loss = F.depend(mean_loss, accu_succ)
self.get_status(init)
flag_sum = self.reduce_sum(init, (0,))
overflow = self.less_equal(self.base, flag_sum)
overflow = self.logical_or(self.not_equal(self.accu_overflow, self.zero), overflow)
accu_overflow = self.select(overflow, self.one, self.zero)
self.accu_overflow = self.select(is_accu_step, accu_overflow, self.zero)
is_accu_step = self.reshape(is_accu_step, (()))
if is_accu_step:
succ = False
else:
# apply grad reducer on grads
grads = self.grad_reducer(self.accu_grads)
scaling = scaling_sens * self.degree * self.accumulation_steps
grads = self.hyper_map(F.partial(grad_scale, scaling), grads)
grads = ClipByGlobalNorm()(grads)
accu_overflow = self.overflow_reducer(accu_overflow)
F.control_depend(grads, accu_overflow)
overflow = self.less_equal(self.base, accu_overflow)
accu_succ = self.hyper_map(reset_accu_grads, self.accu_grads)
overflow = F.depend(overflow, accu_succ)
overflow = self.reshape(overflow, (()))
if sens is None:
overflow = self.loss_scaling_manager(self.loss_scale, overflow)
if overflow:
succ = False
else:
succ = self.optimizer(grads)
ret = (mean_loss, overflow, scaling_sens)
return F.depend(ret, succ)
class Net(Cell):
def __init__(self, weight, strategy=None):
super().__init__()
self.mul = P.Mul().shard(strategy)
self.weight = Parameter(weight, "w1")
self.relu = P.ReLU()
self.reduce_sum = P.ReduceSum(keep_dims=True)
def construct(self, x, b):
out = self.mul(x, self.weight)
out = self.relu(out)
out = self.reduce_sum(out)
return out
_x = Tensor(np.ones([2]), dtype=ms.float32)
_b = Tensor(np.ones([16]), dtype=ms.float32)
_w1 = Tensor(np.ones([16]), dtype=ms.float32)
def compile_net(net, grad_accumulation_step):
context.set_context(save_graphs=True)
learning_rate = 0.1
momentum = 0.9
epoch_size = 2
dataset = Dataset(_x, _b)
opt = Momentum(net.trainable_params(), learning_rate, momentum)
update_cell = DynamicLossScaleUpdateCell(loss_scale_value=65536, scale_factor=2, scale_window=1000)
net_wrap = TrainAccumulateStepsWithLossScaleCell(net, opt, scale_update_cell=update_cell,
accumulation_steps=grad_accumulation_step)
model = Model(net_wrap)
model.train(epoch_size, dataset, dataset_sink_mode=False)
context.reset_auto_parallel_context()
def test_grad_accumulation():
grad_accumulation_step = 4
context.set_auto_parallel_context(parallel_mode="semi_auto_parallel", device_num=8, global_rank=0,
grad_accumulation_step=grad_accumulation_step)
strategy = ((2,), (2,))
net = Net(_w1, strategy)
compile_net(net, grad_accumulation_step)