Source code for pytorch_lightning.strategies.deepspeed
# Copyright The PyTorch Lightning team.
#
# 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 argparse
import contextlib
import json
import logging
import os
import platform
from collections import OrderedDict
from pathlib import Path
from typing import Any, cast, Dict, Generator, List, Mapping, Optional, Tuple, Union
import torch
from torch import Tensor
from torch.nn import Module
from torch.optim import Optimizer
import pytorch_lightning as pl
from pytorch_lightning.accelerators.cuda import CUDAAccelerator
from pytorch_lightning.core.optimizer import _init_optimizers_and_lr_schedulers
from pytorch_lightning.overrides.base import _LightningModuleWrapperBase, _LightningPrecisionModuleWrapperBase
from pytorch_lightning.plugins.environments.cluster_environment import ClusterEnvironment
from pytorch_lightning.plugins.precision import PrecisionPlugin
from pytorch_lightning.strategies.ddp import DDPStrategy
from pytorch_lightning.strategies.utils import _fp_to_half
from pytorch_lightning.trainer.states import TrainerFn
from pytorch_lightning.utilities import GradClipAlgorithmType
from pytorch_lightning.utilities.apply_func import apply_to_collection
from pytorch_lightning.utilities.distributed import (
_get_process_group_backend_from_env,
get_default_process_group_backend_for_device,
log,
)
from pytorch_lightning.utilities.enums import AMPType, PrecisionType
from pytorch_lightning.utilities.exceptions import MisconfigurationException
from pytorch_lightning.utilities.imports import _RequirementAvailable
from pytorch_lightning.utilities.model_helpers import is_overridden
from pytorch_lightning.utilities.optimizer import optimizers_to_device
from pytorch_lightning.utilities.rank_zero import rank_zero_deprecation, rank_zero_info, rank_zero_warn
from pytorch_lightning.utilities.seed import reset_seed
from pytorch_lightning.utilities.types import _LRScheduler, _PATH, LRSchedulerConfig, ReduceLROnPlateau, STEP_OUTPUT
from pytorch_lightning.utilities.warnings import WarningCache
warning_cache = WarningCache()
_DEEPSPEED_AVAILABLE = _RequirementAvailable("deepspeed")
if _DEEPSPEED_AVAILABLE:
import deepspeed
def remove_module_hooks(model: torch.nn.Module) -> None:
# todo (tchaton) awaiting this feature to move upstream to DeepSpeed
for module in model.modules():
module._backward_hooks = OrderedDict()
module._is_full_backward_hook = None
module._forward_hooks = OrderedDict()
module._forward_pre_hooks = OrderedDict()
module._state_dict_hooks = OrderedDict()
module._load_state_dict_pre_hooks = OrderedDict()
class LightningDeepSpeedModule(_LightningModuleWrapperBase):
"""
.. deprecated:: v1.7.1
``LightningDeepSpeedModule`` has been deprecated in v1.7.1 and will be removed in v1.9.0.
"""
def __init__(
self, pl_module: Union["pl.LightningModule", _LightningPrecisionModuleWrapperBase], precision: Union[str, int]
) -> None:
rank_zero_deprecation("`LightningDeepSpeedModule` has been deprecated in v1.7.1 and will be removed in v1.9.0")
super().__init__(pl_module)
self.precision = precision
def forward(self, *inputs: Any, **kwargs: Any) -> Any:
inputs = apply_to_collection(inputs, Tensor, function=self._batch_to)
return super().forward(*inputs, **kwargs)
def _batch_to(self, batch: Tensor) -> Tensor:
if torch.is_floating_point(batch):
if self.precision == PrecisionType.HALF:
return batch.half()
elif self.precision == PrecisionType.BFLOAT:
return batch.bfloat16()
return batch
[docs]class DeepSpeedStrategy(DDPStrategy):
strategy_name = "deepspeed"
DEEPSPEED_ENV_VAR = "PL_DEEPSPEED_CONFIG_PATH"
def __init__(
self,
accelerator: Optional["pl.accelerators.accelerator.Accelerator"] = None,
zero_optimization: bool = True,
stage: int = 2,
remote_device: str = "cpu",
offload_optimizer: bool = False,
offload_parameters: bool = False,
offload_params_device: str = "cpu",
nvme_path: str = "/local_nvme",
params_buffer_count: int = 5,
params_buffer_size: int = 100_000_000,
max_in_cpu: int = 1_000_000_000,
offload_optimizer_device: str = "cpu",
optimizer_buffer_count: int = 4,
block_size: int = 1048576,
queue_depth: int = 8,
single_submit: bool = False,
overlap_events: bool = True,
thread_count: int = 1,
pin_memory: bool = False,
sub_group_size: int = 1_000_000_000_000,
contiguous_gradients: bool = True,
overlap_comm: bool = True,
allgather_partitions: bool = True,
reduce_scatter: bool = True,
allgather_bucket_size: int = 200_000_000,
reduce_bucket_size: int = 200_000_000,
zero_allow_untested_optimizer: bool = True,
logging_batch_size_per_gpu: Union[str, int] = "auto",
config: Optional[Union[_PATH, Dict[str, Any]]] = None,
logging_level: int = logging.WARN,
parallel_devices: Optional[List[torch.device]] = None,
cluster_environment: Optional[ClusterEnvironment] = None,
loss_scale: float = 0,
initial_scale_power: int = 16,
loss_scale_window: int = 1000,
hysteresis: int = 2,
min_loss_scale: int = 1,
partition_activations: bool = False,
cpu_checkpointing: bool = False,
contiguous_memory_optimization: bool = False,
synchronize_checkpoint_boundary: bool = False,
load_full_weights: bool = False,
precision_plugin: Optional[PrecisionPlugin] = None,
process_group_backend: Optional[str] = None,
) -> None:
"""Provides capabilities to run training using the DeepSpeed library, with training optimizations for large
billion parameter models. `For more information: https://pytorch-
lightning.readthedocs.io/en/stable/advanced/model_parallel.html#deepspeed`.
.. warning:: ``DeepSpeedStrategy`` is in beta and subject to change.
Defaults have been set to enable ZeRO-Offload and some have been taken from the link below.
These defaults have been set generally, but may require tuning for optimum performance based on your model size.
`For more information: https://www.deepspeed.ai/docs/config-json/#zero-optimizations-for-fp16-training`.
Arguments:
zero_optimization: Enable ZeRO optimization. This is only compatible with precision=16.
stage: Different stages of the ZeRO Optimizer. 0 is disabled,
1 is optimizer state partitioning, 2 is optimizer+gradient state partitioning,
3 is optimizer+gradient_parameter partitioning using the infinity engine.
remote_device: Device to instantiate the model on initially (``cpu`` or ``nvme``).
offload_optimizer: Enable offloading optimizer memory and computation to CPU or NVMe
based on ``offload_optimizer_device``.
offload_parameters: When using ZeRO Stage 3, Enable offloading parameter memory and computation
to CPU or NVMe based on ``offload_params_device``.
offload_params_device: When offloading parameters choose the device to offload to, ``cpu`` or ``nvme``.
offload_optimizer_device: When offloading optimizer state choose the device to offload to,
``cpu`` or ``nvme``.
params_buffer_count: Number of buffers in buffer pool for
parameter offloading when ``offload_params_device`` is ``nvme``.
params_buffer_size: Size of buffers in buffer pool for parameter offloading
when ``offload_params_device`` is ``nvme``.
max_in_cpu: Number of parameter elements to maintain in CPU memory when offloading to NVMe is enabled.
nvme_path: Filesystem path for NVMe device for optimizer/parameter state offloading.
optimizer_buffer_count: Number of buffers in buffer pool for optimizer state offloading
when ``offload_optimizer_device`` is set to to ``nvme``.
This should be at least the number of states maintained per parameter by the optimizer.
For example, Adam optimizer has 4 states (parameter, gradient, momentum, and variance).
block_size: When using NVMe Offloading, the I/O block size in bytes.
queue_depth: When using NVMe Offloading, the I/O queue depth.
single_submit: When using NVMe Offloading,
submit requests to storage device as multiple individual requests,
as opposed to one block of requests.
overlap_events: When using NVMe Offloading,
submit requests to storage device in an overlapped fashion
without waiting for completion of earlier requests.
thread_count: When using NVMe Offloading,
Intra-request parallelism for each read/write submitted by a user thread.
pin_memory: When using ZeRO stage 3, pin optimizer state memory on CPU.
This could boost throughput at the cost of extra memory overhead.
sub_group_size: When using ZeRO stage 3, defines the number of parameters
within a sub group to offload at a time.
Smaller numbers require more communication, but improve memory efficiency.
contiguous_gradients: Copies gradients to a continuous buffer as they are produced.
Avoids memory fragmentation during backwards. Useful when training large models.
overlap_comm: Overlap the reduction (synchronization) of gradients with the backwards computation.
This is a speed optimization when training across multiple GPUs/machines.
allgather_partitions: All gather updated parameters at the end of training step,
instead of using a series of broadcast collectives.
reduce_scatter: Use reduce/scatter instead of allreduce to average gradients.
allgather_bucket_size: Number of elements to allgather at once.
Used to limit the memory required for larger model sizes, with a tradeoff with speed.
reduce_bucket_size: Number of elements to reduce at once.
Used to limit the memory required for larger model sizes, with a tradeoff with speed.
zero_allow_untested_optimizer: Allow untested optimizers to be used with ZeRO. Currently only Adam is a
DeepSpeed supported optimizer when using ZeRO.
logging_batch_size_per_gpu: Config used in DeepSpeed to calculate verbose timing for logging
on a per sample per second basis (only displayed if logging=logging.INFO).
If set to "auto", the plugin tries to infer this from
the train DataLoader's BatchSampler, else defaults to 1.
To obtain accurate logs when using datasets that do not support batch samplers,
set this to the actual per gpu batch size (trainer.batch_size).
config: Pass in a deepspeed formatted config dict,
or path to a deepspeed config: https://www.deepspeed.ai/docs/config-json.
All defaults will be ignored if a config is passed in.
logging_level: Set logging level for deepspeed.
loss_scale: Loss scaling value for FP16 training.
0.0 results in dynamic loss scaling, otherwise static.
initial_scale_power: Power of the initial dynamic loss scale value. Loss scale is computed
by ``2^initial_scale_power``.
loss_scale_window: Window in which to raise/lower the dynamic FP16 loss scaling value.
hysteresis: FP16 Delay shift in Dynamic Loss scaling.
min_loss_scale: The minimum FP16 dynamic loss scaling value.
partition_activations: Enables partition activation when used with ZeRO stage 3 and model parallelism.
Still requires you to wrap your forward functions in deepspeed.checkpointing.checkpoint.
See `deepspeed tutorial
<https://www.deepspeed.ai/tutorials/megatron/#deepspeed-activation-checkpoints-optional>`_.
cpu_checkpointing: Offloads partitioned activations to CPU if ``partition_activations`` is enabled.
contiguous_memory_optimization: Copies partitioned activations so that they are contiguous in memory.
Not supported by all models.
synchronize_checkpoint_boundary: Insert :func:`torch.cuda.synchronize` at each checkpoint boundary.
load_full_weights: True when loading a single checkpoint file containing the model state dict
when using ZeRO Stage 3. This differs from the DeepSpeed checkpoint which contains shards
per worker.
"""
if not _DEEPSPEED_AVAILABLE:
raise MisconfigurationException(
"To use the `DeepSpeedStrategy`, you must have DeepSpeed installed."
" Install it by running `pip install -U deepspeed`."
)
super().__init__(
accelerator=accelerator,
parallel_devices=parallel_devices,
cluster_environment=cluster_environment,
precision_plugin=precision_plugin,
process_group_backend=process_group_backend,
)
self.config = self._load_config(config)
if self.config is None:
# User has not overridden config, set defaults
self.config = self._create_default_config(
zero_optimization,
zero_allow_untested_optimizer,
logging_batch_size_per_gpu,
offload_optimizer=offload_optimizer,
offload_parameters=offload_parameters,
nvme_path=nvme_path,
offload_params_device=offload_params_device,
params_buffer_count=params_buffer_count,
params_buffer_size=params_buffer_size,
max_in_cpu=max_in_cpu,
pin_memory=pin_memory,
offload_optimizer_device=offload_optimizer_device,
optimizer_buffer_count=optimizer_buffer_count,
block_size=block_size,
queue_depth=queue_depth,
single_submit=single_submit,
overlap_events=overlap_events,
thread_count=thread_count,
partition_activations=partition_activations,
cpu_checkpointing=cpu_checkpointing,
contiguous_memory_optimization=contiguous_memory_optimization,
synchronize_checkpoint_boundary=synchronize_checkpoint_boundary,
stage=stage,
contiguous_gradients=contiguous_gradients,
overlap_comm=overlap_comm,
allgather_partitions=allgather_partitions,
reduce_scatter=reduce_scatter,
allgather_bucket_size=allgather_bucket_size,
reduce_bucket_size=reduce_bucket_size,
sub_group_size=sub_group_size,
)
self._config_initialized = False
deepspeed.utils.logging.logger.setLevel(logging_level)
self.remote_device = remote_device
self.load_full_weights = load_full_weights
# default FP16 parameters.
self.loss_scale = loss_scale
self.initial_scale_power = initial_scale_power
self.loss_scale_window = loss_scale_window
self.hysteresis = hysteresis
self.min_loss_scale = min_loss_scale
def _load_config(self, config: Optional[Union[_PATH, Dict[str, Any]]]) -> Optional[Dict[str, Any]]:
if config is None and self.DEEPSPEED_ENV_VAR in os.environ:
rank_zero_info(f"Loading DeepSpeed config from set {self.DEEPSPEED_ENV_VAR} environment variable")
config = os.environ[self.DEEPSPEED_ENV_VAR]
if isinstance(config, (str, Path)):
if not os.path.isfile(config):
raise MisconfigurationException(
f"You passed in a path to a DeepSpeed config but the path does not exist: {config}"
)
with open(config) as f:
config = json.load(f)
assert isinstance(config, dict) or config is None
return config
def setup_distributed(self) -> None:
reset_seed()
# determine which process we are and world size
self.set_world_ranks()
self._init_deepspeed_distributed()
if not self._config_initialized:
self._format_config()
self._config_initialized = True
[docs] def setup(self, trainer: "pl.Trainer") -> None:
assert self.accelerator is not None
self.accelerator.setup(trainer)
# we set the device so that optimizers can be created with distributed comms.
assert self.lightning_module is not None
self.lightning_module._device = self.root_device
self.setup_optimizers(trainer)
self.setup_precision_plugin()
optimizers_to_device(self.optimizers, self.root_device)
self.init_deepspeed()
self.barrier()
def _init_deepspeed_distributed(self) -> None:
assert self.cluster_environment is not None
if platform.system() != "Windows":
# do not set env variables on windows, allow deepspeed to control setup
self._set_node_environment_variables()
log.info(
"initializing deepspeed distributed: "
f"GLOBAL_RANK: {self.global_rank}, "
f"MEMBER: {self.global_rank + 1}/{self.world_size}"
)
self._process_group_backend = self._get_process_group_backend()
deepspeed.init_distributed(self._process_group_backend, distributed_port=self.cluster_environment.main_port)
def _get_process_group_backend(self) -> str:
return (
self._process_group_backend
or _get_process_group_backend_from_env()
or get_default_process_group_backend_for_device(self.root_device)
)
def _set_node_environment_variables(self) -> None:
assert self.cluster_environment is not None
os.environ["MASTER_ADDR"] = self.cluster_environment.main_address
os.environ["MASTER_PORT"] = str(self.cluster_environment.main_port)
os.environ["RANK"] = str(self.global_rank)
os.environ["WORLD_SIZE"] = str(self.world_size)
os.environ["LOCAL_RANK"] = str(self.local_rank)
@property
def restore_checkpoint_after_setup(self) -> bool:
return True
def _setup_model_and_optimizers(
self, model: Module, optimizers: List[Optimizer]
) -> Tuple["deepspeed.DeepSpeedEngine", List[Optimizer]]:
"""Setup a model and multiple optimizers together.
Currently only a single optimizer is supported.
Return:
The model wrapped into a :class:`deepspeed.DeepSpeedEngine` and a list with a single
deepspeed optimizer.
"""
if len(optimizers) != 1:
raise ValueError(
f"Currently only one optimizer is supported with DeepSpeed."
f" Got {len(optimizers)} optimizers instead."
)
# train_micro_batch_size_per_gpu is used for throughput logging purposes
# normally we set this to the batch size, but it is not available here unless the user provides it
# as part of the config
assert self.config is not None
self.config.setdefault("train_micro_batch_size_per_gpu", 1)
self.model, optimizer = self._setup_model_and_optimizer(model, optimizers[0])
self._set_deepspeed_activation_checkpointing()
return self.model, [optimizer]
def _setup_model_and_optimizer(
self,
model: Module,
optimizer: Optional[Optimizer],
lr_scheduler: Optional[Union[_LRScheduler, ReduceLROnPlateau]] = None,
) -> Tuple["deepspeed.DeepSpeedEngine", Optimizer]:
"""Initialize one model and one optimizer with an optional learning rate scheduler.
This calls :func:`deepspeed.initialize` internally.
"""
model_parameters = filter(lambda p: p.requires_grad, model.parameters())
deepspeed_engine, deepspeed_optimizer, _, _ = deepspeed.initialize(
args=argparse.Namespace(device_rank=self.root_device.index),
config=self.config,
model=model,
model_parameters=model_parameters,
optimizer=optimizer,
lr_scheduler=lr_scheduler,
dist_init_required=False,
)
return deepspeed_engine, deepspeed_optimizer
def init_deepspeed(self) -> None:
assert self.lightning_module is not None
# deepspeed handles gradient clipping internally
if is_overridden("configure_gradient_clipping", self.lightning_module, pl.LightningModule):
rank_zero_warn(
"Since DeepSpeed handles gradient clipping internally, the default"
" `LightningModule.configure_gradient_clipping` implementation will not actually clip gradients."
" The hook will still be called. Consider setting"
" `Trainer(gradient_clip_val=..., gradient_clip_algorithm='norm')`"
" which will use the internal mechanism."
)
if self.lightning_module.trainer.gradient_clip_algorithm == GradClipAlgorithmType.VALUE:
raise MisconfigurationException("DeepSpeed does not support clipping gradients by value.")
if not isinstance(self.accelerator, CUDAAccelerator):
raise MisconfigurationException(
f"DeepSpeed strategy is only supported on GPU but `{self.accelerator.__class__.__name__}` is used."
)
accumulation_scheduler = self.lightning_module.trainer.accumulation_scheduler
if accumulation_scheduler.epochs != [0]:
raise MisconfigurationException(
"DeepSpeed currently does not support different `accumulate_grad_batches` at different epochs."
)
assert isinstance(self.model, (pl.LightningModule, _LightningPrecisionModuleWrapperBase))
model = _LightningModuleWrapperBase(pl_module=self.model)
if self.lightning_module.trainer and self.lightning_module.trainer.training:
self._initialize_deepspeed_train(model)
else:
self._initialize_deepspeed_inference(model)
def _init_optimizers(self) -> Tuple[Optimizer, Optional[LRSchedulerConfig], Optional[int]]:
assert self.lightning_module is not None
optimizers, lr_schedulers, optimizer_frequencies = _init_optimizers_and_lr_schedulers(self.lightning_module)
if len(optimizers) > 1 or len(lr_schedulers) > 1:
raise MisconfigurationException(
"DeepSpeed currently only supports single optimizer, single optional scheduler."
)
return (
optimizers[0],
lr_schedulers[0] if lr_schedulers else None,
optimizer_frequencies[0] if optimizer_frequencies else None,
)
@property
def zero_stage_3(self) -> bool:
assert isinstance(self.config, dict)
zero_optimization = self.config.get("zero_optimization")
return zero_optimization is not None and zero_optimization.get("stage") == 3
def _initialize_deepspeed_train(self, model: Module) -> None:
optimizer, scheduler = None, None
assert isinstance(self.config, dict)
if "optimizer" in self.config:
rank_zero_info(
"You have specified an optimizer and/or scheduler within the DeepSpeed config."
" It is recommended to define it in `LightningModule.configure_optimizers`."
)
lr_scheduler = None
else:
optimizer, lr_scheduler, _ = self._init_optimizers()
if lr_scheduler is not None:
scheduler = lr_scheduler.scheduler
model, deepspeed_optimizer = self._setup_model_and_optimizer(model, optimizer, scheduler)
self._set_deepspeed_activation_checkpointing()
# although we set these here, deepspeed manages the specific optimizer logic
self.optimizers = [deepspeed_optimizer]
deepspeed_scheduler = model.lr_scheduler
if deepspeed_scheduler is not None:
# disable deepspeed lr scheduling as lightning manages scheduling
model.lr_scheduler = None
if lr_scheduler is None:
lr_scheduler = LRSchedulerConfig(deepspeed_scheduler, interval="step", opt_idx=0)
else:
lr_scheduler.scheduler = deepspeed_scheduler
self.lr_scheduler_configs = [lr_scheduler]
self.model = model
[docs] @contextlib.contextmanager
def model_sharded_context(self) -> Generator[None, None, None]:
if self.zero_stage_3:
assert self._config_initialized
if self.precision_plugin.precision == PrecisionType.HALF:
dtype = torch.float16
elif self.precision_plugin.precision == PrecisionType.BFLOAT:
dtype = torch.bfloat16
else:
dtype = torch.float32
model_parallel_context = deepspeed.zero.Init(
remote_device=self.remote_device, pin_memory=True, config_dict_or_path=self.config, dtype=dtype
)
else:
model_parallel_context = super().model_sharded_context()
with model_parallel_context:
yield
def _set_deepspeed_activation_checkpointing(self) -> None:
assert isinstance(self.config, dict)
if self.config.get("activation_checkpointing"):
checkpoint_config = self.config["activation_checkpointing"]
deepspeed.checkpointing.configure(
mpu_=None,
partition_activations=checkpoint_config.get("partition_activations"),
contiguous_checkpointing=checkpoint_config.get("contiguous_memory_optimization"),
checkpoint_in_cpu=checkpoint_config.get("cpu_checkpointing"),
profile=checkpoint_config.get("profile"),
)
def _initialize_deepspeed_inference(self, model: Module) -> None:
# todo: Currently DeepSpeed requires optimizers at inference to partition weights correctly
assert isinstance(self.config, dict)
optimizer, scheduler = None, None
if "optimizer" not in self.config:
rank_zero_info(
"You have not specified an optimizer or scheduler within the DeepSpeed config."
" Using `configure_optimizers` to define optimizer and scheduler."
)
optimizer, lr_scheduler, _ = self._init_optimizers()
if lr_scheduler is not None:
scheduler = lr_scheduler.scheduler
# todo: this is required for DeepSpeed throughput timers
inference_config = {"train_micro_batch_size_per_gpu": 1}
if "fp16" in self.config:
inference_config.update({"fp16": self.config["fp16"]})
if self.zero_stage_3:
inference_config.update(
{
"zero_allow_untested_optimizer": self.config["zero_allow_untested_optimizer"],
"zero_optimization": self.config["zero_optimization"],
}
)
# Remove all module hooks before initializing new model
remove_module_hooks(model)
model, _, _, _ = deepspeed.initialize(
args=argparse.Namespace(device_rank=self.root_device.index),
config=inference_config,
model=model,
optimizer=optimizer,
lr_scheduler=scheduler,
model_parameters=[],
dist_init_required=False,
)
self.model = model
@property
def lightning_module(self) -> Optional["pl.LightningModule"]:
# the model may not be wrapped with DeepEngine & _LightningModuleWrapperBase if calling this too early
module = getattr(self.model, "module", self.model)
module = module.module if isinstance(module, _LightningModuleWrapperBase) else module
assert isinstance(module, pl.LightningModule) or module is None
return module
@property
def distributed_sampler_kwargs(self) -> Dict[str, int]:
distributed_sampler_kwargs = dict(num_replicas=self.world_size, rank=self.global_rank)
return distributed_sampler_kwargs
[docs] def setup_optimizers(self, trainer: "pl.Trainer") -> None:
"""Creates optimizers and schedulers.
Args:
trainer: the Trainer, these optimizers should be connected to
"""
if trainer.state.fn not in (TrainerFn.FITTING, TrainerFn.TUNING):
return
# Skip initializing optimizers here as DeepSpeed handles optimizers via config.
# User may have specified config options instead in configure_optimizers, but this is handled
# via `_initialize_deepspeed_train`
# empty optimizers, schedulers and frequencies
self.optimizers = []
self.lr_scheduler_configs = []
self.optimizer_frequencies = []
@property
def handles_gradient_accumulation(self) -> bool:
"""Whether the plugin handles gradient accumulation internally."""
return True
def _format_config(self) -> None:
if self.config is None:
raise MisconfigurationException(
"To use DeepSpeed you must pass in a DeepSpeed config dict, or a path to a JSON config."
" See: https://pytorch-lightning.readthedocs.io/en/stable/advanced/model_parallel.html#deepspeed"
)
self._format_batch_size_and_grad_accum_config()
self._format_precision_config()
def _format_batch_size_and_grad_accum_config(self) -> None:
# todo: using lite, we do not support these variables within the config
assert isinstance(self.config, dict)
if self.lightning_module is None:
return
if "gradient_accumulation_steps" in self.config:
raise MisconfigurationException(
"Do not set `gradient_accumulation_steps` in the DeepSpeed config"
" as this will be set with the `accumulate_grad_batches` argument passed via the Lightning Trainer."
)
self.config["gradient_accumulation_steps"] = self.lightning_module.trainer.accumulate_grad_batches
if "train_micro_batch_size_per_gpu" not in self.config:
batch_size = self._auto_select_batch_size()
self.config["train_micro_batch_size_per_gpu"] = batch_size
if "gradient_clipping" not in self.config:
self.config["gradient_clipping"] = self.lightning_module.trainer.gradient_clip_val or 0.0
def _auto_select_batch_size(self) -> int:
# train_micro_batch_size_per_gpu is used for throughput logging purposes
# by default we try to use the batch size of the loader
assert self.lightning_module is not None
batch_size = 1
train_dl_source = self.lightning_module.trainer._data_connector._train_dataloader_source
if train_dl_source.is_defined():
try:
train_dataloader = train_dl_source.dataloader()
if hasattr(train_dataloader, "batch_sampler"):
batch_size = train_dataloader.batch_sampler.batch_size # type: ignore[union-attr]
# broad exception on purpose as `source.dataloader()` will fail if the dataloader requires `setup`
# to have been called before
except Exception:
if self.global_rank == 0:
deepspeed.utils.logging.logger.warning(
"Tried to infer the batch size for internal deepspeed logging from the `train_dataloader()`. "
"To ensure DeepSpeed logging remains correct, please manually pass the plugin with the "
"batch size, `Trainer(strategy=DeepSpeedStrategy(logging_batch_size_per_gpu=batch_size))`."
)
return batch_size
def _format_precision_config(self) -> None:
assert isinstance(self.config, dict)
if self.precision_plugin.precision == PrecisionType.HALF:
if "fp16" not in self.config and self.precision_plugin.amp_type == AMPType.NATIVE:
# FP16 is a DeepSpeed standalone AMP implementation
rank_zero_info("Enabling DeepSpeed FP16.")
self.config["fp16"] = {
"enabled": True,
"loss_scale": self.loss_scale,
"initial_scale_power": self.initial_scale_power,
"loss_scale_window": self.loss_scale_window,
"hysteresis": self.hysteresis,
"min_loss_scale": self.min_loss_scale,
}
elif "amp" not in self.config and self.precision_plugin.amp_type == AMPType.APEX:
rank_zero_info("Enabling DeepSpeed APEX Implementation.")
self.config["amp"] = {"enabled": True, "opt_level": self.precision_plugin.amp_level}
elif "bf16" not in self.config and self.precision_plugin.precision == PrecisionType.BFLOAT:
rank_zero_info("Enabling DeepSpeed BF16.")
self.config["bf16"] = {"enabled": True}
def _create_default_config(
self,
zero_optimization: bool,
zero_allow_untested_optimizer: bool,
logging_batch_size_per_gpu: Union[str, int],
partition_activations: bool,
cpu_checkpointing: bool,
contiguous_memory_optimization: bool,
synchronize_checkpoint_boundary: bool,
offload_optimizer: bool,
offload_parameters: bool,
nvme_path: str,
offload_params_device: str,
params_buffer_count: int,
params_buffer_size: int,
max_in_cpu: int,
offload_optimizer_device: str,
optimizer_buffer_count: int,
pin_memory: bool,
block_size: int,
queue_depth: int,
single_submit: bool,
overlap_events: bool,
thread_count: int,
**zero_kwargs: Any,
) -> Dict:
cfg = {
"activation_checkpointing": {
"partition_activations": partition_activations,
"cpu_checkpointing": cpu_checkpointing,
"contiguous_memory_optimization": contiguous_memory_optimization,
"synchronize_checkpoint_boundary": synchronize_checkpoint_boundary,
},
"aio": {
"block_size": block_size,
"queue_depth": queue_depth,
"single_submit": single_submit,
"overlap_events": overlap_events,
"thread_count": thread_count,
},
}
if zero_optimization:
zero_config = zero_kwargs
if offload_optimizer:
zero_config["offload_optimizer"] = {
"device": offload_optimizer_device,
"nvme_path": nvme_path,
"buffer_count": optimizer_buffer_count,
"pin_memory": pin_memory,
}
if offload_parameters:
zero_config["offload_param"] = {
"device": offload_params_device,
"nvme_path": nvme_path,
"buffer_count": params_buffer_count,
"buffer_size": params_buffer_size,
"max_in_cpu": max_in_cpu,
"pin_memory": pin_memory,
}
cfg = {
"zero_allow_untested_optimizer": zero_allow_untested_optimizer,
"zero_optimization": zero_config,
**cfg,
}
if logging_batch_size_per_gpu != "auto":
cfg = {"train_micro_batch_size_per_gpu": logging_batch_size_per_gpu, **cfg}
return cfg
@property
def deepspeed_engine(self) -> "deepspeed.DeepSpeedEngine":
return self.model
@property
def _multi_device(self) -> bool:
return self.num_processes > 1 or self.num_nodes > 1
[docs] def save_checkpoint(self, checkpoint: Dict, filepath: _PATH, storage_options: Optional[Any] = None) -> None:
"""Save model/training states as a checkpoint file through state-dump and file-write.
Args:
checkpoint: The checkpoint state dictionary
filepath: write-target file's path
storage_options: not used for ``DeepSpeedStrategy`` as ``CheckpointIO`` is not used
Raises:
TypeError:
If ``storage_options`` arg is passed in
"""
# broadcast the filepath from rank 0 to ensure all the states are saved in a common filepath
filepath = self.broadcast(filepath)
if storage_options is not None:
raise TypeError(
"`Trainer.save_checkpoint(..., storage_options=...)` with `storage_options` arg"
f" is not supported for `{self.__class__.__name__}` as `CheckpointIO` is not used."
)
if self.zero_stage_3 and self._multi_device and self.is_global_zero:
warning_cache.warn(
"When saving the DeepSpeed Stage 3 checkpoint, "
"each worker will save a shard of the checkpoint within a directory. "
"If a single file is required after training, "
"see https://pytorch-lightning.readthedocs.io/en/stable/advanced/model_parallel.html#"
"deepspeed-zero-stage-3-single-file for instructions."
)
# Use deepspeed's internal checkpointing function to handle partitioned weights across processes
# dump states as a checkpoint dictionary object
_exclude_keys = ["state_dict", "optimizer_states"]
checkpoint = {k: v for k, v in checkpoint.items() if k not in _exclude_keys}
self.deepspeed_engine.save_checkpoint(filepath, client_state=checkpoint, tag="checkpoint")
def load_checkpoint(self, checkpoint_path: _PATH) -> Dict[str, Any]:
if self.load_full_weights and self.zero_stage_3:
# Broadcast to ensure we load from the rank 0 checkpoint
# This doesn't have to be the case when using deepspeed sharded checkpointing
checkpoint_path = cast(_PATH, self.broadcast(checkpoint_path))
return super().load_checkpoint(checkpoint_path)
# Rely on deepspeed to load the checkpoint and necessary information
assert self.lightning_module is not None
from pytorch_lightning.trainer.states import TrainerFn
is_fitting = self.lightning_module.trainer.state.fn == TrainerFn.FITTING
_, client_state = self.deepspeed_engine.load_checkpoint(
checkpoint_path, load_optimizer_states=is_fitting, load_lr_scheduler_states=False
)
if client_state is None:
raise MisconfigurationException(
"DeepSpeed was unable to load the checkpoint. Ensure you passed in a DeepSpeed compatible checkpoint "
"or a single checkpoint file with `Trainer(strategy=DeepSpeedStrategy(load_full_weights=True))`."
)
return client_state
@property
def lightning_restore_optimizer(self) -> bool:
assert self.lightning_module is not None
# managed by DeepSpeed
if self.load_full_weights and self.zero_stage_3 and self.lightning_module.trainer.state.fn == TrainerFn.FITTING:
rank_zero_warn(
"A single checkpoint file has been given. This means optimizer states cannot be restored."
" If you'd like to restore these states, you must provide a path to the originally saved DeepSpeed"
" checkpoint. When using ZeRO 3, the original path should be a directory."
)
return False
def load_model_state_dict(self, checkpoint: Mapping[str, Any]) -> None:
# override to do nothing, deepspeed engine already loaded the weights in `load_checkpoint()`
if self.load_full_weights and self.zero_stage_3:
self.model_to_device()
self._restore_zero_state(checkpoint)
def _restore_zero_state(self, ckpt: Mapping[str, Any]) -> None:
"""Overrides the normal load_state_dict behaviour in PyTorch to ensure we gather parameters that may be
sharded across processes before loading the state dictionary when using ZeRO stage 3. This is then
automatically synced across processes.
Args:
ckpt: The ckpt file.
"""
assert self.lightning_module is not None
def load(module: torch.nn.Module, prefix: str = "") -> None:
missing_keys: List[str] = []
unexpected_keys: List[str] = []
error_msgs: List[str] = []
state_dict = ckpt["state_dict"]
# copy state_dict so _load_from_state_dict can modify it
metadata = getattr(state_dict, "_metadata", None)
state_dict = state_dict.copy()
if metadata is not None:
state_dict._metadata = metadata
local_metadata = {} if metadata is None else metadata.get(prefix[:-1], {})
# because zero3 puts placeholders in model params, this context
# manager gathers (unpartitions) the params of the current layer, then loads from
# the state dict and then re-partitions them again
with deepspeed.zero.GatheredParameters(list(module.parameters(recurse=False)), modifier_rank=0):
if self.is_global_zero:
module._load_from_state_dict(
state_dict=state_dict,
prefix=prefix,
local_metadata=local_metadata,
strict=True,
missing_keys=missing_keys,
unexpected_keys=unexpected_keys,
error_msgs=error_msgs,
)
for name, child in module._modules.items():
if child is not None:
load(child, prefix + name + ".")
load(self.lightning_module, prefix="")
def load_optimizer_state_dict(self, checkpoint: Mapping[str, Any]) -> None:
# override to do nothing, deepspeed engine already loaded the states in `load_checkpoint()`
pass
@classmethod
def register_strategies(cls, strategy_registry: Dict) -> None:
strategy_registry.register("deepspeed", cls, description="Default DeepSpeed Strategy")
strategy_registry.register("deepspeed_stage_1", cls, description="DeepSpeed with ZeRO Stage 1 enabled", stage=1)
strategy_registry.register("deepspeed_stage_2", cls, description="DeepSpeed with ZeRO Stage 2 enabled", stage=2)
strategy_registry.register(
"deepspeed_stage_2_offload",
cls,
description="DeepSpeed ZeRO Stage 2 and CPU Offload",
stage=2,
offload_optimizer=True,
)
strategy_registry.register("deepspeed_stage_3", cls, description="DeepSpeed ZeRO Stage 3", stage=3)
strategy_registry.register(
"deepspeed_stage_3_offload",
cls,
description="DeepSpeed ZeRO Stage 3 and CPU Offload",
stage=3,
offload_optimizer=True,
offload_parameters=True,
)
strategy_registry.register(
"deepspeed_stage_3_offload_nvme",
cls,
description="DeepSpeed ZeRO Stage 3 and NVMe Offload",
stage=3,
offload_optimizer=True,
offload_parameters=True,
remote_device="nvme",
offload_params_device="nvme",
offload_optimizer_device="nvme",
)
[docs] def batch_to_device(self, batch: Any, device: Optional[torch.device] = None, dataloader_idx: int = 0) -> Any:
batch = apply_to_collection(batch, Tensor, function=_fp_to_half, precision=self.precision_plugin.precision)
return super().batch_to_device(batch, device, dataloader_idx)
[docs] def validation_step(self, *args: Any, **kwargs: Any) -> Optional[STEP_OUTPUT]:
assert self.model is not None
with self.precision_plugin.val_step_context():
return self.model(*args, **kwargs)
[docs] def test_step(self, *args: Any, **kwargs: Any) -> Optional[STEP_OUTPUT]:
assert self.model is not None
with self.precision_plugin.test_step_context():
return self.model(*args, **kwargs)
[docs] def predict_step(self, *args: Any, **kwargs: Any) -> STEP_OUTPUT:
assert self.model is not None
with self.precision_plugin.predict_step_context():
return self.model(*args, **kwargs)
