# Copyright 2022 Cerebras Systems.
#
# 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.
"""Pytorch Generic Dataloader"""
import random
import torch
from cerebras.modelzoo.common.input_utils import get_streaming_batch_size
from cerebras.modelzoo.common.pytorch_utils import (
BufferedShuffleDataset,
IterableDatasetSampler,
)
from cerebras.modelzoo.data.common.input_utils import num_tasks, task_id
[docs]class GenericDataProcessor:
"""
A Generic PyTorch Data Processor.
:param dict params: dict containing training
input parameters for creating dataset.
Expects the following fields:
- "batch_size" (int): Batch size.
- "shuffle" (bool): Flag to enable data shuffling.
- "shuffle_seed" (int): Shuffle seed.
- "shuffle_buffer" (int): Size of shuffle buffer in samples.
- "num_workers" (int): How many subprocesses to use for data loading.
- "drop_last" (bool): If True and the dataset size is not divisible
by the batch size, the last incomplete batch will be dropped.
- "prefetch_factor" (int): Number of batches loaded in advance by each worker.
- "persistent_workers" (bool): If True, the data loader will not shutdown
the worker processes after a dataset has been consumed once.
"""
[docs] def __init__(self, params):
super(GenericDataProcessor, self).__init__()
self.batch_size = get_streaming_batch_size(params["batch_size"])
self.shuffle = params["shuffle"]
self.shuffle_seed = params.get("shuffle_seed", None)
self.shuffle_buffer = params.get("shuffle_buffer", 10 * self.batch_size)
self.num_workers = params.get("num_workers", 0)
self.drop_last = params.get("drop_last", True)
self.prefetch_factor = params.get("prefetch_factor", 10)
self.persistent_workers = params.get("persistent_workers", True)
assert self.batch_size > 0, "Batch size should be positive."
if not hasattr(self, "dataset"):
assert hasattr(
self, "dataset"
), "The child class should implement self.dataset"
if isinstance(self.dataset, torch.utils.data.IterableDataset):
self.map_style_dataset = False
else:
self.map_style_dataset = True
if not hasattr(self, "data_collator"):
self.data_collator = None
if self.shuffle and not self.map_style_dataset:
# Distributed sampling of an IterableDataset between different tasks
self.dataset = IterableDatasetSampler(
self.dataset, world_size=num_tasks(), rank=task_id()
)
self.sampler = None
self.dataset = BufferedShuffleDataset(
dataset=self.dataset, buffer_size=self.shuffle_buffer
)
else:
torch.manual_seed(self.shuffle_seed)
self.sampler = torch.utils.data.distributed.DistributedSampler(
self.dataset,
num_replicas=num_tasks(),
rank=task_id(),
shuffle=self.shuffle,
seed=self.shuffle_seed,
drop_last=self.drop_last,
)
def _worker_init_fn(self, worker_id):
worker_info = torch.utils.data.get_worker_info()
if worker_info is not None:
worker_id = worker_info.id
# Use a unique seed for each worker.
random.seed(self.shuffle_seed + worker_id)
[docs] def create_dataloader(self):
"""
Classmethod to create the dataloader object.
"""
# Seed BufferedShuffleDataset() in case of single-worker,
# for multiple workers, using _worker_init_fn()
if (
self.num_workers == 0
and self.shuffle_seed
and not self.map_style_dataset
):
random.seed(self.shuffle_seed)
data_loader = torch.utils.data.DataLoader(
self.dataset,
sampler=self.sampler,
batch_size=self.batch_size,
drop_last=self.drop_last,
num_workers=self.num_workers,
prefetch_factor=self.prefetch_factor
if self.num_workers > 0
else None,
persistent_workers=self.persistent_workers
if self.num_workers > 0
else False,
collate_fn=self.data_collator,
worker_init_fn=self._worker_init_fn
if self.num_workers > 0 and not self.map_style_dataset
else None,
)
return data_loader