Source code for modelzoo.transformers.data_processing.h5_map_dataset.dataset

# Copyright 2022 Cerebras Systems.
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import logging

import torch

import cerebras_pytorch as cstorch
import cerebras_pytorch.distributed as dist
from cerebras_pytorch.distributed import get_worker_state
from modelzoo.common.pytorch.input_utils import get_streaming_batch_size
from modelzoo.vision.pytorch.input.utils import create_worker_cache

from .readers import H5Reader, Mixture
from .samplers import CBSampler


[docs]class RestartableDataLoader(torch.utils.data.DataLoader): """ The state we care about for allowing deterministic restart of instances of `HDF5Dataset` is the total number of samples streamed globally, which gets consumed by the sampler. Accordingly each worker saves the number of samples that it has streamed in `state_dict()`. We aggregate these together via summation to save the global number of samples streamed across all workers, which is the same thing that is used to set the state of the sampler on state dict load. """
[docs] def __init__(self, *args, **kwargs): # keep track of how many samples were streamed in the previous portion # of the run so that we can track cumulative samples streamed in the # state_dict self.previous_samples_streamed = 0 super().__init__(*args, **kwargs)
[docs] def state_dict(self): """ Save number of samples streamed for current worker """ worker_state = get_worker_state() return { "samples_streamed": worker_state.samples_streamed, "previous_samples_streamed": self.previous_samples_streamed, }
[docs] def load_state_dict(self, state_dict): """ Set sampler state with the total number of samples streamed globally """ self.validate_state_dict(state_dict) self.previous_samples_streamed = state_dict["samples_streamed"] if state_dict["seed"] != self.dataset.seed: raise ValueError( f"shuffle seed {self.dataset.seed} doesn't match the seed used " f"for the previous portion of the run {state_dict['seed']}" ) self.dataset.sampler.set_state(state_dict["samples_streamed"])
[docs] def aggregate_state_dict(self, worker_states): """ Sum samples streamed across all workers to get the number of samples streamed globally """ return { "samples_streamed": sum( sd["samples_streamed"] for sd in worker_states ) + worker_states[0]["previous_samples_streamed"], "seed": self.dataset.seed, }
[docs] def deaggregate_state_dict(self, aggregated_state_dict): """ No deaggregation needed since the sampler needs the global number of samples streamed """ return aggregated_state_dict
@staticmethod def validate_state_dict(sd): if len(sd) != 2 or "samples_streamed" not in sd or "seed" not in sd: raise RuntimeError( "The keys in state_dict must be 'samples_streamed' and 'seed', " f"found {sd.keys()}. This means that the dataloader state in " "the checkpoint you are loading from is not compatible with " "the dataloader currently in use. Consider re-running without " "loading the dataloader state." )
[docs]class HDF5Dataset(torch.utils.data.Dataset): """ Dynamically read samples from disk for using mapping paradigms. It supports two different data formats on disk. The first is data stored in an H5 file in the shape `(num_tokens,)`, i.e. a series of documents tokenized and concatenated together. We call this format the 'corpus' format The second format is H5 data of shape `(num_sequences, ...)`, i.e. data has already been tokenized and split into sequences. We call this format the 'sample' format. The corpus format supports flexible choice of MSL backed by a single copy of the data on disk. Both formats support deterministic restart, and a data order that is independent of the configuration of the cluster you are running on. I.e. you can pause a run, increase or decrease the number of systems you are running on, and restart the run with no change in data order. When used in combination with shuffling, this implementation relies on random access reads to disk to dynamically split samples into sequences and shuffle. Users with unusually slow storage should look out for data loading bottlenecks and might consider using `use_worker_cache=True` if disk access is indeed a bottleneck. Args: params (dict): a dictionary containing the following fields: - "data_dir" (str or list[str]): the path to the HDF5 files. Exactly one of "data_dir" or "mixture" must be specified. - "batch_size" (int): batch size - "shuffle" (bool): whether or not to shuffle the dataset. Defaults to `False` - "shuffle_seed" (int): seed used for deterministic shuffling. Defaults to 0. - "use_worker_cache" (bool): whether or not to copy data to storage that is directly attached to each individual worker node. Useful when your network storage is unusually slow, but otherwise discouraged. - "max_sequence_length" (int): the sequence length of samples produced by the dataloader. When using the 'corpus' data format, the same preprocessed data will work with any max sequence length, so this may be set at runtime. When using the 'sample' format this must be set to `None`. - "data_subset" (str): an optional specification to only consider a subset of the full dataset, useful for sequence length scheduling and multi-epoch testing. Expected to be a comma separated list of ranges, e.g. '0.0-0.5' or '0.1-0.3,0.7-1.0'. Specifying '0.0-0.5' creates a dataset from the first half of the data on disk and disregards the second half. - "mixture" list[dict]: an optional specification of multiple datasets to mix over to create one single weighted combination. Each element must be a dictionary containing keys `data_dir` and `weight`. `data_dir` serves the same purpose as mentioned above. `weight` defines the probability with which this dataset should be sampled from. Weights are normalized to sum to 1. Optionally, the dictionary may also contain a `data_subset` field which functions the same as the `data_subset` argument above. - "drop_last" (bool): similar to the PyTorch drop_last setting except that samples that when set to `True`, samples that would have been dropped at the end of one epoch are yielded at the start of the next epoch so that there is no data loss. This is necessary for a data ordering that is independent of the distributed setup being used. - "num_samples" (int): the number of samples to shuffle over (if shuffling is enabled). In multi-epoch training, it is common to set this to the total number of samples that you plan to train on so that epochs are not sequential but instead shuffled together for potentially improved convergence. - "sort_files" (bool): whether or not the reader should sort the input files. This is included for backwards compatibility and should almost always be set to `True`. """
[docs] def __init__(self, params): self.use_worker_cache = params.get("use_worker_cache", False) self.msl = params.get("max_sequence_length", None) shuffle = params.get("shuffle", False) self._seed = params.get("shuffle_seed", 0) data_dir = params.get("data_dir", None) mixture_params = params.get("mixture", None) batch_size = get_streaming_batch_size(params["batch_size"]) micro_batch_size = params.get("micro_batch_size") drop_last = params.get("drop_last", True) num_samples = params.get("num_samples", None) self.sort_files = params.get("sort_files", True) if data_dir and mixture_params: raise ValueError( "you can't specify `data_dir` and `mixture` at the same time" ) if data_dir is not None: self.reader = self._set_up_reader( data_dir, params.get("data_subset", None) ) else: self.reader = Mixture( [ self._set_up_reader( x["data_dir"], x.get("data_subset", None) ) for x in mixture_params ], [x["weight"] for x in mixture_params], interleave=not shuffle, seed=self._seed, ) self.sampler = CBSampler( self, shuffle=shuffle, seed=self._seed, shard=True, batch_size=batch_size, drop_last=drop_last, num_samples=num_samples, ) self.map_fn = None if self.by_sample and shuffle: logging.warning( "You have chosen to use the sample data format with shuffling. " "If you are doing a single-epoch run, it is usually beneficial " "to shuffle at preprocessing time instead of runtime. On some " "storage setups, shuffling at runtime can cause performance " "degredation." )
@property def by_sample(self): return self.reader.by_sample @property def seed(self): return self._seed def map(self, fn): if self.map_fn is not None: raise ValueError( f"You may only apply one map function to a H5MapDataset" ) self.map_fn = fn def _set_up_reader(self, data_dir, subset): if not isinstance(data_dir, list): data_dir = [data_dir] if self.use_worker_cache and cstorch.use_cs() and dist.is_streamer(): data_dir = [create_worker_cache(d) for d in data_dir] reader = H5Reader(data_dir, self.msl, True, subset, self.sort_files) return reader def __getitem__(self, i): x = self.reader[i] if self.map_fn is not None: return self.map_fn(x) return x def __len__(self): return len(self.reader)