# Copyright (c) Facebook, Inc. and its affiliates.
import datetime
import json
import logging
import os
import time
from collections import defaultdict
from contextlib import contextmanager
from typing import Optional
import torch
from fvcore.common.history_buffer import HistoryBuffer
from detectron2.utils.file_io import PathManager
__all__ = [
"get_event_storage",
"JSONWriter",
"TensorboardXWriter",
"CommonMetricPrinter",
"EventStorage",
]
_CURRENT_STORAGE_STACK = []
[docs]def get_event_storage():
"""
Returns:
The :class:`EventStorage` object that's currently being used.
Throws an error if no :class:`EventStorage` is currently enabled.
"""
assert len(
_CURRENT_STORAGE_STACK
), "get_event_storage() has to be called inside a 'with EventStorage(...)' context!"
return _CURRENT_STORAGE_STACK[-1]
class EventWriter:
"""
Base class for writers that obtain events from :class:`EventStorage` and process them.
"""
def write(self):
raise NotImplementedError
def close(self):
pass
[docs]class JSONWriter(EventWriter):
"""
Write scalars to a json file.
It saves scalars as one json per line (instead of a big json) for easy parsing.
Examples parsing such a json file:
::
$ cat metrics.json | jq -s '.[0:2]'
[
{
"data_time": 0.008433341979980469,
"iteration": 19,
"loss": 1.9228371381759644,
"loss_box_reg": 0.050025828182697296,
"loss_classifier": 0.5316952466964722,
"loss_mask": 0.7236229181289673,
"loss_rpn_box": 0.0856662318110466,
"loss_rpn_cls": 0.48198649287223816,
"lr": 0.007173333333333333,
"time": 0.25401854515075684
},
{
"data_time": 0.007216215133666992,
"iteration": 39,
"loss": 1.282649278640747,
"loss_box_reg": 0.06222952902317047,
"loss_classifier": 0.30682939291000366,
"loss_mask": 0.6970193982124329,
"loss_rpn_box": 0.038663312792778015,
"loss_rpn_cls": 0.1471673548221588,
"lr": 0.007706666666666667,
"time": 0.2490077018737793
}
]
$ cat metrics.json | jq '.loss_mask'
0.7126231789588928
0.689423680305481
0.6776131987571716
...
"""
[docs] def __init__(self, json_file, window_size=20):
"""
Args:
json_file (str): path to the json file. New data will be appended if the file exists.
window_size (int): the window size of median smoothing for the scalars whose
`smoothing_hint` are True.
"""
self._file_handle = PathManager.open(json_file, "a")
self._window_size = window_size
self._last_write = -1
[docs] def write(self):
storage = get_event_storage()
to_save = defaultdict(dict)
for k, (v, iter) in storage.latest_with_smoothing_hint(self._window_size).items():
# keep scalars that have not been written
if iter <= self._last_write:
continue
to_save[iter][k] = v
if len(to_save):
all_iters = sorted(to_save.keys())
self._last_write = max(all_iters)
for itr, scalars_per_iter in to_save.items():
scalars_per_iter["iteration"] = itr
self._file_handle.write(json.dumps(scalars_per_iter, sort_keys=True) + "\n")
self._file_handle.flush()
try:
os.fsync(self._file_handle.fileno())
except AttributeError:
pass
[docs] def close(self):
self._file_handle.close()
[docs]class TensorboardXWriter(EventWriter):
"""
Write all scalars to a tensorboard file.
"""
[docs] def __init__(self, log_dir: str, window_size: int = 20, **kwargs):
"""
Args:
log_dir (str): the directory to save the output events
window_size (int): the scalars will be median-smoothed by this window size
kwargs: other arguments passed to `torch.utils.tensorboard.SummaryWriter(...)`
"""
self._window_size = window_size
from torch.utils.tensorboard import SummaryWriter
self._writer = SummaryWriter(log_dir, **kwargs)
self._last_write = -1
[docs] def write(self):
storage = get_event_storage()
new_last_write = self._last_write
for k, (v, iter) in storage.latest_with_smoothing_hint(self._window_size).items():
if iter > self._last_write:
self._writer.add_scalar(k, v, iter)
new_last_write = max(new_last_write, iter)
self._last_write = new_last_write
# storage.put_{image,histogram} is only meant to be used by
# tensorboard writer. So we access its internal fields directly from here.
if len(storage._vis_data) >= 1:
for img_name, img, step_num in storage._vis_data:
self._writer.add_image(img_name, img, step_num)
# Storage stores all image data and rely on this writer to clear them.
# As a result it assumes only one writer will use its image data.
# An alternative design is to let storage store limited recent
# data (e.g. only the most recent image) that all writers can access.
# In that case a writer may not see all image data if its period is long.
storage.clear_images()
if len(storage._histograms) >= 1:
for params in storage._histograms:
self._writer.add_histogram_raw(**params)
storage.clear_histograms()
[docs] def close(self):
if hasattr(self, "_writer"): # doesn't exist when the code fails at import
self._writer.close()
[docs]class CommonMetricPrinter(EventWriter):
"""
Print **common** metrics to the terminal, including
iteration time, ETA, memory, all losses, and the learning rate.
It also applies smoothing using a window of 20 elements.
It's meant to print common metrics in common ways.
To print something in more customized ways, please implement a similar printer by yourself.
"""
[docs] def __init__(self, max_iter: Optional[int] = None, window_size: int = 20):
"""
Args:
max_iter: the maximum number of iterations to train.
Used to compute ETA. If not given, ETA will not be printed.
window_size (int): the losses will be median-smoothed by this window size
"""
self.logger = logging.getLogger(__name__)
self._max_iter = max_iter
self._window_size = window_size
self._last_write = None # (step, time) of last call to write(). Used to compute ETA
def _get_eta(self, storage) -> Optional[str]:
if self._max_iter is None:
return ""
iteration = storage.iter
try:
eta_seconds = storage.history("time").median(1000) * (self._max_iter - iteration - 1)
storage.put_scalar("eta_seconds", eta_seconds, smoothing_hint=False)
return str(datetime.timedelta(seconds=int(eta_seconds)))
except KeyError:
# estimate eta on our own - more noisy
eta_string = None
if self._last_write is not None:
estimate_iter_time = (time.perf_counter() - self._last_write[1]) / (
iteration - self._last_write[0]
)
eta_seconds = estimate_iter_time * (self._max_iter - iteration - 1)
eta_string = str(datetime.timedelta(seconds=int(eta_seconds)))
self._last_write = (iteration, time.perf_counter())
return eta_string
[docs] def write(self):
storage = get_event_storage()
iteration = storage.iter
if iteration == self._max_iter:
# This hook only reports training progress (loss, ETA, etc) but not other data,
# therefore do not write anything after training succeeds, even if this method
# is called.
return
try:
data_time = storage.history("data_time").avg(20)
except KeyError:
# they may not exist in the first few iterations (due to warmup)
# or when SimpleTrainer is not used
data_time = None
try:
iter_time = storage.history("time").global_avg()
except KeyError:
iter_time = None
try:
lr = "{:.5g}".format(storage.history("lr").latest())
except KeyError:
lr = "N/A"
eta_string = self._get_eta(storage)
if torch.cuda.is_available():
max_mem_mb = torch.cuda.max_memory_allocated() / 1024.0 / 1024.0
else:
max_mem_mb = None
# NOTE: max_mem is parsed by grep in "dev/parse_results.sh"
self.logger.info(
" {eta}iter: {iter} {losses} {time}{data_time}lr: {lr} {memory}".format(
eta=f"eta: {eta_string} " if eta_string else "",
iter=iteration,
losses=" ".join(
[
"{}: {:.4g}".format(k, v.median(self._window_size))
for k, v in storage.histories().items()
if "loss" in k
]
),
time="time: {:.4f} ".format(iter_time) if iter_time is not None else "",
data_time="data_time: {:.4f} ".format(data_time) if data_time is not None else "",
lr=lr,
memory="max_mem: {:.0f}M".format(max_mem_mb) if max_mem_mb is not None else "",
)
)
[docs]class EventStorage:
"""
The user-facing class that provides metric storage functionalities.
In the future we may add support for storing / logging other types of data if needed.
"""
[docs] def __init__(self, start_iter=0):
"""
Args:
start_iter (int): the iteration number to start with
"""
self._history = defaultdict(HistoryBuffer)
self._smoothing_hints = {}
self._latest_scalars = {}
self._iter = start_iter
self._current_prefix = ""
self._vis_data = []
self._histograms = []
[docs] def put_image(self, img_name, img_tensor):
"""
Add an `img_tensor` associated with `img_name`, to be shown on
tensorboard.
Args:
img_name (str): The name of the image to put into tensorboard.
img_tensor (torch.Tensor or numpy.array): An `uint8` or `float`
Tensor of shape `[channel, height, width]` where `channel` is
3. The image format should be RGB. The elements in img_tensor
can either have values in [0, 1] (float32) or [0, 255] (uint8).
The `img_tensor` will be visualized in tensorboard.
"""
self._vis_data.append((img_name, img_tensor, self._iter))
[docs] def put_scalar(self, name, value, smoothing_hint=True):
"""
Add a scalar `value` to the `HistoryBuffer` associated with `name`.
Args:
smoothing_hint (bool): a 'hint' on whether this scalar is noisy and should be
smoothed when logged. The hint will be accessible through
:meth:`EventStorage.smoothing_hints`. A writer may ignore the hint
and apply custom smoothing rule.
It defaults to True because most scalars we save need to be smoothed to
provide any useful signal.
"""
name = self._current_prefix + name
history = self._history[name]
value = float(value)
history.update(value, self._iter)
self._latest_scalars[name] = (value, self._iter)
existing_hint = self._smoothing_hints.get(name)
if existing_hint is not None:
assert (
existing_hint == smoothing_hint
), "Scalar {} was put with a different smoothing_hint!".format(name)
else:
self._smoothing_hints[name] = smoothing_hint
[docs] def put_scalars(self, *, smoothing_hint=True, **kwargs):
"""
Put multiple scalars from keyword arguments.
Examples:
storage.put_scalars(loss=my_loss, accuracy=my_accuracy, smoothing_hint=True)
"""
for k, v in kwargs.items():
self.put_scalar(k, v, smoothing_hint=smoothing_hint)
[docs] def put_histogram(self, hist_name, hist_tensor, bins=1000):
"""
Create a histogram from a tensor.
Args:
hist_name (str): The name of the histogram to put into tensorboard.
hist_tensor (torch.Tensor): A Tensor of arbitrary shape to be converted
into a histogram.
bins (int): Number of histogram bins.
"""
ht_min, ht_max = hist_tensor.min().item(), hist_tensor.max().item()
# Create a histogram with PyTorch
hist_counts = torch.histc(hist_tensor, bins=bins)
hist_edges = torch.linspace(start=ht_min, end=ht_max, steps=bins + 1, dtype=torch.float32)
# Parameter for the add_histogram_raw function of SummaryWriter
hist_params = dict(
tag=hist_name,
min=ht_min,
max=ht_max,
num=len(hist_tensor),
sum=float(hist_tensor.sum()),
sum_squares=float(torch.sum(hist_tensor ** 2)),
bucket_limits=hist_edges[1:].tolist(),
bucket_counts=hist_counts.tolist(),
global_step=self._iter,
)
self._histograms.append(hist_params)
[docs] def history(self, name):
"""
Returns:
HistoryBuffer: the scalar history for name
"""
ret = self._history.get(name, None)
if ret is None:
raise KeyError("No history metric available for {}!".format(name))
return ret
[docs] def histories(self):
"""
Returns:
dict[name -> HistoryBuffer]: the HistoryBuffer for all scalars
"""
return self._history
[docs] def latest(self):
"""
Returns:
dict[str -> (float, int)]: mapping from the name of each scalar to the most
recent value and the iteration number its added.
"""
return self._latest_scalars
[docs] def latest_with_smoothing_hint(self, window_size=20):
"""
Similar to :meth:`latest`, but the returned values
are either the un-smoothed original latest value,
or a median of the given window_size,
depend on whether the smoothing_hint is True.
This provides a default behavior that other writers can use.
"""
result = {}
for k, (v, itr) in self._latest_scalars.items():
result[k] = (
self._history[k].median(window_size) if self._smoothing_hints[k] else v,
itr,
)
return result
[docs] def smoothing_hints(self):
"""
Returns:
dict[name -> bool]: the user-provided hint on whether the scalar
is noisy and needs smoothing.
"""
return self._smoothing_hints
[docs] def step(self):
"""
User should either: (1) Call this function to increment storage.iter when needed. Or
(2) Set `storage.iter` to the correct iteration number before each iteration.
The storage will then be able to associate the new data with an iteration number.
"""
self._iter += 1
@property
def iter(self):
"""
Returns:
int: The current iteration number. When used together with a trainer,
this is ensured to be the same as trainer.iter.
"""
return self._iter
@iter.setter
def iter(self, val):
self._iter = int(val)
@property
def iteration(self):
# for backward compatibility
return self._iter
def __enter__(self):
_CURRENT_STORAGE_STACK.append(self)
return self
def __exit__(self, exc_type, exc_val, exc_tb):
assert _CURRENT_STORAGE_STACK[-1] == self
_CURRENT_STORAGE_STACK.pop()
[docs] @contextmanager
def name_scope(self, name):
"""
Yields:
A context within which all the events added to this storage
will be prefixed by the name scope.
"""
old_prefix = self._current_prefix
self._current_prefix = name.rstrip("/") + "/"
yield
self._current_prefix = old_prefix
[docs] def clear_images(self):
"""
Delete all the stored images for visualization. This should be called
after images are written to tensorboard.
"""
self._vis_data = []
[docs] def clear_histograms(self):
"""
Delete all the stored histograms for visualization.
This should be called after histograms are written to tensorboard.
"""
self._histograms = []