# Copyright 2018 The TensorFlow Authors. All Rights Reserved. # # 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. # ============================================================================== """Common util functions and classes used by both keras cifar and imagenet.""" from __future__ import absolute_import from __future__ import division from __future__ import print_function import multiprocessing import os from absl import flags import numpy as np import tensorflow as tf from tensorflow.python.keras.optimizer_v2 import gradient_descent as gradient_descent_v2 from official.utils.flags import core as flags_core from official.utils.misc import keras_utils FLAGS = flags.FLAGS BASE_LEARNING_RATE = 0.1 # This matches Jing's version. TRAIN_TOP_1 = 'training_accuracy_top_1' LR_SCHEDULE = [ # (multiplier, epoch to start) tuples (1.0, 5), (0.1, 30), (0.01, 60), (0.001, 80) ] def learning_rate_schedule(current_epoch, current_batch, batches_per_epoch, batch_size): """Handles linear scaling rule, gradual warmup, and LR decay. Scale learning rate at epoch boundaries provided in LR_SCHEDULE by the provided scaling factor. Args: current_epoch: integer, current epoch indexed from 0. current_batch: integer, current batch in the current epoch, indexed from 0. batches_per_epoch: integer, number of steps in an epoch. batch_size: integer, total batch sized. Returns: Adjusted learning rate. """ initial_lr = BASE_LEARNING_RATE * batch_size / 256 epoch = current_epoch + float(current_batch) / batches_per_epoch warmup_lr_multiplier, warmup_end_epoch = LR_SCHEDULE[0] if epoch < warmup_end_epoch: # Learning rate increases linearly per step. return initial_lr * warmup_lr_multiplier * epoch / warmup_end_epoch for mult, start_epoch in LR_SCHEDULE: if epoch >= start_epoch: learning_rate = initial_lr * mult else: break return learning_rate class LearningRateBatchScheduler(tf.keras.callbacks.Callback): """Callback to update learning rate on every batch (not epoch boundaries). N.B. Only support Keras optimizers, not TF optimizers. Attributes: schedule: a function that takes an epoch index and a batch index as input (both integer, indexed from 0) and returns a new learning rate as output (float). """ def __init__(self, schedule, batch_size, num_images): super(LearningRateBatchScheduler, self).__init__() self.schedule = schedule self.batches_per_epoch = num_images / batch_size self.batch_size = batch_size self.epochs = -1 self.prev_lr = -1 def on_epoch_begin(self, epoch, logs=None): if not hasattr(self.model.optimizer, 'learning_rate'): raise ValueError('Optimizer must have a "learning_rate" attribute.') self.epochs += 1 def on_batch_begin(self, batch, logs=None): """Executes before step begins.""" lr = self.schedule(self.epochs, batch, self.batches_per_epoch, self.batch_size) if not isinstance(lr, (float, np.float32, np.float64)): raise ValueError('The output of the "schedule" function should be float.') if lr != self.prev_lr: self.model.optimizer.learning_rate = lr # lr should be a float here self.prev_lr = lr tf.compat.v1.logging.debug( 'Epoch %05d Batch %05d: LearningRateBatchScheduler ' 'change learning rate to %s.', self.epochs, batch, lr) class PiecewiseConstantDecayWithWarmup( tf.keras.optimizers.schedules.LearningRateSchedule): """Piecewise constant decay with warmup schedule.""" def __init__(self, batch_size, epoch_size, warmup_epochs, boundaries, multipliers, compute_lr_on_cpu=True, name=None): super(PiecewiseConstantDecayWithWarmup, self).__init__() if len(boundaries) != len(multipliers) - 1: raise ValueError('The length of boundaries must be 1 less than the ' 'length of multipliers') base_lr_batch_size = 256 num_batches_per_epoch = epoch_size // batch_size self.rescaled_lr = BASE_LEARNING_RATE * batch_size / base_lr_batch_size self.step_boundaries = [float(num_batches_per_epoch) * x for x in boundaries] self.lr_values = [self.rescaled_lr * m for m in multipliers] self.warmup_steps = warmup_epochs * num_batches_per_epoch self.compute_lr_on_cpu = compute_lr_on_cpu self.name = name self.learning_rate_ops_cache = {} def __call__(self, step): if tf.executing_eagerly(): return self._get_learning_rate(step) # In an eager function or graph, the current implementation of optimizer # repeatedly call and thus create ops for the learning rate schedule. To # avoid this, we cache the ops if not executing eagerly. graph = tf.compat.v1.get_default_graph() if graph not in self.learning_rate_ops_cache: if self.compute_lr_on_cpu: with tf.device('/device:CPU:0'): self.learning_rate_ops_cache[graph] = self._get_learning_rate(step) else: self.learning_rate_ops_cache[graph] = self._get_learning_rate(step) return self.learning_rate_ops_cache[graph] def _get_learning_rate(self, step): """Compute learning rate at given step.""" with tf.compat.v1.name_scope(self.name, 'PiecewiseConstantDecayWithWarmup', [self.rescaled_lr, self.step_boundaries, self.lr_values, self.warmup_steps, self.compute_lr_on_cpu]): def warmup_lr(step): return self.rescaled_lr * ( tf.cast(step, tf.float32) / tf.cast(self.warmup_steps, tf.float32)) def piecewise_lr(step): return tf.compat.v1.train.piecewise_constant( step, self.step_boundaries, self.lr_values) return tf.cond(step < self.warmup_steps, lambda: warmup_lr(step), lambda: piecewise_lr(step)) def get_config(self): return { 'rescaled_lr': self.rescaled_lr, 'step_boundaries': self.step_boundaries, 'lr_values': self.lr_values, 'warmup_steps': self.warmup_steps, 'compute_lr_on_cpu': self.compute_lr_on_cpu, 'name': self.name } def set_gpu_thread_mode_and_count(flags_obj): """Set GPU thread mode and count, and adjust dataset threads count.""" cpu_count = multiprocessing.cpu_count() tf.compat.v1.logging.info('Logical CPU cores: %s', cpu_count) # Allocate private thread pool for each GPU to schedule and launch kernels per_gpu_thread_count = flags_obj.per_gpu_thread_count or 2 os.environ['TF_GPU_THREAD_MODE'] = flags_obj.tf_gpu_thread_mode os.environ['TF_GPU_THREAD_COUNT'] = str(per_gpu_thread_count) tf.compat.v1.logging.info('TF_GPU_THREAD_COUNT: %s', os.environ['TF_GPU_THREAD_COUNT']) tf.compat.v1.logging.info('TF_GPU_THREAD_MODE: %s', os.environ['TF_GPU_THREAD_MODE']) # Limit data preprocessing threadpool to CPU cores minus number of total GPU # private threads and memory copy threads. total_gpu_thread_count = per_gpu_thread_count * flags_obj.num_gpus num_runtime_threads = flags_obj.num_gpus if not flags_obj.datasets_num_private_threads: flags_obj.datasets_num_private_threads = min( cpu_count - total_gpu_thread_count - num_runtime_threads, flags_obj.num_gpus * 8) tf.compat.v1.logging.info('Set datasets_num_private_threads to %s', flags_obj.datasets_num_private_threads) def get_optimizer(learning_rate=0.1): """Returns optimizer to use.""" # The learning_rate is overwritten at the beginning of each step by callback. return gradient_descent_v2.SGD(learning_rate=learning_rate, momentum=0.9) # TODO(hongkuny,haoyuzhang): make cifar model use_tensor_lr to clean up code. def get_callbacks(learning_rate_schedule_fn=None, num_images=None): """Returns common callbacks.""" time_callback = keras_utils.TimeHistory(FLAGS.batch_size, FLAGS.log_steps) callbacks = [time_callback] if not FLAGS.use_tensor_lr and learning_rate_schedule_fn: lr_callback = LearningRateBatchScheduler( learning_rate_schedule_fn, batch_size=FLAGS.batch_size, num_images=num_images) callbacks.append(lr_callback) if FLAGS.enable_tensorboard: tensorboard_callback = tf.keras.callbacks.TensorBoard( log_dir=FLAGS.model_dir) callbacks.append(tensorboard_callback) if FLAGS.profile_steps: profiler_callback = keras_utils.get_profiler_callback( FLAGS.model_dir, FLAGS.profile_steps, FLAGS.enable_tensorboard) callbacks.append(profiler_callback) return callbacks def build_stats(history, eval_output, callbacks): """Normalizes and returns dictionary of stats. Args: history: Results of the training step. Supports both categorical_accuracy and sparse_categorical_accuracy. eval_output: Output of the eval step. Assumes first value is eval_loss and second value is accuracy_top_1. callbacks: a list of callbacks which might include a time history callback used during keras.fit. Returns: Dictionary of normalized results. """ stats = {} if eval_output: stats['accuracy_top_1'] = eval_output[1].item() stats['eval_loss'] = eval_output[0].item() if history and history.history: train_hist = history.history # Gets final loss from training. stats['loss'] = train_hist['loss'][-1].item() # Gets top_1 training accuracy. if 'categorical_accuracy' in train_hist: stats[TRAIN_TOP_1] = train_hist['categorical_accuracy'][-1].item() elif 'sparse_categorical_accuracy' in train_hist: stats[TRAIN_TOP_1] = train_hist['sparse_categorical_accuracy'][-1].item() if not callbacks: return stats # Look for the time history callback which was used during keras.fit for callback in callbacks: if isinstance(callback, keras_utils.TimeHistory): timestamp_log = callback.timestamp_log stats['step_timestamp_log'] = timestamp_log stats['train_finish_time'] = callback.train_finish_time if len(timestamp_log) > 1: stats['avg_exp_per_second'] = ( callback.batch_size * callback.log_steps * (len(callback.timestamp_log)-1) / (timestamp_log[-1].timestamp - timestamp_log[0].timestamp)) return stats def define_keras_flags(dynamic_loss_scale=True): """Define flags for Keras models.""" flags_core.define_base(clean=True, num_gpu=True, run_eagerly=True, train_epochs=True, epochs_between_evals=True, distribution_strategy=True) flags_core.define_performance(num_parallel_calls=False, synthetic_data=True, dtype=True, all_reduce_alg=True, num_packs=True, tf_gpu_thread_mode=True, datasets_num_private_threads=True, dynamic_loss_scale=dynamic_loss_scale, loss_scale=True, fp16_implementation=True, tf_data_experimental_slack=True, enable_xla=True, force_v2_in_keras_compile=True) flags_core.define_image() flags_core.define_benchmark() flags_core.define_distribution() flags.adopt_module_key_flags(flags_core) flags.DEFINE_boolean(name='enable_eager', default=False, help='Enable eager?') flags.DEFINE_boolean(name='skip_eval', default=False, help='Skip evaluation?') # TODO(b/135607288): Remove this flag once we understand the root cause of # slowdown when setting the learning phase in Keras backend. flags.DEFINE_boolean( name='set_learning_phase_to_train', default=True, help='If skip eval, also set Keras learning phase to 1 (training).') flags.DEFINE_boolean( name='explicit_gpu_placement', default=False, help='If not using distribution strategy, explicitly set device scope ' 'for the Keras training loop.') flags.DEFINE_boolean(name='use_trivial_model', default=False, help='Whether to use a trivial Keras model.') flags.DEFINE_boolean(name='report_accuracy_metrics', default=True, help='Report metrics during training and evaluation.') flags.DEFINE_boolean(name='use_tensor_lr', default=False, help='Use learning rate tensor instead of a callback.') flags.DEFINE_boolean( name='enable_tensorboard', default=False, help='Whether to enable Tensorboard callback.') flags.DEFINE_integer( name='train_steps', default=None, help='The number of steps to run for training. If it is larger than ' '# batches per epoch, then use # batches per epoch. When this flag is ' 'set, only one epoch is going to run for training.') flags.DEFINE_string( name='profile_steps', default=None, help='Save profiling data to model dir at given range of steps. The ' 'value must be a comma separated pair of positive integers, specifying ' 'the first and last step to profile. For example, "--profile_steps=2,4" ' 'triggers the profiler to process 3 steps, starting from the 2nd step. ' 'Note that profiler has a non-trivial performance overhead, and the ' 'output file can be gigantic if profiling many steps.') flags.DEFINE_boolean( name='data_delay_prefetch', default=False, help='Add a small delay in tf.data prefetch to prioritize memory copy of ' 'other tensors over the data minibatch for the (T+1)th step. It should ' 'help improve performance using EagerIterator and function. The codepath ' 'when enabling this feature is experimental and will be removed once the ' 'corresponding performance features are fully supported in TensorFlow.') flags.DEFINE_boolean( name='batchnorm_spatial_persistent', default=True, help='Enable the spacial persistent mode for CuDNN batch norm kernel.') flags.DEFINE_boolean( name='enable_get_next_as_optional', default=False, help='Enable get_next_as_optional behavior in DistributedIterator.') flags.DEFINE_boolean( name='enable_checkpoint_and_export', default=False, help='Whether to enable a checkpoint callback and export the savedmodel.') flags.DEFINE_string( name='tpu', default='', help='TPU address to connect to.') flags.DEFINE_integer( name='steps_per_loop', default=1, help='Number of steps per graph-mode loop. Only training step happens ' 'inside the loop. Callbacks will not be called inside. Will be capped at ' 'steps per epoch.') def get_synth_input_fn(height, width, num_channels, num_classes, dtype=tf.float32, drop_remainder=True): """Returns an input function that returns a dataset with random data. This input_fn returns a data set that iterates over a set of random data and bypasses all preprocessing, e.g. jpeg decode and copy. The host to device copy is still included. This used to find the upper throughput bound when tuning the full input pipeline. Args: height: Integer height that will be used to create a fake image tensor. width: Integer width that will be used to create a fake image tensor. num_channels: Integer depth that will be used to create a fake image tensor. num_classes: Number of classes that should be represented in the fake labels tensor dtype: Data type for features/images. drop_remainder: A boolean indicates whether to drop the remainder of the batches. If True, the batch dimension will be static. Returns: An input_fn that can be used in place of a real one to return a dataset that can be used for iteration. """ # pylint: disable=unused-argument def input_fn(is_training, data_dir, batch_size, *args, **kwargs): """Returns dataset filled with random data.""" # Synthetic input should be within [0, 255]. inputs = tf.random.truncated_normal([height, width, num_channels], dtype=dtype, mean=127, stddev=60, name='synthetic_inputs') labels = tf.random.uniform([1], minval=0, maxval=num_classes - 1, dtype=tf.int32, name='synthetic_labels') # Cast to float32 for Keras model. labels = tf.cast(labels, dtype=tf.float32) data = tf.data.Dataset.from_tensors((inputs, labels)).repeat() # `drop_remainder` will make dataset produce outputs with known shapes. data = data.batch(batch_size, drop_remainder=drop_remainder) data = data.prefetch(buffer_size=tf.data.experimental.AUTOTUNE) return data return input_fn def data_delay_prefetch(): """Use unstable code for perf tuning purposes.""" if not FLAGS.use_synthetic_data: _monkey_patch_org_create_device_dataset() def set_cudnn_batchnorm_mode(): """Set CuDNN batchnorm mode for better performance. Note: Spatial Persistent mode may lead to accuracy losses for certain models. """ if FLAGS.batchnorm_spatial_persistent: os.environ['TF_USE_CUDNN_BATCHNORM_SPATIAL_PERSISTENT'] = '1' else: os.environ.pop('TF_USE_CUDNN_BATCHNORM_SPATIAL_PERSISTENT', None) # TODO(haoyuzhang): remove this monkey patch when the "prefetch with slack" # feature is available in tf.data. def _monkey_patch_org_create_device_dataset(): """Monkey-patch `_create_device_dataset` method with delayed prefetch.""" import ast # pylint: disable=g-import-not-at-top import inspect # pylint: disable=g-import-not-at-top from tensorflow.python.data.ops import multi_device_iterator_ops # pylint: disable=g-import-not-at-top tf.compat.v1.logging.info( 'Using monkey-patched version of MultiDeviceIterator. It should be ' 'removed when the prefetch with slack feature is implemented in tf.data.') cls_multi_device_iterator = ast.parse( inspect.getsource(multi_device_iterator_ops.MultiDeviceIterator)) org_create_device_dataset_code = inspect.getsource( multi_device_iterator_ops.MultiDeviceIterator._create_device_dataset) # pylint: disable=protected-access code_lines = org_create_device_dataset_code.split('\n') # Insert in reverse order to avoid line number shift by previous insertions code_lines.insert(5, ' ds = ds.apply(sleep_ops.sleep(11000))') # 11ms code_lines.insert(2, ' from tensorflow.python.data.experimental.ops import sleep as sleep_ops') # pylint: disable=line-too-long patched_code = '\n'.join(line[2:] for line in code_lines) cls_multi_device_iterator.body[0].body[2] = ast.parse(patched_code).body[0] exec(compile(cls_multi_device_iterator, '', 'exec'), # pylint: disable=exec-used multi_device_iterator_ops.__dict__)