cube-studio/job-template/job/horovod/demo.py
2022-07-26 20:47:20 +08:00

96 lines
3.4 KiB
Python

import sys
import tensorflow as tf
import horovod
import horovod.tensorflow as hvd
def main():
# Horovod: initialize Horovod.
hvd.init()
# Horovod: pin GPU to be used to process local rank (one GPU per process)
gpus = tf.config.experimental.list_physical_devices('GPU')
for gpu in gpus:
tf.config.experimental.set_memory_growth(gpu, True)
if gpus:
tf.config.experimental.set_visible_devices(gpus[hvd.local_rank()], 'GPU')
(mnist_images, mnist_labels), _ = \
tf.keras.datasets.mnist.load_data(path='mnist-%d.npz' % hvd.rank())
dataset = tf.data.Dataset.from_tensor_slices(
(tf.cast(mnist_images[..., tf.newaxis] / 255.0, tf.float32),
tf.cast(mnist_labels, tf.int64))
)
dataset = dataset.repeat().shuffle(10000).batch(128)
mnist_model = tf.keras.Sequential([
tf.keras.layers.Conv2D(32, [3, 3], activation='relu'),
tf.keras.layers.Conv2D(64, [3, 3], activation='relu'),
tf.keras.layers.MaxPooling2D(pool_size=(2, 2)),
tf.keras.layers.Dropout(0.25),
tf.keras.layers.Flatten(),
tf.keras.layers.Dense(128, activation='relu'),
tf.keras.layers.Dropout(0.5),
tf.keras.layers.Dense(10, activation='softmax')
])
loss = tf.losses.SparseCategoricalCrossentropy()
# Horovod: adjust learning rate based on number of GPUs.
opt = tf.optimizers.Adam(0.001 * hvd.size())
checkpoint_dir = './checkpoints'
checkpoint = tf.train.Checkpoint(model=mnist_model, optimizer=opt)
@tf.function
def training_step(images, labels, first_batch):
with tf.GradientTape() as tape:
probs = mnist_model(images, training=True)
loss_value = loss(labels, probs)
# Horovod: add Horovod Distributed GradientTape.
tape = hvd.DistributedGradientTape(tape)
grads = tape.gradient(loss_value, mnist_model.trainable_variables)
opt.apply_gradients(zip(grads, mnist_model.trainable_variables))
# Horovod: broadcast initial variable states from rank 0 to all other processes.
# This is necessary to ensure consistent initialization of all workers when
# training is started with random weights or restored from a checkpoint.
#
# Note: broadcast should be done after the first gradient step to ensure optimizer
# initialization.
if first_batch:
hvd.broadcast_variables(mnist_model.variables, root_rank=0)
hvd.broadcast_variables(opt.variables(), root_rank=0)
return loss_value
# Horovod: adjust number of steps based on number of GPUs.
for batch, (images, labels) in enumerate(dataset.take(10000 // hvd.size())):
loss_value = training_step(images, labels, batch == 0)
if batch % 10 == 0 and hvd.local_rank() == 0:
print('Step #%d\tLoss: %.6f' % (batch, loss_value))
# Horovod: save checkpoints only on worker 0 to prevent other workers from
# corrupting it.
if hvd.rank() == 0:
checkpoint.save(checkpoint_dir)
if __name__ == '__main__':
if len(sys.argv) == 4:
# run training through horovod.run
np = int(sys.argv[1])
hosts = sys.argv[2]
comm = sys.argv[3]
print('Running training through horovod.run')
horovod.run(main, np=np, hosts=hosts, use_gloo=comm == 'gloo', use_mpi=comm == 'mpi')
else:
# this is running via horovodrun
main()