Now base tensorflow-char-rnn I start a word-rnn project to predict the next word. But I found that speed is too slow in my train data set. Here is my training details:
- Training data size: 1 billion words
- Vocabulary size: 0.75 millions
- RNN model: lstm
- RNN Layer: 2
- Cell size: 200
- Seq length: 20
- Batch size: 40 (too big batch size will be cause OOM exception)
The machine details:
- Amazon p2 instance
- 1 core K80 GPU
- 16G video memory
- 4 core CPU
- 60G memory
In my test, the time of training data 1 epoch is need 17 days! It’s is really too slow, and then I change the seq2seq.rnn_decoder to tf.nn.dynamic_rnn, but the time is still 17 days.
I want to find the too slow reason is caused by my code or it has always been so slow? Because I heard some rumors that Tensorflow rnn is slower than other DL Framework.
This is my model code:
class SeqModel():
def __init__(self, config, infer=False):
self.args = config
if infer:
config.batch_size = 1
config.seq_length = 1
if config.model == 'rnn':
cell_fn = rnn_cell.BasicRNNCell
elif config.model == 'gru':
cell_fn = rnn_cell.GRUCell
elif config.model == 'lstm':
cell_fn = rnn_cell.BasicLSTMCell
else:
raise Exception("model type not supported: {}".format(config.model))
cell = cell_fn(config.hidden_size)
self.cell = cell = rnn_cell.MultiRNNCell([cell] * config.num_layers)
self.input_data = tf.placeholder(tf.int32, [config.batch_size, config.seq_length])
self.targets = tf.placeholder(tf.int32, [config.batch_size, config.seq_length])
self.initial_state = cell.zero_state(config.batch_size, tf.float32)
with tf.variable_scope('rnnlm'):
softmax_w = tf.get_variable("softmax_w", [config.hidden_size, config.vocab_size])
softmax_b = tf.get_variable("softmax_b", [config.vocab_size])
embedding = tf.get_variable("embedding", [config.vocab_size, config.hidden_size])
inputs = tf.nn.embedding_lookup(embedding, self.input_data)
outputs, last_state = tf.nn.dynamic_rnn(cell, inputs, initial_state=self.initial_state)
# [seq_size * batch_size, hidden_size]
output = tf.reshape(tf.concat(1, outputs), [-1, config.hidden_size])
self.logits = tf.matmul(output, softmax_w) + softmax_b
self.probs = tf.nn.softmax(self.logits)
self.final_state = last_state
loss = seq2seq.sequence_loss_by_example([self.logits],
[tf.reshape(self.targets, [-1])],
[tf.ones([config.batch_size * config.seq_length])],
config.vocab_size)
self.cost = tf.reduce_sum(loss) / config.batch_size / config.seq_length
self.lr = tf.Variable(0.0, trainable=False)
tvars = tf.trainable_variables()
grads, _ = tf.clip_by_global_norm(tf.gradients(self.cost, tvars),
config.grad_clip)
optimizer = tf.train.AdamOptimizer(self.lr)
self.train_op = optimizer.apply_gradients(zip(grads, tvars))
Here is the GPU load during the training
Thanks very much.
