Wsrtjtyk

I am new to Keras, and tensorflow in general, and have a problem. I am using some of the loss functions (binary_crossentropy and mean_squared_error mainly) to calculate the loss after prediction. Since Keras only accepts it's own variable type, I am creating one and supply it as an argument. This scenario is executed in a loop (with sleep) as such:

Get appropriate data -> predict -> calculate the lost -> return it.

Since I have multiple models that follow this pattern I created tensorflow graphs and sessions to prevent collision (also when exporting the models' weights I had problem with single graph and session so I had to create distinct ones for every single model).

However, now the memory is rising uncontrollably, from couple of MiB to 700MiB in couple of iterations. I am aware of Keras's clear_session() and gc.collect(), and I use them at the end of every iteration, but the problem is still present. Here I provide a code snippet, which is not the actual code, from the project. I've created separate script in order to isolate the problem:

import tensorflow as tf



from keras import backend as K

from keras.losses import binary_crossentropy, mean_squared_error



from time import time, sleep

import gc

from numpy.random import rand



from os import getpid

from psutil import Process



from csv import DictWriter

from keras import backend as K



this_process = Process(getpid())



graph = tf.Graph()

sess = tf.Session(graph=graph)



cnt = 0

max_c = 500



with open('/home/quark/Desktop/python-test/leak-7.csv', 'a') as file:

    writer = DictWriter(file, fieldnames=['time', 'mem'])

    writer.writeheader()



    while cnt < max_c:  

        with graph.as_default(), sess.as_default():         

            y_true = K.variable(rand(36, 6))

            y_pred = K.variable(rand(36, 6))



            rec_loss = K.eval(binary_crossentropy(y_true, y_pred))

            val_loss = K.eval(mean_squared_error(y_true, y_pred))



            writer.writerow({

                'time': int(time()),

                'mem': this_process.memory_info().rss

            })



        K.clear_session()

        gc.collect()



        cnt += 1

        print(max_c - cnt)

        sleep(0.1)

Additionally, I've added the plot of the memory usage:
Keras memory leak

Any help is appreciated.

I just removed the with statement (probably some tf code), and I don't see any leak. I believe there is a difference between the keras session and the tf default session. So you were not clearing the correct session with K.clear_session(). Probably using tf.reset_default_graph() could work too.

while True: 

    y_true = K.variable(rand(36, 6))

    y_pred = K.variable(rand(36, 6))



    val_loss = K.eval(binary_crossentropy(y_true, y_pred))

    rec_loss = K.eval(mean_squared_error(y_true, y_pred))



    K.clear_session()

    gc.collect()



    sleep(0.1)

At the end, what I did was remove the K.variable() code out of the where statement. In that way, the variables are part of the default graph which is later cleared by K.clear_session().