title: How to set specific gpu in tensorflow?
body: <p>I want to specify the gpu to run my process. And I set it as follows:</p>
  
  <pre><code>import tensorflow as tf
  with tf.device('/gpu:0'):
      a = tf.constant(3.0)
  with tf.Session() as sess:
      while True:
          print sess.run(a)
  </code></pre>
  
  <p>However it still allocate memory in both my two gpus. </p>
  
  <pre><code>|    0      7479    C   python                         5437MiB 
  |    1      7479    C   python                         5437MiB 
  </code></pre>