title: Python script execution time increases when executed multiple time parallely
body: <p>I have a python script whose execution time is 1.2 second while it is being executed standalone.</p>
  
  <p>But when I execute it 5-6 time parallely ( Am using postman to ping the url multiple times) the execution time shoots up.</p>
  
  <p>Adding the breakdown of the time taken.</p>
  
  <pre><code>1 run -&gt; ~1.2seconds
  2 run -&gt; ~1.8seconds
  3 run -&gt; ~2.3seconds
  4 run -&gt; ~2.9seconds
  5 run -&gt; ~4.0seconds
  6 run -&gt; ~4.5seconds
  7 run -&gt; ~5.2seconds
  8 run -&gt; ~5.2seconds
  9 run -&gt; ~6.4seconds
  10 run -&gt; ~7.1seconds
  </code></pre>
  
  <p>Screenshot of top command(Asked in the comment):
  <a href="https://i.stack.imgur.com/Ec3XC.png" rel="noreferrer"><img src="https://i.stack.imgur.com/Ec3XC.png" alt="enter image description here"></a></p>
  
  <p>This is a sample code:</p>
  
  <pre><code>import psutil
  import os
  import time
  start_time = time.time()
  import cgitb
  cgitb.enable()
  import numpy as np
  import MySQLdb as mysql
  import cv2
  import sys
  import rpy2.robjects as robj
  import rpy2.robjects.numpy2ri
  rpy2.robjects.numpy2ri.activate()
  from rpy2.robjects.packages import importr
  R = robj.r
  DTW = importr('dtw')
  
  process= psutil.Process(os.getpid())
  print " Memory Consumed after libraries load: "
  print process.memory_info()[0]/float(2**20)
  
  st_pt=4
  # Generate our data (numpy arrays)
  template = np.array([range(84),range(84),range(84)]).transpose()
  query = np.array([range(2500000),range(2500000),range(2500000)]).transpose()
  
  
  #time taken
  print(" --- %s seconds ---" % (time.time() - start_time))
  </code></pre>
  
  <p>I also checked my memory consumption using <code>watch -n 1 free -m</code> and memory consumption also increases noticeably.</p>
  
  <p>1) How do I make sure that the execution time of script remain constant everytime.</p>
  
  <p>2) Can I load the libraries permanently so that the time taken by the script to load the libraries and the memory consumed can be minimized?</p>
  
  <p>I made an enviroment and tried using </p>
  
  <p><code>#!/home/ec2-user/anaconda/envs/test_python/</code></p>
  
  <p>but it doesn't make any difference whatsoever.</p>
  
  <p><strong>EDIT:</strong></p>
  
  <p>I have AMAZON's EC2 server with 7.5GB RAM.</p>
  
  <p>My php file with which am calling the python script.</p>
  
  <pre><code>&lt;?php
  
      $response = array("error" =&gt; FALSE); 
  
      if($_SERVER['REQUEST_METHOD']=='GET'){
  
          $response["error"] = FALSE;
          $command =escapeshellcmd(shell_exec("sudo /home/ec2-user/anaconda/envs/anubhaw_python/bin/python2.7 /var/www/cgi-bin/dtw_test_code.py"));
          session_write_close();
          $order=array("\n","\\");
          $cleanData=str_replace($order,'',$command);
          $response["message"]=$cleanData;
  
      } else 
      {
          header('HTTP/1.0 400 Bad Request');
          $response["message"] = "Bad Request.";
      }
      echo json_encode($response);
  ?&gt;
  </code></pre>
  
  <p>Thanks</p>