shinken/load.py

   1 #!/usr/bin/env python
   2 #Copyright (C) 2009-2010 :
   3 #    Gabes Jean, naparuba@gmail.com
   4 #    Gerhard Lausser, Gerhard.Lausser@consol.de
   5 #    Gregory Starck, g.starck@gmail.com
   6 #    Hartmut Goebel, h.goebel@goebel-consult.de
   7 #
   8 #This file is part of Shinken.
   9 #
  10 #Shinken is free software: you can redistribute it and/or modify
  11 #it under the terms of the GNU Affero General Public License as published by
  12 #the Free Software Foundation, either version 3 of the License, or
  13 #(at your option) any later version.
  14 #
  15 #Shinken is distributed in the hope that it will be useful,
  16 #but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 #MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 #GNU Affero General Public License for more details.
  19 #
  20 #You should have received a copy of the GNU Affero General Public License
  21 #along with Shinken.  If not, see <http://www.gnu.org/licenses/>.
  22
  23
  24 import time
  25 import math
  26
  27 #EXP_1=1/math.exp(5/60.0)
  28 #EXP_5=1/math.exp(5/(5*60.0))
  29 #EXP_15=1/math.exp(5/(15*60.0))
  30
  31 #From advance load average's code (another of my projects :) )
  32 #def calc_load_load(load, exp,n):
  33 #        load = n + exp*(load - n)
  34 #        return (load, exp)
  35
  36
  37 #This class if for having a easy Load calculation
  38 #without having to send value at regular interval
  39 #(but it's more efficient if you do this :) ) and not
  40 #having a list and all. Just an object, an update and a get
  41 #You can define m : the average is for m minutes. The val is
  42 #the initial value. It's better if it's 0 but you can choice.
  43
  44
  45 class Load:
  46     #m = number of minutes for the average
  47     #val = initial_value
  48     def __init__(self, m=1, initial_value=0):
  49         self.exp = 0 #first exp
  50         self.m = m #Number of minute of the avg
  51         self.last_update = 0 #last update of the value
  52         self.val = initial_value #first value
  53
  54
  55     def update_load(self, new_val):
  56         #The first call do not change the value, just tag
  57         #the begining of last_update
  58         if self.last_update == 0:
  59             self.last_update = time.time()
  60             return
  61         now = time.time()
  62         try:
  63             diff = now - self.last_update
  64             self.exp = 1/math.exp(diff/ (self.m*60.0))
  65             self.val = new_val + self.exp*(self.val - new_val)
  66             self.last_update = now
  67         except OverflowError: #if the time change without notice, we overflow :(
  68             pass
  69         except ZeroDivisionError: #do not care
  70             pass
  71
  72
  73     def get_load(self):
  74         return self.val
  75
  76
  77 if __name__ == '__main__':
  78     l = Load()
  79     t = time.time()
  80     for i in xrange(1, 300):
  81         l.update_load(1)
  82         print '[', int(time.time() - t), ']', l.get_load(), l.exp
  83         time.sleep(5)