CPU efficiency on Linux with Python

cpueff.py

#!/usr/bin/env python

from time import sleep

ncpus = sum([ 1 for x in open("/proc/cpuinfo").read().split("\n") if "bogomips" in x ])

def getup():
  tot,idle = open("/proc/uptime").read().split(" ")
  return float(tot)*ncpus,float(idle)

def loop():
  tot0,idle0 = getup()
  while True:
    sleep(5)
    tot,idle = getup()
    dtot = tot-tot0
    didle = idle-idle0
    eff = ncpus * 100 * (dtot-didle)/dtot
    eff = eff if eff >= 0 else 0
    print "dtot=%.2f didle=%.2f eff=%.2f" % (dtot,didle,eff)
    tot0 = tot
    idle0 = idle

print "number of cpus: %d" % ncpus
loop()