python计算apache总内存

#!/usr/bin/env python
import os
from subprocess import Popen, PIPE
def getPid():
    p=Popen(['pidof','httpd'],stdout=PIPE,stderr=PIPE)
    pids = p.stdout.read().split()
    return pids

def paresPidFile(pids):
     sum =0
     for i in pids:
         fn = os.path.join('/proc/',i,'status')
         with open(fn) as fd:
            for line in fd:
                 if line.startswith('VmRSS'):
                     http_mem =int(line.split()[1])
                     sum += http_mem
                     break
     return sum
def total_mem(f):
    with open(f) as fd:
        for line in fd:
             if line.startswith('MemTotal'):
                    total_mem =int(line.split()[1])
                    return total_mem
if __name__ =='__main__':
    pids = getPid()
    http_mem = paresPidFile(pids)
    total = total_mem('/proc/meminfo')
    print"Apache memory is: %s KB"% http_mem
    print "Percent: %.2f%%"%(http_mem/float(total)*100)