目的：计算所有apache进程占用的内存大小以及占物理内存的比例：
思路：利用系统中/proc/meminfo的现有数据进行统计
1、pidof列出服务对应进程的PID
[root@yangliheng ~]# pidof httpd
2、读取PID对应的文件/proc/5355/status（以PID5355为例），遍历得到这个进程对应的占用内存(VmRSS对应的)
[root@yangliheng ~]# cat /proc//status
Name:httpd
State:S (sleeping)
Tgid:
Pid:
PPid:
VmHWM: kB
VmRSS: kB
3、查看/proc/meminfo得到系统的总物理内存
4、就算将Apache 对应所有进程的内存相加，与系统总物理内存相比得到所占比例
$cat /proc/meminfo
MemTotal: kB //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)