python统计电脑cpu使用状况

#!/usr/bin/env python
# -*- coding:utf-8 -*- 
#Author: nulige

import os, time

last_worktime=0
last_idletime=0

def get_cpu():
        global last_worktime, last_idletime
        f=open("/proc/stat","r")
        line=""
        while not "cpu " in line: line=f.readline()
        f.close()
        spl=line.split(" ")
        worktime=int(spl[2])+int(spl[3])+int(spl[4])
        idletime=int(spl[5])
        dworktime=(worktime-last_worktime)
        didletime=(idletime-last_idletime)
        rate=float(dworktime)/(didletime+dworktime)
        last_worktime=worktime
        last_idletime=idletime
        if(last_worktime==0): return 0
        return rate

def get_mem_usage_percent():
    try:
        f = open('/proc/meminfo', 'r')
        for line in f:
            if line.startswith('MemTotal:'):
                mem_total = int(line.split()[1])
            elif line.startswith('MemFree:'):
                mem_free = int(line.split()[1])
            elif line.startswith('Buffers:'):
                mem_buffer = int(line.split()[1])
            elif line.startswith('Cached:'):
                mem_cache = int(line.split()[1])
            elif line.startswith('SwapTotal:'):
                vmem_total = int(line.split()[1])
            elif line.startswith('SwapFree:'):
                vmem_free = int(line.split()[1])
            else:
                continue
        f.close()
    except:
        return None
    physical_percent = usage_percent(mem_total - (mem_free + mem_buffer + mem_cache), mem_total)
    virtual_percent = 0
    if vmem_total > 0:
        virtual_percent = usage_percent((vmem_total - vmem_free), vmem_total)
    return physical_percent, virtual_percent

def usage_percent(use, total):
    try:
        ret = (float(use) / total) * 100
    except ZeroDivisionError:
        raise Exception("ERROR - zero division error")
    return ret

statvfs = os.statvfs('/')

total_disk_space = statvfs.f_frsize * statvfs.f_blocks
free_disk_space = statvfs.f_frsize * statvfs.f_bfree
disk_usage = (total_disk_space - free_disk_space) * 100.0 / total_disk_space
disk_usage = int(disk_usage)
disk_tip = "硬盘空间使用率（最大100%）："+str(disk_usage)+"%"
print(disk_tip)

mem_usage = get_mem_usage_percent()
mem_usage = int(mem_usage[0])
mem_tip = "物理内存使用率（最大100%）："+str(mem_usage)+"%"
print(mem_tip)

cpu_usage = int(get_cpu()*100)
cpu_tip = "CPU使用率（最大100%）："+str(cpu_usage)+"%"
print(cpu_tip)

load_average = os.getloadavg()
load_tip = "系统负载（三个数值中有一个超过3就是高）："+str(load_average)
print(load_tip)