今天介紹獲取本機記憶體狀況並將其儲存的Python程式.
系統記憶體的使用狀況對我們了解系統運作情況及判斷瓶頸,
有重要的參考價值,系統雖然提供許多細緻的指令,來了解
當前記憶體的使用狀況,若能長期的蒐集,對系統記憶體後續
的增加就有數據提供參考.或是使用者反應某某時段系統反應
較慢,我們即可利用蒐集的歷史數據,進行判斷.

以下為建立資料檔的Python程式.

#!/usr/bin/env python
# -------------------
# Create Memory RRD
# -------------------

import rrdtool

rrdtool.create(
    'memory.rrd', '--step', '60',
    'DS:mtotl:GAUGE:120:0:U',
    'DS:mbuff:GAUGE:120:0:U',
    'DS:mcach:GAUGE:120:0:U',
    'DS:mfree:GAUGE:120:0:U',
    'RRA:AVERAGE:0.5:1:2880',
    'RRA:AVERAGE:0.5:30:672',
    'RRA:AVERAGE:0.5:60:744',
    'RRA:AVERAGE:0.5:720:732',
    'RRA:MAX:0.5:1:2880',
    'RRA:MAX:0.5:30:672',
    'RRA:MAX:0.5:60:744',
    'RRA:MAX:0.5:720:732',
    'RRA:MIN:0.5:1:2880',
    'RRA:MIN:0.5:30:672',
    'RRA:MIN:0.5:60:744',
    'RRA:MIN:0.5:720:732',
    'RRA:LAST:0.5:1:2880',
    'RRA:LAST:0.5:30:672',
    'RRA:LAST:0.5:60:744',
    'RRA:LAST:0.5:720:732')

執行後會建立資料檔,接著是蒐集資料的程式.

#!/usr/bin/env python
# -------------------
# Update Memory RRD
# -------------------

import rrdtool
import time

def get_meminfo():
    with open('/proc/meminfo', 'r') as memtxt:
        mem_list = ('total', 'free', 'buffer', 'cached')
        mems = memtxt.readlines()
        for mem in mems:
            item, vals = mem.split(':')
            if item == 'MemTotal':
                memtot = int(vals.split()[0])
            if item == 'MemFree':
                memfree = int(vals.split()[0])
            if item == 'Buffers':
                membuff = int(vals.split()[0])
            if item == 'Cached':
                memcach = int(vals.split()[0])
        #
        memdict = dict(zip(mem_list, (memtot, memfree, membuff, memcach)))
        return memdict
#
def update_mem_rrd(rrdfile):
    """ update memory rrd file"""
    memdict = get_meminfo()
    total = memdict['total']
    free = memdict['free']
    mbuffer = memdict['buffer']
    cached = memdict['cached']
    rrdtool.update(rrdfile, 'N:' + `total` + ':' + `mbuffer` \
                   + ':' + `cached` + ':' + `free`)
#
    

if __name__ == '__main__':
    while 1:
        update_mem_rrd('memory.rrd')
        time.sleep(60)

放到背景執行,會每分鐘更新數據.