iostat.py

#!/usr/bin/env python
# coding: utf-8
# file   : iostat.py
# author : freelingchang
# 修改使支持2.6


import os
import re
import sys
import time
import commands
from datetime import datetime
import copy
import thread
import logging
from pprint import pprint
import pickle

DISK = 'sda'
logFile = '/dev/shm/iostst.log'
stateFile = '/sys/block/' + DISK + '/stat'
logPath = os.path.split(os.path.realpath(__file__))[0]


def getStateContent(statFile):
    f = open(stateFile, 'r')
    stateContent = f.read()
    f.close
    return stateContent


def tonum(n):
    if type(n) == type(''):
        if n.isdigit():
            return int(n)
        return n


def writeState(stateDict):
    f = open(logFile, 'w')
    pickle.dump(stateDict, f)
    f.close()


def readLastState(stateDict):
    global logFile
    if not os.path.exists('/dev/shm'):
        logFile = logPath + '/iostat.log'
    if not os.path.isfile(logFile):
        writeState(stateDict)
        return stateDict
    st = os.stat(logFile)
    mode, ino, dev, nlink, uid, gid, size, atime, mtime, ctime = st
    if size == 0:
        writeState(stateDict)
        return stateDict
    f = open(logFile, 'r')
    # print(f.read());
    lastStateDict = pickle.load(f)
    f.close()
    writeState(stateDict)
    return lastStateDict


def setStateDict(line):
    d = {}
    r_ios, r_merges, r_sec, r_ticks, w_ios, w_merges, w_sec, w_ticks, ios_pgr, tot_ticks, rq_ticks = line.split()
    del line
    for k in locals().items():
        #    print k[1]
        d[k[0]] = tonum(k[1])
    #d = {k: tonum(v) for k, v in locals().items() }
    d['ts'] = time.time()
    return d
#:rrqm/s   : The number of read requests merged per second that were queued to the device.    #( rd_merges[1] - rd_merges[0] )
#:wrqm/s   :
#:r/s      : The number of read requests that were issued to the device per second.           #(rd_ios[1] - rd_ios[0]) #:w/s      : #:rkB/s    : The number of kilobytes read from the device per second.                         #( rd_sectors[1] - rd_sectors[0] ) * sector_size
#:wkB/s    :

#:avgrq-sz : (平均请求大小)The average size **in sectors** of the requests that were issued to the device.
    #( ( rd_sectors[1] - rd_sectors[0] ) + ( wr_sectors[1] - wr_sectors[0] ) ) / (rd_ios[1] - rd_ios[0]) + (wr_ios[1] - wr_ios[0])
#:avgqu-sz : The average queue length of the requests that were issued to the device.
    # 这不是ios_pgr, 而是: (rq_ticks[1] - rq_ticks[0]) / 1000 这是什么原理.

#:await    : (等待时间)The average time (in milliseconds) for I/O requests issued to the  device  to  be  served
    #( ( rd_ticks[1] - rd_ticks[0] ) + ( wr_ticks[1] - wr_ticks[0] ) ) / (rd_ios[1] - rd_ios[0]) + (wr_ios[1] - wr_ios[0])
#:svctm    : (服务时间)The average service time (in milliseconds) for I/O requests that were issued to the device.  (和上一个很像)
    #util/(rd_ios[1] - rd_ios[0]) + (wr_ios[1] - wr_ios[0])
#:util     : Percentage  of  CPU time during which I/O requests were issued to the device
    #(tot_ticks[1] - tot_ticks[0]) / 1000 * 100


def calc(last, curr):
    SECTOR_SIZE = 512
    stat = {}

    def diff(field):
        return (curr[field] - last[field]) / (curr["ts"] - last["ts"])

    stat['rrqm/s'] = diff('r_merges')
    stat['wrqm/s'] = diff('w_merges')
    stat['r/s'] = diff('r_ios')
    stat['w/s'] = diff('w_ios')
    stat['rkB/s'] = diff('r_sec') * SECTOR_SIZE / 1024
    stat['wkB/s'] = diff('w_sec') * SECTOR_SIZE / 1024

    stat['avqqu-sz'] = diff('rq_ticks') / 1000
    # print 'tot_ticks', curr['tot_ticks'], last['tot_ticks']
    stat['util'] = diff('tot_ticks') / 10  # ???

    if diff('r_ios') + diff('w_ios') > 0:
        stat['avgrq-sz'] = (diff('r_sec') + diff('w_sec')) / \
            (diff('r_ios') + diff('w_ios'))
        stat['await'] = (diff('r_ticks') + diff('w_ticks')) / \
            (diff('r_ios') + diff('w_ios'))
        stat['svctm'] = diff('tot_ticks') / (diff('r_ios') + diff('w_ios'))
    else:
        stat['avgrq-sz'] = 0
        stat['await'] = 0
        stat['svctm'] = 0

    return stat


def printstat(stat):
    print datetime.now(),
    for k, v in stat.items():
        print '%s: %.2f' % (k, float(v)),
    print ''


def check():
    stateContent = getStateContent(stateFile)
    nowStateDict = setStateDict(stateContent)
    lastStateDict = readLastState(nowStateDict)
    stat = calc(lastStateDict, nowStateDict)
    printstat(stat)

if __name__ == "__main__":
    check()

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