#!/usr/bin/python

# Monitoring per-process disk I/O activity

# written by http://www.vpsee.com 

import sys, os, time, signal, re

class DiskIO:

    def __init__(self, pname=None, pid=None, reads=0, writes=0):

        self.pname = pname

        self.pid = pid

        self.reads = 0

        self.writes = 0

def main():

    argc = len(sys.argv)

    if argc != 1:

        print "usage: ./iotop"

        sys.exit(0)

    if os.getuid() != 0:

        print "must be run as root"

        sys.exit(0)

    signal.signal(signal.SIGINT, signal_handler)

    os.system('echo 1 > /proc/sys/vm/block_dump')

    print "TASK              PID       READ      WRITE"

    while True:

        os.system('dmesg -c > /tmp/diskio.log')

        l = []

        f = open('/tmp/diskio.log', 'r')

        line = f.readline()

        while line:

            m = re.match(\

                '^(\S+)\((\d+)\): (READ|WRITE) block (\d+) on (\S+)', line)

            if m != None:

                if not l:

                    l.append(DiskIO(m.group(1), m.group(2)))

                    line = f.readline()

                    continue

                found = False

                for item in l:

                    if item.pid == m.group(2):

                        found = True

                        if m.group(3) == "READ":

                            item.reads = item.reads + 1

                        elif m.group(3) == "WRITE":

                            item.writes = item.writes + 1

                if not found:

                    l.append(DiskIO(m.group(1), m.group(2)))

            line = f.readline()

        time.sleep(1)

        for item in l:

            print "%-10s %10s %10d %10d" % \

                (item.pname, item.pid, item.reads, item.writes)

def signal_handler(signal, frame):

    os.system('echo 0 > /proc/sys/vm/block_dump')

    sys.exit(0)

if __name__=="__main__":

    main()