diff -r 000000000000 -r 6474c204b198 python/psutil/examples/iotop.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/python/psutil/examples/iotop.py	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,159 @@
+#!/usr/bin/env python
+
+# Copyright (c) 2009, Giampaolo Rodola'. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""
+A clone of iotop (http://guichaz.free.fr/iotop/) showing real time
+disk I/O statistics.
+
+It works on Linux only (FreeBSD and OSX are missing support for IO
+counters).
+It doesn't work on Windows as curses module is required.
+
+Author: Giampaolo Rodola' <g.rodola@gmail.com>
+"""
+
+import os
+import sys
+import psutil
+if not hasattr(psutil.Process, 'get_io_counters') or os.name != 'posix':
+    sys.exit('platform not supported')
+import time
+import curses
+import atexit
+
+
+# --- curses stuff
+def tear_down():
+    win.keypad(0)
+    curses.nocbreak()
+    curses.echo()
+    curses.endwin()
+
+win = curses.initscr()
+atexit.register(tear_down)
+curses.endwin()
+lineno = 0
+
+def print_line(line, highlight=False):
+    """A thin wrapper around curses's addstr()."""
+    global lineno
+    try:
+        if highlight:
+            line += " " * (win.getmaxyx()[1] - len(line))
+            win.addstr(lineno, 0, line, curses.A_REVERSE)
+        else:
+            win.addstr(lineno, 0, line, 0)
+    except curses.error:
+        lineno = 0
+        win.refresh()
+        raise
+    else:
+        lineno += 1
+# --- /curses stuff
+
+
+def bytes2human(n):
+    """
+    >>> bytes2human(10000)
+    '9.8 K/s'
+    >>> bytes2human(100001221)
+    '95.4 M/s'
+    """
+    symbols = ('K', 'M', 'G', 'T', 'P', 'E', 'Z', 'Y')
+    prefix = {}
+    for i, s in enumerate(symbols):
+        prefix[s] = 1 << (i+1)*10
+    for s in reversed(symbols):
+        if n >= prefix[s]:
+            value = float(n) / prefix[s]
+            return '%.2f %s/s' % (value, s)
+    return '%.2f B/s' % (n)
+
+def poll(interval):
+    """Calculate IO usage by comparing IO statics before and
+    after the interval.
+    Return a tuple including all currently running processes
+    sorted by IO activity and total disks I/O activity.
+    """
+    # first get a list of all processes and disk io counters
+    procs = [p for p in psutil.process_iter()]
+    for p in procs[:]:
+        try:
+            p._before = p.get_io_counters()
+        except psutil.Error:
+            procs.remove(p)
+            continue
+    disks_before = psutil.disk_io_counters()
+
+    # sleep some time
+    time.sleep(interval)
+
+    # then retrieve the same info again
+    for p in procs[:]:
+        try:
+            p._after = p.get_io_counters()
+            p._cmdline = ' '.join(p.cmdline)
+            if not p._cmdline:
+                p._cmdline = p.name
+            p._username = p.username
+        except psutil.NoSuchProcess:
+            procs.remove(p)
+    disks_after = psutil.disk_io_counters()
+
+    # finally calculate results by comparing data before and
+    # after the interval
+    for p in procs:
+        p._read_per_sec = p._after.read_bytes - p._before.read_bytes
+        p._write_per_sec = p._after.write_bytes - p._before.write_bytes
+        p._total = p._read_per_sec + p._write_per_sec
+
+    disks_read_per_sec = disks_after.read_bytes - disks_before.read_bytes
+    disks_write_per_sec = disks_after.write_bytes - disks_before.write_bytes
+
+    # sort processes by total disk IO so that the more intensive
+    # ones get listed first
+    processes = sorted(procs, key=lambda p: p._total, reverse=True)
+
+    return (processes, disks_read_per_sec, disks_write_per_sec)
+
+
+def refresh_window(procs, disks_read, disks_write):
+    """Print results on screen by using curses."""
+    curses.endwin()
+    templ = "%-5s %-7s %11s %11s  %s"
+    win.erase()
+
+    disks_tot = "Total DISK READ: %s | Total DISK WRITE: %s" \
+                % (bytes2human(disks_read), bytes2human(disks_write))
+    print_line(disks_tot)
+
+    header = templ % ("PID", "USER", "DISK READ", "DISK WRITE", "COMMAND")
+    print_line(header, highlight=True)
+
+    for p in procs:
+        line = templ % (p.pid,
+                        p._username[:7],
+                        bytes2human(p._read_per_sec),
+                        bytes2human(p._write_per_sec),
+                        p._cmdline)
+        try:
+            print_line(line)
+        except curses.error:
+            break
+    win.refresh()
+
+def main():
+    try:
+        interval = 0
+        while 1:
+            args = poll(interval)
+            refresh_window(*args)
+            interval = 1
+    except (KeyboardInterrupt, SystemExit):
+        pass
+
+if __name__ == '__main__':
+    main()