#!/usr/bin/env python
# -*- encoding: UTF-8 -*-
#
# ksm
#
# Plugin to monitor ksm - Kernel Samepage Merging.
#
# Author: Markus Heberling <markus@tisoft.de>
#
# v1.0 2011-04-05 - First version
#
# Usage: place in /etc/munin/plugins/ (or link it there using ln -s)
#
# Parameters understood:
#
#       config   (required)
#       autoconf (optional - used by munin-config)
#
# Magic markers - optional - used by installation scripts and
# munin-config:
#
#%# capabilities=autoconf suggest
#%# family=auto

###########################################################
category = 'system' # 'upgrades'
title = 'Kernel Samepage Merging' # 'Upgradeable packages'
###########################################################

import os
import sys
import warnings

def autoconf():
    if os.path.exists('/sys/kernel/mm/ksm/run'):
        for line in open('/sys/kernel/mm/ksm/run'):
            if line.strip() == '1':
               print 'yes'
               sys.exit(0)
    print 'no (/sys/kernel/mm/ksm/run must be present and value must be 1)'
    sys.exit(0)

def suggest():
    print 'pages_absolute'
    print 'pages_relative'
    print 'full_scans'
    sys.exit(0)


def config():
    if('ksm_pages_absolute' in sys.argv[0]): 
        print 'graph_category %s' % (category)
        print 'graph_title %s Pages Absolute' % (title)
        print 'graph_order pages_unshared pages_volatile pages_shared pages_sharing'
        print 'pages_shared.info how many shared pages are being used'
        print 'pages_sharing.info how many more sites are sharing them i.e. how much saved'
        print 'pages_unshared.info how many pages unique but repeatedly checked for merging'
        print 'pages_volatile.info how many pages changing too fast to be placed in a tree'
        print 'pages_shared.label pages_shared'
        print 'pages_sharing.label pages_sharing'
        print 'pages_unshared.label pages_unshared'
        print 'pages_volatile.label pages_volatile'
        print 'pages_shared.draw AREASTACK'
        print 'pages_sharing.draw AREASTACK'
        print 'pages_unshared.draw AREASTACK'
        print 'pages_volatile.draw AREASTACK'
    elif('ksm_pages_relative' in sys.argv[0]):
        print 'graph_category %s' % (category)
        print 'graph_title %s Pages Relative' % (title)
        print 'pages_sharing_shared.info ratio of sharing to shared pages'
        print 'pages_unshared_sharing.info ratio of unshared to sharing pages'
        print 'pages_sharing_shared.label pages_sharing_shared'
        print 'pages_unshared_sharing.label pages_unshared_sharing'
        print 'pages_sharing_shared.cdef pages_sharing_shared,100,*'
        print 'pages_unshared_sharing.cdef pages_unshared_sharing,100,*'
    elif('ksm_full_scans' in sys.argv[0]):
        print 'graph_category %s' % (category)
        print 'graph_title %s Full Scans' % (title)
        print 'full_scans.info how many times all mergeable areas have been scanned'
        print 'full_scans.label full_scans'
    sys.exit(0)

if len(sys.argv) > 1:
    if sys.argv[1] == 'autoconf':
        autoconf()
    elif sys.argv[1] == 'config':
        config()
    elif sys.argv[1] == 'suggest':
        suggest()
    elif sys.argv[1]:
        print('unknown argument "' + sys.argv[1] + '"')
        sys.exit(1)

pages_shared=int(open('/sys/kernel/mm/ksm/pages_shared').read())
pages_sharing=int(open('/sys/kernel/mm/ksm/pages_sharing').read())
pages_unshared=int(open('/sys/kernel/mm/ksm/pages_unshared').read())
pages_volatile=int(open('/sys/kernel/mm/ksm/pages_volatile').read())
full_scans=int(open('/sys/kernel/mm/ksm/full_scans').read())

if('ksm_pages_absolute' in sys.argv[0]): 
    print 'pages_shared.value %i' % pages_shared
    print 'pages_sharing.value %i' % pages_sharing
    print 'pages_unshared.value %i' % pages_unshared
    print 'pages_volatile.value %i' % pages_volatile
elif('ksm_pages_relative' in sys.argv[0]): 
    print 'pages_sharing_shared.value %f' % (float(pages_sharing)/float(pages_shared) if pages_shared>0 else 0)
    print 'pages_unshared_sharing.value %f' % (float(pages_unshared)/float(pages_sharing) if pages_sharing>0 else 0)
elif('ksm_full_scans' in sys.argv[0]): 
    print 'full_scans.value %i' % full_scans