Simple bash script to calculate ksm stats in MB

ksm_stats_in_MB

#!/bin/bash

if [ "$1" != "" ]; then
    echo "
    ----------------------------------------------------------------------------
    http://www.kernel.org/doc/Documentation/vm/ksm.txt :

    The effectiveness of KSM and MADV_MERGEABLE is shown in /sys/kernel/mm/ksm/:

    pages_shared     - how many shared pages are being used
    pages_sharing    - how many more sites are sharing them i.e. how much saved
    pages_unshared   - how many pages unique but repeatedly checked for merging
    pages_volatile   - how many pages changing too fast to be placed in a tree
    full_scans       - how many times all mergeable areas have been scanned

    A high ratio of pages_sharing to pages_shared indicates good sharing, but
    a high ratio of pages_unshared to pages_sharing indicates wasted effort.
    pages_volatile embraces several different kinds of activity, but a high
    proportion there would also indicate poor use of madvise MADV_MERGEABLE.
    ----------------------------------------------------------------------------
    "
fi;

pages_shared=`cat /sys/kernel/mm/ksm/pages_shared`;
pages_sharing=`cat /sys/kernel/mm/ksm/pages_sharing`;
pages_unshared=`cat /sys/kernel/mm/ksm/pages_unshared`;
pages_volatile=`cat /sys/kernel/mm/ksm/pages_volatile`;
page_size=`getconf PAGESIZE`;

ratio_sharing_to_shared=$(echo "scale=2;$pages_sharing / $pages_shared"|bc);
ratio_unshared_to_sharing=$(echo "scale=2;$pages_unshared / $pages_sharing"|bc);
saved=$(echo "scale=0;$pages_sharing * $page_size / 1024 / 1024"|bc);


printf "%10s %10s %10s %10s %10s:%-8s %10s:%-8s %10s\n" "Shared" "Sharing" "Unshared" "Volatile" "Sharing" "Shared" "Unshared" "Sharing" "Saved (MB)";
printf "%10d %10d %10d %10d %10.1f:%-8s %10.1f:%-8s %10d\n" $pages_shared $pages_sharing $pages_unshared $pages_volatile $ratio_sharing_to_shared "1" $ratio_unshared_to_sharing "1" $saved;