Enable KSM on default kernel

[samuel wang]

http://en.wikipedia.org/wiki/Kernel_SamePage_Merging_%28KSM%29

As described in Wiki above, KSM would prove valuable to our Dns's meager 64mb of ram :P Swap is always there...but prefereably swap shouldn't be used so as to let the disk spin down.

Would it be a good idea to enable it by default on the kernel ? Last i tried, i did see more free RAM on the system, allowing me to do more things. ( torrent, mpd and ftp )
 CPU usage penalty wasn't much of a problem.


More details of KSM
http://www.linux-kvm.com/content/using-ksm-kernel-samepage-merging-kvm

[Joao Cardoso]

On Friday, March 22, 2013 8:00:44 AM UTC, samuel wang wrote:

http://en.wikipedia.org/wiki/Kernel_SamePage_Merging_%28KSM%29

As described in Wiki above, KSM would prove valuable to our Dns's meager 64mb of ram :P Swap is always there...but prefereably swap shouldn't be used so as to let the disk spin down.

Would it be a good idea to enable it by default on the kernel ? Last i tried, i did see more free RAM on the system, allowing me to do more things. ( torrent, mpd and ftp )

From my readings, I understand that KSM is useful on systems running multiple virtualized hosts (of the same kind).

linux has since its beginning support for code and data sharing among processes, and KSM extends that concept to virtualized hosts that are running the same host OS.

Although some articles says that it is also beneficial on standard usage, I don't understand why and how, and I found no reports that support such claims with data. For me, that's just a myth.

If you can find articles that support those claims with real data, please let me know.

 

 CPU usage penalty wasn't much of a problem.

But until I conceptually understand why would it help, I will not waste a single CPU cycle on it ;-)

Added: or I see that it becomes standard practice among low end desktop or appliance boxes.