Hi Friend,
I can only give you idea regarding this. It may increase the server load though. My idea uses node.js.
What you have to do is :
1. Create a GET request (all the browsers create it while requesting a webpage), in node.js
2. Put the url as http://localhost/criticalscript.php (This url is a demo only). You actually have to call your own script that you want to run every 12 sec.
3. Create a timeout function in node.js and call it every 12 sec to request that script every 12 sec.
4. What happens is, the script is run on your server every 12 sec.
The point though is, you must have root access of the server to do so (if I am not wrong). Yet I am not 100% sure about this.
For further ideas Please visit
this link.
Hope it helped :) Please rate my answer and mark as solved if it solved your problem :)
With Regards
Tushar Srivastava