How to prevent other processes from being scheduled

Hi, everyone

How can I prevent other processes than my specific application from 
being scheduled?

I thougt that when my program being started, it would invokes the kernel 
to do "local_irq_disable()"
and when it ended, it would call "local_irq_enable()" in order that 
scheduler not working
when my specific program runs.

But i seems do not work as I likes.

Please give me some hints what i should do...

Thanks in advance.

J.Hwan Kim