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