load balancing scheduler on linux

Hi, Can somebody give pointers to the load balancing scheduler on Linux. I hope this is the default scheduler which is used on most of the linux systems on SMP environment. I would like to know how the scheduler takes a decision to migrate some of the processes to the another core? I have a scenario like below: If CORE0 is running per say 2 threads which can be handled by CORE0 itself ( by running at higher frequencies ) without enabling the CORE1 ( put into some low power mode ). How the scheduler takes this kind of decision intelligently!!! -- Regards, Murali N