thread scheduling

Hi All,
How the threads are scheduled in Linux?
I have written one program. I have created two threads. I am passing two variables for scheduling policies. One is having FIFO and other is having RR. I am passing first variable when creating first thread and second variable when creating second thread?
HOw these two thread will be scheduled?

Hi,
I understand why you want to know, but the real answer is you can't know how they are scheduled.
Any software that relies on or tries to predict which thread runs first, and when, is inherently broken by design.
You have to use external means to synchronize your threads in a manner consistent with your software's design.
I know everyone that starts learning to write threaded code tries to do this, but it always "mostly" or "just barely" works "most of the time".
When you move your software to a different platform with a different kernel, or to a computer with multiple processors, then it mysteriously stops working.

O.K. with root permission (get sure) you can change the scheduling of "Linux" the Kernel to FIFO or RR or...
If a process (root) changes to FIFO than that process can be sure that no other process (just IRQs also the Timer for scheduling) is running at this runtime (DOS Real Mode). So no mouse is moving and no key responds no signal is emit no X-server can work and so on.
With other scheduling the Processors time is shared with all threads. So Linux looks for the next thread in the table and give its some time also the kernel gets time like this.So if one process change to FIFO than that Process has to look for the other processes that are needed. So only functions can be (should be) called at this time, anything that returns surly!!! or can handle FIFO mode - no process can be killed in this scope! So this process have to make sure to read from the keyboard (kernel function) some time that the user have a possibility to quit that process. And at the End this process has also to make sure that the scheduling is restored to RR or whatever the scheduling was before. Other scheduling doesn't mather or you won't feel a big different.

So if your FIFO process is to get some time than it happens... only if that process returns the others can continue.