Rescheduling: kernel calls

If the rescheduling is caused by a thread issuing a kernel call, the rescheduling is done immediately and can be considered asynchronous to the timer and other interrupts.

For example, above we called sleep(10);. This C library function is eventually translated into a kernel call. At that point, the kernel made a rescheduling decision to move your thread from the RUNNING state, and then schedule another thread that was READY.

There are many kernel calls that cause a process to be rescheduled. Most of them are fairly obvious. Here are a few:

• timer functions (e.g., sleep())
• messaging functions (e.g., MsgSendv())
• thread primitives, (e.g., pthread_cancel(), pthread_join())