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 take your thread off of the READY queue for that priority, 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: