• Accounting: Currently running process is charged a tick of CPU time,
• Updating time: Global kernel time value (jiffies) is updated,
• Timers: Expired timers (previously set by the kernel or user tasks) are executed,
• Preemption and scheduling: Currently running task is preempted if it exceeded its scheduling time quanta or another higher priority task has became runnable,
• Bottom half handlers and workqueue items: Long-lived interrupt processing and delayed work items are checked and executed.