Timer setting, to help us get an application execution time. You can help us observe the experiment is complex algorithm's time degree Practice how to write kernel call time measurement capabilities for measuring and precision timing applications, through this experiment: You can learn more about timing mechanism within Linux and the data results, and how to access the kernel of the control data from the user space of time. Principle: Before the main action of each user process executing a set time, after the main action is completed, the acquisition time, and so has been the main action of the execution time,