global market access

List of contents of this article:

• 1,global market access Analysis of Several Process Scheduling Algorithms
• 2, Operating system process scheduling problem
• 3, About the time slice rotation scheduling algorithm in the operating system! Please help me answer!
• 4, What are the two ways of process scheduling?

Analysis of several process scheduling algorithms

Scheduling algorithms in interactive systems, representing scheduling algorithms include: rotation scheduling, priority scheduling, multi-level queue, shortest process priority, guaranteed scheduling, Lottery scheduling, fair sharing scheduling. The scheduling algorithm in the real-time system represents the scheduling algorithm: rate monotonous scheduling, the earliest final time limit priority scheduling.

First-come, first-served: It is the simplest scheduling algorithm, which is scheduled in order of priority. Rotation method: It is to make the waiting time of each process in the ready queue proportional to the time to enjoy the service.

Multi-level feedback queue scheduling algorithm Implementation idea: set multiple ready queues, set different priorities for each queue, and the priority is reduced once.The time slices in each queue are different, and the time pieces decrease in order.

Short job/process priority scheduling algorithm: select the job/process that has arrived and has the shortest running time each time.. Because process 1 is the first to reach, and there are no other threads at this time, process 1 is served first.

Operating system process scheduling problem

Time slice influencing factors: system response time, the number of processes in the ready queue and the processing capacity of the system will not lead to hunger Preemptive multi-level feedback queue scheduling algorithm Implementation idea: set up multiple ready queues for each The queue sets different priorities, and the priority decreases once.

In the real-time system, the general task time is relatively short, and the scheduler needs to complete all processes before the deadline. For periodic events, if the cycle of the event is, and the event processing time (need to occupy the time of the CPU) is, it can only be scheduled.

A process changes the scheduling policy or lowers its own priority (such as the nice command) by executing system calls, thus causing immediate scheduling.Scheduling algorithm The algorithm of process scheduling should be relatively simple in order to reduce the system overhead of frequent scheduling.

Design process control fast, process queue structure (including: ready queue, waiting queue, running queue) and other necessary data structures. 2: Simulate the function of operating system process scheduling, write process scheduling program, simulate processor dispatch program, process waiting function and process wake-up function.

About the time slice rotation scheduling algorithm in the operating system! Please help me answer!

First start the A process with an arrival time of 0, the second time slice, or A, the third start the B process, the fourth, return to A, the fifth start C..

Time slice rotation scheduling algorithm (RR): Give each process a fixed execution time, let the process execute in the unit time slice according to the order of process arrival, and schedule the next process to execute after the execution is completed. The time slice rotation scheduling does not consider the waiting time and execution time of the process, which belongs to Semptive dispatch.

Assign a needtime to each process when the system is initialized, and all processes are arranged into a queue in order of needtime from small to large. 2) Take the team leader process and put it into operation.

The time slice rotation method is mainly a scheduling algorithm used in the time division system. The basic idea of the time slice rotation method is to divide the processing time of the CPU into time pieces, and the processes in the ready queue take turns to run a time piece.

What are the two ways of process scheduling?

There are two types of scheduling methods for the process: non-deprivation scheduling (non-preemption) and deprivation scheduling (preemption). Non-preemptive: Only the process is allowed to actively abandon the processor. For example, the process run ends, the abnormal ends or actively requests I/O blocking.

There are non-deprivation methods and deprivation methods for process scheduling. Non-deprivation method: Once the dispatcher assigns the processor to a process, it keeps it running until the process is completed or an event is blocked, and the processor is assigned to another process.

There are two basic ways of process scheduling: non-deprivation method. Once the allocation program is processedAfter the machine is assigned to a process, it is allowed to run until the process is completed or blocked by an event, and the processor is assigned to another process.