process scheduling
时间: 2023-04-13 21:05:04 浏览: 78
进程调度是操作系统中的一个重要概念,它是指操作系统如何分配CPU时间片给不同的进程,以实现多任务处理。进程调度算法的设计可以影响操作系统的性能和响应速度,因此是操作系统设计中的一个关键问题。常见的进程调度算法包括先来先服务、短作业优先、时间片轮转等。
相关问题
Process Scheduling Algorithm Simulation实现
好的,我明白了。您的问题是如何实现进程调度算法模拟。下面是一个简单的示例代码,可以帮助您实现此功能:
```python
class Process:
def __init__(self, name, arrival_time, burst_time):
self.name = name
self.arrival_time = arrival_time
self.burst_time = burst_time
self.waiting_time = 0
self.turnaround_time = 0
self.completion_time = 0
class Scheduler:
def __init__(self, processes):
self.processes = processes
def fcfs(self):
current_time = 0
for process in self.processes:
if current_time < process.arrival_time:
current_time = process.arrival_time
process.completion_time = current_time + process.burst_time
process.turnaround_time = process.completion_time - process.arrival_time
process.waiting_time = process.turnaround_time - process.burst_time
current_time = process.completion_time
def sjf(self):
current_time = 0
remaining_processes = self.processes[:]
while remaining_processes:
next_process = min(remaining_processes, key=lambda x: x.burst_time)
remaining_processes.remove(next_process)
if current_time < next_process.arrival_time:
current_time = next_process.arrival_time
next_process.completion_time = current_time + next_process.burst_time
next_process.turnaround_time = next_process.completion_time - next_process.arrival_time
next_process.waiting_time = next_process.turnaround_time - next_process.burst_time
current_time = next_process.completion_time
def print_results(self):
for process in self.processes:
print(f"{process.name}:\tCompletion Time: {process.completion_time}\tTurnaround Time: {process.turnaround_time}\tWaiting Time: {process.waiting_time}")
```
这段代码定义了两个类:Process和Scheduler。Process类表示一个进程,其中包含进程名、到达时间、执行时间、等待时间、周转时间和完成时间等属性。Scheduler类表示一个调度器,其中包含一个进程列表,以及fcfs()和sjf()两个方法,分别实现先来先服务和短作业优先两种调度算法。print_results()方法用于打印每个进程的完成时间、周转时间和等待时间。
可以使用以下代码创建一些进程,并将它们传递给Scheduler类的实例:
```python
processes = [
Process("P1", 0, 5),
Process("P2", 1, 3),
Process("P3", 2, 8),
Process("P4", 3, 6)
]
scheduler = Scheduler(processes)
scheduler.fcfs()
scheduler.print_results()
scheduler = Scheduler(processes)
scheduler.sjf()
scheduler.print_results()
```
这将创建四个进程,并将它们传递给Scheduler类的实例。然后,使用fcfs()和sjf()方法分别模拟先来先服务和短作业优先两种调度算法,并使用print_results()方法打印结果。
希望这可以帮助您实现进程调度算法模拟。如果您有任何其他问题,请随时问我。
Write the code about Process Scheduling Algorithm Simulation in C++.The requirements are as follows:1、 Simulate the operation of the round-robin algorithm for process scheduling. 2、 Create at least 15 processes (use function fork()) and output their scheduling situation under the scheduling algorithm mentioned above and output it to the terminal to check the execution of the algorithm. 3、 The output should include the arrival time of the processes, the end time, and the average execution time
Here is an example code for Process Scheduling Algorithm Simulation using Round-Robin in C++:
```
#include <iostream>
#include <queue>
#include <ctime>
#include <unistd.h>
using namespace std;
struct Process {
int pid; // Process ID
int arrivalTime; // Arrival Time
int burstTime; // Burst Time
int remainingTime; // Remaining Time
};
int main() {
const int TIME_QUANTUM = 2;
const int NUM_PROCESSES = 15;
queue<Process> readyQueue;
Process processList[NUM_PROCESSES];
int totalExecutionTime = 0, totalWaitTime = 0, currentTime = 0;
// Generate random processes
srand(time(0));
for (int i = 0; i < NUM_PROCESSES; i++) {
processList[i].pid = i;
processList[i].arrivalTime = rand() % 10;
processList[i].burstTime = rand() % 10 + 1;
processList[i].remainingTime = processList[i].burstTime;
totalExecutionTime += processList[i].burstTime;
}
// Sort process list by arrival time
for (int i = 0; i < NUM_PROCESSES - 1; i++) {
for (int j = i + 1; j < NUM_PROCESSES; j++) {
if (processList[i].arrivalTime > processList[j].arrivalTime) {
swap(processList[i], processList[j]);
}
}
}
// Run round-robin scheduling algorithm
int currentProcessIndex = 0;
while (currentTime < totalExecutionTime) {
// Check for newly arrived processes and add them to the ready queue
while (currentProcessIndex < NUM_PROCESSES && processList[currentProcessIndex].arrivalTime <= currentTime) {
readyQueue.push(processList[currentProcessIndex]);
currentProcessIndex++;
}
if (!readyQueue.empty()) {
// Get the next process from the ready queue
Process currentProcess = readyQueue.front();
readyQueue.pop();
// Execute the process for the time quantum or until it finishes
int executionTime = min(TIME_QUANTUM, currentProcess.remainingTime);
currentProcess.remainingTime -= executionTime;
currentTime += executionTime;
// Check if the process has finished
if (currentProcess.remainingTime == 0) {
cout << "Process " << currentProcess.pid << " finished at time " << currentTime << endl;
totalWaitTime += currentTime - currentProcess.arrivalTime - currentProcess.burstTime;
} else {
// Put the process back in the ready queue
readyQueue.push(currentProcess);
}
} else {
// No processes in the ready queue, advance time
currentTime++;
}
}
// Calculate average execution time and output results
double averageExecutionTime = (double)(totalExecutionTime) / NUM_PROCESSES;
double averageWaitTime = (double)(totalWaitTime) / NUM_PROCESSES;
cout << "Average Execution Time: " << averageExecutionTime << endl;
cout << "Average Wait Time: " << averageWaitTime << endl;
return 0;
}
```
This code generates 15 random processes with arrival time and burst time. It then sorts the process list by arrival time and runs the round-robin scheduling algorithm with a time quantum of 2. The program outputs the process ID and finish time for each process and calculates the average execution time and average wait time.