进程调度算法edf和rms代码改进

EDF（Earliest Deadline First）和RMS（Rate-Monotonic Scheduling）是常用的实时系统进程调度算法，下面是它们的代码改进示例：

EDF算法改进：

原始代码：

void edf_scheduler() {
    while (1) {
        int min_deadline = INT_MAX;
        int next_process = -1;
        for (int i = 0; i < num_processes; i++) {
            if (!processes[i].completed && processes[i].deadline < min_deadline) {
                min_deadline = processes[i].deadline;
                next_process = i;
            }
        }
        if (next_process == -1) {
            break;
        }
        execute_process(next_process);
    }
}

改进后的代码：

void edf_scheduler() {
    while (1) {
        int min_deadline = INT_MAX;
        int next_process = -1;
        for (int i = 0; i < num_processes; i++) {
            if (!processes[i].completed && processes[i].deadline < min_deadline) {
                if (processes[i].arrival_time <= current_time) { // 添加判断进程是否到达
                    min_deadline = processes[i].deadline;
                    next_process = i;
                }
            }
        }
        if (next_process == -1) {
            break;
        }
        execute_process(next_process);
    }
}

改进后的代码增加了一个判断，判断进程是否到达，如果未到达就不会被调度执行。这样可以避免出现进程还未到达就被调度执行的情况。

RMS算法改进：

原始代码：

void rms_scheduler() {
    while (1) {
        int min_period = INT_MAX;
        int next_process = -1;
        for (int i = 0; i < num_processes; i++) {
            if (!processes[i].completed && processes[i].period < min_period) {
                min_period = processes[i].period;
                next_process = i;
            }
        }
        if (next_process == -1) {
            break;
        }
        execute_process(next_process);
        processes[next_process].executed++;
        if (processes[next_process].executed == processes[next_process].execution_time) {
            processes[next_process].completed = true;
        }
    }
}

改进后的代码：

void rms_scheduler() {
    while (1) {
        int min_period = INT_MAX;
        int next_process = -1;
        for (int i = 0; i < num_processes; i++) {
            if (!processes[i].completed && processes[i].period < min_period) {
                if (processes[i].arrival_time <= current_time) { // 添加判断进程是否到达
                    min_period = processes[i].period;
                    next_process = i;
                }
            }
        }
        if (next_process == -1) {
            break;
        }
        execute_process(next_process);
        processes[next_process].executed++;
        if (processes[next_process].executed == processes[next_process].execution_time) {
            processes[next_process].completed = true;
        }
    }
}

改进后的代码同样增加了一个判断，判断进程是否到达。如果未到达就不会被调度执行。这样可以避免出现进程还未到达就被调度执行的情况。