feat(ex_13_1): update for timeslice

ludics · Oct 28, 2023 · 436aa37 · 436aa37
1 parent 6dda145
commit 436aa37
Show file tree

Hide file tree

Showing 3 changed files with 37 additions and 19 deletions.
diff --git a/code/exercises/ex_13_1/sched.c b/code/exercises/ex_13_1/sched.c
@@ -32,6 +32,7 @@ uint32_t task_timeslice[MAX_TASKS];
  * _current is used to point to the context of current task
  */
 static int _current = -1;
+static int _cur_timeslice = 0;
 
 extern void os_schedule();
 
@@ -54,11 +55,7 @@ void sched_init()
 	}
 }
 
-/*
- * implment a simple cycle FIFO schedular
- */
-void schedule()
-{
+int find_next_task_id() {
 	// 先扫描获取最高优先级
 	int highest_priority = 0xff;
 	for (int i = 0; i < MAX_TASKS; i++) {
@@ -85,13 +82,34 @@ void schedule()
 			}
 		}
 	}
+	return next_task_id;
+}
+
+/*
+ * implment a simple cycle FIFO schedular
+ */
+void schedule()
+{
+	int next_task_id = find_next_task_id();
+	// 没有可调度的任务
 	if (next_task_id == -1) {
-		// 没有可调度的任务
 		printf("no schedulable task!\n");
 		switch_to(&ctx_os);
 	}
+	// 检查下个任务的优先级是否比当前任务高，如果高则切换
+	// 如果优先级相同，则检查当前任务的时间片是否用完
+	if (_current == -1 || task_status[_current] == TASK_EXITED) {
+		_current = next_task_id;
+		_cur_timeslice = 1;
+	} else if (task_priorities[next_task_id] < task_priorities[_current] ||
+			(task_priorities[next_task_id] == task_priorities[_current] &&
+			 task_timeslice[_current] <= _cur_timeslice )) {
+		_current = next_task_id;
+		_cur_timeslice = 1;
+	} else {
+		_cur_timeslice++;
+	}
 	// 切换到下一个任务
-	_current = next_task_id;
 	struct context *next = &(ctx_tasks[_current]);
 	task_status[_current] = TASK_RUNNING;
 	switch_to(next);

diff --git a/code/exercises/ex_13_1/timer.c b/code/exercises/ex_13_1/timer.c
@@ -23,18 +23,18 @@ void timer_init()
 	 * On reset, mtime is cleared to zero, but the mtimecmp registers 
 	 * are not reset. So we have to init the mtimecmp manually.
 	 */
-	timer_load(TIMER_INTERVAL_MS * 500);
+	timer_load(TIMER_INTERVAL_MS * 300);
 
 	/* enable machine-mode timer interrupts. */
 	w_mie(r_mie() | MIE_MTIE);
 }
 
-void timer_handler() 
+void timer_handler()
 {
 	_tick++;
 	printf("tick: %d\n", _tick);
 
-	timer_load(TIMER_INTERVAL_MS * 1000);
+	timer_load(TIMER_INTERVAL_MS * 300);
 
 	schedule();
 }
diff --git a/code/exercises/ex_13_1/user.c b/code/exercises/ex_13_1/user.c
@@ -27,7 +27,7 @@ void user_task(void* param)
 {
 	int id = (int) param;
 	printf("Task %d: Created!\n", id);
-	int iter_cnt = id / 1000 + 5;
+	int iter_cnt = id / 1000 + 10;
 	while (1) {
 		printf("Task %d: Running...\n", id);
 		task_delay(DELAY);
@@ -44,13 +44,13 @@ void os_main(void)
 {
 	// task_create(user_task0, NULL, 255, 0);
 	// task_create(user_task1, NULL, 255, 0);
-	task_create(user_task, (void *)3000, 0, 0);
-	task_create(user_task, (void *)8003, 3, 0);
-	task_create(user_task, (void *)2005, 5, 0);
-	task_create(user_task, (void *)5000, 0, 0);
-	task_create(user_task, (void *)9004, 4, 0);
-	task_create(user_task, (void *)6001, 1, 0);
-	task_create(user_task, (void *)7002, 2, 0);
-	task_create(user_task, (void *)4000, 0, 0);
+	task_create(user_task, (void *)3000, 0, 2);
+	task_create(user_task, (void *)8003, 3, 2);
+	task_create(user_task, (void *)2003, 3, 3);
+	task_create(user_task, (void *)5000, 0, 3);
+	task_create(user_task, (void *)9003, 3, 4);
+	task_create(user_task, (void *)6001, 1, 3);
+	task_create(user_task, (void *)7001, 1, 2);
+	task_create(user_task, (void *)4000, 0, 4);
 }