关于vxworks轮转调度

[freeman11me]

下面是《vxworks与tornado》的例子：
#define PRIORITY 50
#define TIMESFLICE (float)sysClkRateGet()/100
void sched(void)
{
int taskIdOne, taskIdTwo, taskIdThree;
int i, j;

if(kernelTimeSlice(TIMESLICE) == OK)
printf("\n\n\n\n\t\t\tTIMESLICE = %f secondes\n\n\n", TIMESLICE/60);
else
printf("\n\n\n\n\t\t\tTIMESLICE SET ERROR!\n\n\n");

if((taskIdOne =
taskSpawn("task1", PRIORITY, 0x100, 2000, taskOne,
0,0,0,0,0,0,0,0,0,0)) == ERROR);
printf("taskSpawn taskOne failed\n");

if((taskIdTwo =
taskSpawn("task2", PRIORITY, 0x100, 2000, taskTwo,
0,0,0,0,0,0,0,0,0,0)) == ERROR);
printf("taskSpawn taskTwo failed\n");

if((taskIdThree =
taskSpawn("task3", PRIORITY, 0x100, 2000, taskThree,
0,0,0,0,0,0,0,0,0,0)) == ERROR);
printf("taskSpawn taskThree failed\n");


for(i = 0;i < ITER1;i++)
{
for(j = 0; j < ITER2; j++)
logMsg("\n", 0, 0, 0, 0, 0, 0);
for(j = 0; j < LONG_TIME; j++);
}
}
sched的优先级为100,taskSpawn出来的任务的优先级都是50，实现轮转调度，发现放在sched代码后的循环语句还是在新建的三个任务前运行。
轮转调度不是先运行高优先级的任务吗？以为sched中的循环语句应该在所有新建任务完成后在执行的，请高手指教。

[土豆]

有两个问题：
1.你怎么确定“放在sched代码后的循环语句还是在新建的三个任务前运行”？是在你创建的task里面加打印?

2.logMsg本身通过消息队列实现，也就是说对logMsg的调用本身就是通过向另外一个任务tLogTask发送消息，通过tLogTask输出到屏幕的。


有时侯看到的并不是真实的。

[erigido]

taskSpawn就是一个任务切换点，肯定是进行了切换。我也有同样的问题，task里面里面做什么了？

上面高手说的没错，logMsg为了保证在中断中可以调用，都是同一发给tLogTask任务来进行输出的。

最简单的方式，可以在内存中记录当前的cputick值看看。

[freeman11me]

这个代码运行起来一直没有看到理论中的那种task1,task2,task3轮流运行一段时间的效果：

#include "vxWorks.h"
#include "taskLib.h"
#include "kernelLib.h"
#include "sysLib.h"
#include "logLib.h"

void taskOne(void);
void taskTwo(void);
void taskThree(void);

#define ITER1 5
#define ITER2 10
#define PRIORITY 50
#define TIMESLICE (float)sysClkRateGet()/100
#define LONG_TIME 1000000

void sched(void)
{
	int taskIdOne, taskIdTwo, taskIdThree;
       int i, j;

	if(kernelTimeSlice(TIMESLICE) == OK)
		printf("\n\n\n\n\t\t\tTIMESLICE = %f secondes\n\n\n", TIMESLICE/60);
	else
		printf("\n\n\n\n\t\t\tTIMESLICE SET ERROR!\n\n\n");

	if((taskIdOne =
		taskSpawn("task1", PRIORITY, 0x100, 2000, taskOne,
		   0,0,0,0,0,0,0,0,0,0)) == ERROR);
	      printf("taskSpawn taskOne failed\n");
		  
	if((taskIdTwo =
		taskSpawn("task2", PRIORITY, 0x100, 2000, taskTwo,
		   0,0,0,0,0,0,0,0,0,0)) == ERROR);
	      printf("taskSpawn taskTwo failed\n");

	if((taskIdThree =
		taskSpawn("task3", PRIORITY, 0x100, 2000, taskThree,
		   0,0,0,0,0,0,0,0,0,0)) == ERROR);
	      printf("taskSpawn taskThree failed\n");

	  
}

void taskOne(void)
{
	int i, j;
	for(i = 0;i < ITER1;i++)
	{
		for(j = 0; j < ITER2; j++)
			logMsg("\n", 0, 0, 0, 0, 0, 0);
		for(j = 0; j < LONG_TIME; j++);
	}
}

void taskTwo(void)
{
	int i, j;
	for(i = 0;i < ITER1;i++)
	{
		for(j = 0; j < ITER2; j++)
			logMsg("\n", 0, 0, 0, 0, 0, 0);
		for(j = 0; j < LONG_TIME; j++);
	}
}

void taskThree(void)
{
	int i, j;
	for(i = 0;i < ITER1;i++)
	{
		for(j = 0; j < ITER2; j++)
			logMsg("\n", 0, 0, 0, 0, 0, 0);
		for(j = 0; j < LONG_TIME; j++);
	}
}

运行结果如下：

			TIMESLICE = 0.010000 secondes


taskSpawn taskOne failed
taskSpawn taskTwo failed
taskSpawn taskThree failed
0x3868de8 (task1): 
0x3868de8 (task1): 
0x3868de8 (task1): 
0x3868de8 (task1): 
0x3868de8 (task1): 
0x3868de8 (task1): 
0x3868de8 (task1): 
0x3868de8 (task1): 
0x3868de8 (task1): 
0x3868de8 (task1): 
0x3868de8 (task1): 
0x3868de8 (task1): 
0x3868de8 (task1): 
0x3868de8 (task1): 
0x3868de8 (task1): 
0x3868de8 (task1): 
0x3868de8 (task1): 
0x3868de8 (task1): 
0x3868de8 (task1): 
0x3868de8 (task1): 
0x3868de8 (task1): 
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0x3868de8 (task1): 
0x3868de8 (task1): 
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0x3868de8 (task1): 
0x3868de8 (task1): 
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0x3868de8 (task1): 
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0x3868de8 (task1): 
0x3868de8 (task1): 
0x3868de8 (task1): 
0x3868de8 (task1): 
0x3868de8 (task1): 
0x3868de8 (task1): 
0x3868de8 (task1): 
0x3868de8 (task1): 
0x3868de8 (task1): 
0x3868de8 (task1): 
0x3868de8 (task1): 
0x3868de8 (task1): 
0x3865268 (task2): 
0x3865268 (task2): 
0x3865268 (task2): 
0x3865268 (task2): 
0x3865268 (task2): 
0x3865268 (task2): 
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0x3865268 (task2): 
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0x3865268 (task2): 
0x3865268 (task2): 
0x3865268 (task2): 
0x3865268 (task2): 
0x3865268 (task2): 
0x3865268 (task2): 
0x3865268 (task2): 
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0x3865268 (task2): 
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0x3865268 (task2): 
0x3865268 (task2): 
0x3865268 (task2): 
0x3865268 (task2): 
0x3865268 (task2): 
0x3865268 (task2): 
0x3865268 (task2): 
0x3865268 (task2): 
0x3865268 (task2): 
0x38616e8 (task3): 
0x38616e8 (task3): 
0x38616e8 (task3): 
0x38616e8 (task3): 
0x38616e8 (task3): 
0x38616e8 (task3): 
0x38616e8 (task3): 
0x38616e8 (task3): 
0x38616e8 (task3): 
0x38616e8 (task3): 
0x38616e8 (task3): 
0x38616e8 (task3): 
0x38616e8 (task3): 
0x38616e8 (task3): 
0x38616e8 (task3): 
0x38616e8 (task3): 
0x38616e8 (task3): 
0x38616e8 (task3): 
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0x38616e8 (task3): 
0x38616e8 (task3): 
0x38616e8 (task3): 
0x38616e8 (task3): 
0x38616e8 (task3): 
0x38616e8 (task3): 
0x38616e8 (task3): 

而且sched在执行taskspawn的时候，还出现了taskspawn failed错误，既然taskspawn错误了，为何最终3个还是生成了、执行了？

[ies_sweet]

顶贴，学习中，愿高手指点迷津。