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我正在创建一个周期线程,它在模拟输出上输出一个方形信号。我使用Xenomai API的Posix Skin和Analogy。定期线程在Xenomai实时失败
我使用示波器测试了我的代码的实时性能,并查看了方波信号(频率为1kHz)上的延迟。我应该实现100us的延迟。然而,该信号是强(> 250US延迟)由常见的中断信号的扰动,如移动鼠标,开始一个新的程序等
在我的生成文件的标志被设置为这样:
gcc -I/usr/xenomai/include -D_GNU_SOURCE -D_REENTRANT -D__XENO__ -I/usr/xenomai/include/posix
main_posix.c -Xlinker -rpath -Xlinker /usr/xenomai/lib -Wl,@/usr/xenomai/lib/posix.wrappers
-L/usr/xenomai/lib -lpthread_rt -lxenomai -lpthread -lrt -lanalogy -lrtdm -o main_posix
,这是代码:
#define PERIOD 1e6
#define FILENAME "analogy0"
#define ANALOG_SUBD 1
#define CHANNEL 0
#define SCAN_SIZE 2
#define DELAI 5
static char *filename = FILENAME;
static int idx_subd = ANALOG_SUBD;
static int idx_chan = CHANNEL;
static int valueUp = 450000;
static int valueDown = 98500;
void *TaskCode(void *arg)
{
unsigned char sgnl = 0;
unsigned long overruns_r = 0;
a4l_desc_t dsc = { .sbdata = NULL };
a4l_chinfo_t *chinfo;
int err = 0;
unsigned int scan_size = SCAN_SIZE;
err = a4l_open(&dsc, filename);
if (err < 0) {
fprintf(stderr,
"insn_write: a4l_open %s failed (err=%d)\n",
filename, err);
return NULL;
}
while(1) {
pthread_wait_np(&overruns_r);
if(sgnl)
err = a4l_sync_write(&dsc,
idx_subd, CHAN(idx_chan), 0, &valueUp, scan_size);
else
err = a4l_sync_write(&dsc,
idx_subd, CHAN(idx_chan), 0, &valueDown, scan_size);
if (err < 0) {
fprintf(stderr,
"insn_write: a4l_sync_write failed (err=%d)\n", err);
goto out_insn_write;
}
sgnl = (sgnl + 1) % 2;
}
out_insn_write:
if (dsc.sbdata != NULL)
free(dsc.sbdata);
a4l_close(&dsc);
return NULL;
}
int main(void)
{
mlockall(MCL_CURRENT | MCL_FUTURE);
pthread_t thread;
int rc, i;
int prio = 99;
struct timespec rqtp, rmtp;
rqtp.tv_sec = 0;
rqtp.tv_nsec = PERIOD;
struct sched_param sparam;
sparam.sched_priority = 99;
rc = pthread_create(&thread, NULL, TaskCode, NULL);
assert(0 == rc);
rc = pthread_setschedparam(&thread, SCHED_FIFO, &sparam);
assert(0 == rc);
rc = clock_gettime(CLOCK_REALTIME, &rmtp);
assert(0 == rc);
rmtp.tv_sec = rmtp.tv_sec + DELAI;
rc = pthread_make_periodic_np(thread, &rmtp, &rqtp);
if(rc == ETIMEDOUT) printf("Début dépassé \n");
else if(rc == ESRCH) printf("Thread invalide \n");
assert(0 == rc);
rc = pthread_join(thread, NULL);
exit(EXIT_SUCCESS);
}
我强烈怀疑(通过看Xenomai调度),我的计划不知何故进入第二模式。我尝试删除“assert”语句以及相关的printf,但这并不成功。任何想法如何解决它?
您是否能够成功完成此项工作?我有一个类似的程序,它始终以次要模式执行。我尝试删除所有的'pthreads',然后运行一个'while'循环,我可以看到它在Linux中显示为一个进程。 – am3