Re: [Xenomai-help] How can I now when it will be next periodic task release point?

[Jan Kiszka <jan.kiszka@domain.hid>]

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Rodrigo Rosenfeld Rosas wrote:
> I want to capture and process images each 300 ms. The processing routines take 
> a (fixed, but unknown) time. I'd like to request a new image about 50 ms 
> before next release point, like this:
> 
> for(;;)
> {
> 	rt_task_wait_period(NULL);
> 	ProcessImage();
> 	rt_task_sleep(XXX); // until 50 ms before next release point
> 	RequestNewImage();
> }
> 
> I could use rt_task_inquire() if RT_TASK_INFO was documented. From 
> source-code:
>   RTIME relpoint;             /* !< Periodic release point. */
> 
> The question is which release point? Next or the last reached?

Looks like you managed to dig out dead/broken code here: RT_TASK.timer,
the timer returned in relpoint, is nowhere else used than in
rt_task_inquire.

> Anyway, a new function like rt_task_getnextrelpoint() would be very welcome...
> 
> rt_task_sleep(rt_task_getnextrelpoint() - 50*1000*1000);

See my attached patch. It should fix rt_task_inquire in a way that meets
your requirements. It also clarifies the doc. Only compile tested.

Philippe, is it correct?

Jan

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Index: include/native/task.h
===================================================================
--- include/native/task.h	(Revision 1374)
+++ include/native/task.h	(Arbeitskopie)
@@ -76,7 +76,7 @@ typedef struct rt_task_info {
 
     unsigned status;		/* !< Status. */
 
-    RTIME relpoint;		/* !< Periodic release point. */
+    RTIME relpoint;		/* !< Next periodic release point. */
 
     char name[XNOBJECT_NAME_LEN]; /* !< Symbolic name. */
 
@@ -109,8 +109,6 @@ typedef struct rt_task {
 #define link2rtask(laddr) \
 ((RT_TASK *)(((char *)laddr) - (int)(&((RT_TASK *)0)->link)))
 
-    xntimer_t timer;
-
     xnthread_t thread_base;
 
     char rname[XNOBJECT_NAME_LEN]; /* !< Name in registry. Not the same as
Index: ChangeLog
===================================================================
--- ChangeLog	(Revision 1374)
+++ ChangeLog	(Arbeitskopie)
@@ -1,3 +1,8 @@
+2006-07-25  Jan Kiszka  <jan.kiszka@domain.hid>
+
+	* include/native/task.h, ksrc/native/task.c: Kill unused timer field
+	in RT_TASK. Return ptimer of the underlying thread on rt_task_inquire.
+
 2006-07-23  Jan Kiszka  <jan.kiszka@domain.hid>
 
 	* ksrc/skins/native/Makefile: Fixed typo that messed up modularised
Index: ksrc/skins/native/task.c
===================================================================
--- ksrc/skins/native/task.c	(Revision 1374)
+++ ksrc/skins/native/task.c	(Arbeitskopie)
@@ -1118,7 +1118,7 @@ int rt_task_inquire(RT_TASK *task, RT_TA
 	info->bprio = xnthread_base_priority(&task->thread_base);
 	info->cprio = xnthread_current_priority(&task->thread_base);
 	info->status = xnthread_status_flags(&task->thread_base);
-	info->relpoint = xntimer_get_date(&task->timer);
+	info->relpoint = xntimer_get_date(&task->thread_base.ptimer);
 
       unlock_and_exit:
 

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