Hi,
As I'm trying to implement a real-time application in DROPS, I still have some questions on this topic. Maybe there's someone who can answer them because I didn't find it described it the documentation...
1. The timer granularity seems to be set to 976 microsec. Is there a special background for using this number or can I set it down (maybe even to 10 microsec, which what be a good time resolution for my task)? How can I set it? Or would it be stupid to set it to such a tiny value?
2. When looking at the rt_sched example in the hello-package: the main-thread has a preempter-thread for recognizing timeslice overrun and deadline misses. When does this preempter-thread recognize a TS overrun or a deadline miss? Right after this event (so within the next time resolution) or after the main-thread says that is has finished it's work (meaning after a call to "l4_rt_next_reservation")?
3. How can the preempter-thread tell the main-thread to stop it's work in case of a timeslice overrun or even a deadline miss?
4. Does the system allow a thread's scheduling like this: period-length = 976 microsec, timeslice_mand = 9760 microsec, timeslice_opt = 9760 microsec (which would mean that the system had to reserve timeslices that don't fit into one period...)
OR
period-length = 9760 microsec, timeslice_mand = 4380 microsec, timeslice_opt = 4380 microsec (which would mean that the system had to reserve all resources for this thread..) (what would happen if another thread comes with a period_length of also 9760 microsec and a timeslice_mand = 6000 microsec? What would be the system's behaviour?)
===================================================================== Other thing: File system support:
1. which filesystems are supported (reiserfs?)?
2. Is there a way to have RT access to disk and accessing files this way? If so, how?
Thanks, Rene