Steven Seeger wrote: > The overhead was measured by only comparing cpu usage between tasks from > the statistics collection stuff. There are some userland tasks running > at 8khz, so apparently this is a problem for Xenomai on this board. I > had no problem at all with these tasks in kernel space under rtai. > > There are no faults at all under /proc/xenomai/faults. > > The main way I can tell something is wrong is that if my three fast > tasks are running (8 khz in kernel space, 8 khz in userspace, and 50 hz > in userspace) then a lower priority task will timeout and trip a > watchdog. If I remove the IO routines from the 50hz task, then the > others can still run.
I/O does not come for free (specifically on ISA HW - if that is the case for you). But if you think that this makes a difference here, what about measuring both kernel- and userland-based I/O accesses in a loop and compare the runtime? This would also allow you to quantify the impact - regardless if there is a difference or not. Jan -- Siemens AG, Corporate Technology, CT SE 2 Corporate Competence Center Embedded Linux _______________________________________________ Xenomai-help mailing list [email protected] https://mail.gna.org/listinfo/xenomai-help
