Well one of my 8khz tasks in kernel space seems to require T_FPU despite me never using it. I've been able to reproduce my bug within a minute several times without that flag, but if the flag is set, it can run for an hour without a single value being corrupted into NaN.
I also am getting a lot of page faults with ipipe_handle_irq() in the back trace. I'm also noticing if I have T_WARNSW on for a primary mode only thread, it will receive the signal if I create a Linux-only thread with pthread_create() and that's just weird. I don't think the problem is IO time. It's definitely context switching and things. IRQ0 handler uses up to 20% of the cpu, and that just seems wrong. It gets worse if I try the other scalability options (tree or hash.) It uses a lot of CPU time even when the tasks are delayed on conditional variables. I don't have periodic timing on, either. I never used to notice such high CPU usage with older versions of Xenomai. I even had an application written that ran all these threads and didn't have a problem with it. I'll hopefully find some time soon to write isolated tests and try to figure out what's going on. The page fault problems (there are more than the one I posted earlier) are really getting annoying, too. Sadly my contractor is on the verge of scrapping Xenomai for their project because of these problems. :( I really believe in it, but I'm basically working two jobs and don't have all the time I wish I did to help test. And Paul, it is only on x86. Steven > -----Original Message----- > From: Gilles Chanteperdrix [mailto:[EMAIL PROTECTED] > Sent: Monday, February 11, 2008 9:10 AM > To: Steven Seeger > Cc: Jan Kiszka; [email protected] > Subject: Re: [Xenomai-help] overhead > > On Mon, Feb 11, 2008 at 4:20 PM, Steven Seeger > <[EMAIL PROTECTED]> 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. > > user-space adds some overhead compared to kernel-space. Enabling the > T_FPU bis for a task which does not need also adds the useless > overhead of saving/restoring FPU upon context switch. > > -- > Gilles Chanteperdrix _______________________________________________ Xenomai-help mailing list [email protected] https://mail.gna.org/listinfo/xenomai-help
