Steven Seeger wrote: > 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.
Send those backtraces, please, and a disassembly of your running kernel privately to me. 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. > Sorry, I just don't understand where the problem is, or maybe I did not understand what you are exactly doing/expecting here. > 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. > If you actually take faults on behalf of the tick timer handler, then no wonder why the CPU figures explode. > I never used to notice such high CPU usage with older versions of > Xenomai. Older versions, or older kernels? 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 > -- Philippe. _______________________________________________ Xenomai-help mailing list [email protected] https://mail.gna.org/listinfo/xenomai-help
