On Fri, Apr 18, 2008 at 4:33 PM, Bosko Radivojevic <[EMAIL PROTECTED]> wrote: > Hi, > > I'm having (from my perspective) too big jitter on handling > interrupts. System is: ARM9, AT91SAM9260, Kernel 2.6.20.21, Adeos > 1.8-03, Xenomai-2.4.2, interrupt is generated every 1ms, externally.
It's funny to notice how much you asked for the 2.6.24 patch for actually not using it. > Interrupt source (ET1200) is connected to IRQ1 pin (PC15). I'm using > native skin from user space. Usually, handler 'reacts' after ~110us, > but, worst case delay is around 250us! Is this performance > normal/expected on my platform? Why the difference is so huge? > > Is there anything I can do to get better results (with this hw:)? 250 us is the user-space dispatch latency you obtain with the "latency" test on a properly loaded target. It is the time for a user-space context switch with a full cache flush. To reduce this latency you have to: - handle interrupts in kernel space, so that you will be limited by interrupt latency, not user-space scheduling latency - use trunk so that user-space context switches involving real-time threads do not happen with hardware interrupts off. -- Gilles _______________________________________________ Xenomai-help mailing list [email protected] https://mail.gna.org/listinfo/xenomai-help
