On Mon, Jul 13, 2015 at 10:23:02PM +0200, Johann Obermayr wrote:
> Am 13.07.2015 um 21:58 schrieb Gilles Chanteperdrix:
> >On Mon, Jul 13, 2015 at 07:26:11PM +0200, Johann Obermayr wrote:
> >>Am 13.07.2015 um 19:21 schrieb Gilles Chanteperdrix:
> >>>Johann Obermayr wrote:
> >>>>Am 13.07.2015 um 17:24 schrieb Gilles Chanteperdrix:
> >>>>>Johann Obermayr wrote:
> >>>>>>without your application, there are no large latencies.
> >>>>>>with your application see frozen.txt (with latency -f)
> >>>>>I am confused. You mean "our application", not "your application",
> >>>>>right?
> >>>>>lrtdrv_monitoring_irq is not part of the code delivered by the Xenomai
> >>>>>project.
> >>>>>
> >>>>>>We see the problem only if one task (background) is accessing the SRAM
> >>>>>>on your PCI-Card. if we stop this task, all is ok.
> >>>>>Again: the Xenomai project does not make PCI-card. So, you probably mean
> >>>>>"our PCI-Card"?
> >>>>yes, our PCI-Card. (sorry for my bad english)
> >>>>>>So we have a higher prior task (pci-locker), that interrupt the
> >>>>>>background task, so that the pci bus get free.
> >>>>>I am not sure I understand your explanations. But the trace is pretty
> >>>>>clear:
> >>>>>
> >>>>>At time -658 the timer is programmed to tick at -561.
> >>>>>
> >>>>>>:| # event tick@-561 -658 0.112 xntimer_next_local_shot+0xca
> >>>>>>:| + func -651 0.145 lrtdrv_monitoring_irq+0x4
> >>>>>>[sigmatek_lrt] (irq_hook_handler+0x32 [sigmatek_lrt])
> >>>>>>:| + end 0x000000ef -651! 641.640 apic_timer_interrupt+0x52
> >>>>>>(<102d0254>)
> >>>>>But at that point the tick is delayed for 600us. And according to the
> >>>>>trace, the last traced function called before that delay is the function
> >>>>>
> >>>>>ltdrv_monitoring_irq.
> >>>>>
> >>>>>So, I do not know what this irq is doing, but I would suggest having a
> >>>>>close look at it.
> >>>>>
> >>>>>
> >>>>hello,
> >>>>
> >>>>i have disable our lrtdrv_monitoring_irq.
> >>>>Only have this callback
> >>>>static void irq_hook_handler(unsigned int irq, unsigned int state)
> >>>>{
> >>>> if (fpga_interrupt == irq && state == 0x01)
> >>>> {
> >>>> time_fpga_irq = rt_timer_tsc();
> >>>> }
> >>>>}
> >>>>same latency
> >>>Maybe, but your trace does not contain enough points to see it. The trace
> >>>should at least contain the "tick@" event which gets missed, so that we
> >>>can see how much the interrupt is delayed, and what was happening at the
> >>>time.
> >>>
> >>>
> >>Hi,
> >>
> >>Sorry, here with more points.
> >Ok, what is irq_hook_handler ?
> >
> Ok. on out PCI Card there is a FPGA. This FPGA generate am Interrupt to the
> PC. But internal in the FPGA there
> are different IRQ sources. One of them is our Tick.
> So we measure the time from __ipipe_handle_irq to the our rtdm_irq_request
> handler.
> In our handler we can check, if it our Tick and than we can calc the correct
> time to start our pci_locker task 50us before next Tick-irq.
>
> It's a callback function from some irq function ipipe_raise_irq,
> __ipipe_do_IRQ, __ipipe_handle_irq
> for our own tracing and it save the fpga irq time.
> Only __ipipe_handle_irq have state 0x01 (begin irq) & state 0x02 at the end
> of the function.
I see two weird things in your traces:
- irq_hook_handler which is taking a lot of time
- or some APIC related functions taking a lot of time.
Are you sure your system is not one of those which disable the APIC
during idle period. Is your system UP or SMP?
--
Gilles.
https://click-hack.org
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