Re: [Xenomai] usage of rtdm_task_sleep_abs

["Gilles Chanteperdrix" <gilles.chanteperdrix@xenomai.org>]

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.


-- 
                                            Gilles.
https://click-hack.org