I’ll start looking. Thanks for the pointer On 14 Jan 2014, at 19:57, Michael Haberler <mai...@mah.priv.at> wrote:
> > Am 14.01.2014 um 19:33 schrieb Charles Steinkuehler > <char...@steinkuehler.net>: > >> On 1/14/2014 12:21 PM, Bas de Bruijn wrote: >>> Yes, the BeagleBone Black, >>> the PRU is hat 10us step length and 1us step time. > > The PRU code cannot cause an "unexpected realtime delay", since this is a > message generated by the motion component. Since missing steps have no way to > find their way back into HAL except if you are running a stepper servo loop > with encoders (which you likely dont), this cannot be the source either. > > The logic for "unexpected realtime delay" is here: > https://github.com/mhaberler/linuxcnc/blob/unified-build-candidate-3/src/emc/motion/control.c#L249 > > > What motion does is: > - observes its invocation interval over a window of samples, > - once the window is filled with samples, start checking: > - compare the current invocation time to all samples > - if the current interval is longer than 1.2 of any of the samples then > generate an "unexpected realtime delay" message. > > What you want to do is investigate the functions on the servo thread. > > see the 'show thread' and 'show param' commands > http://www.linuxcnc.org/docs/devel/html/hal/tutorial.html, in particular the > '.time' and '.tmax' values, which might give a hint which thread function > takes too long. > > It might be worth looking at motion execution times, see the PARAMETERS > section ofhttp://www.linuxcnc.org/docs/devel/html/man/man9/motion.9.html. > > - Michael > >>> The servo task period, in nano sec is 1000000. >>> When i run a latency test i get a jitter of approximately 56000 to 60000 ns >>> max Jitter >>> >>> I’ll disable the screensaver to check. >> >> The latency you report is typical for the BeagleBone. The "unexpected >> realtime delay" is something I see occasionally on my systems. I >> haven't fully dug into the cause, but it seems like something in >> LinuxCNC has hard-coded jitter numbers and doesn't like the BeagleBone >> (which has higher IRQ jitter than a typical x86 system). I've never had >> it cause issues, however, and it is not correlated with a spike in >> latency as measured by either the LinuxCNC latency-test or the xenomai >> latency utility. >> >> I also run with the screen saver and display power management enabled on >> my BeagleBone and have not had any issues with "missed steps". >> >> I suggest you review the current setting on your stepper drivers, >> cooling on the stepper drivers, the mechanical system (make sure >> everything moves freely and can't bind), and review your machine setup. >> >> I did have to dial my acceleration down to around 2400 mm/s/s to avoid >> missing steps with some Slic3r generated infill gcode, but that had >> nothing to do with the BeagleBone, my steppers and drivers just weren't >> up to the task when running off 12V. >> >> -- >> Charles Steinkuehler >> char...@steinkuehler.net >> >> ------------------------------------------------------------------------------ >> CenturyLink Cloud: The Leader in Enterprise Cloud Services. >> Learn Why More Businesses Are Choosing CenturyLink Cloud For >> Critical Workloads, Development Environments & Everything In Between. >> Get a Quote or Start a Free Trial Today. >> http://pubads.g.doubleclick.net/gampad/clk?id=119420431&iu=/4140/ostg.clktrk_______________________________________________ >> Emc-users mailing list >> Emc-users@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/emc-users > > > ------------------------------------------------------------------------------ > CenturyLink Cloud: The Leader in Enterprise Cloud Services. > Learn Why More Businesses Are Choosing CenturyLink Cloud For > Critical Workloads, Development Environments & Everything In Between. > Get a Quote or Start a Free Trial Today. > http://pubads.g.doubleclick.net/gampad/clk?id=119420431&iu=/4140/ostg.clktrk > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------------------------------------------------------ CenturyLink Cloud: The Leader in Enterprise Cloud Services. Learn Why More Businesses Are Choosing CenturyLink Cloud For Critical Workloads, Development Environments & Everything In Between. Get a Quote or Start a Free Trial Today. http://pubads.g.doubleclick.net/gampad/clk?id=119420431&iu=/4140/ostg.clktrk _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
