Peter Wallace kindly help to locate the error, it is rtapi_get_time() going backwards occasionally on rt-preempt, suggesting the cause is this function:
https://github.com/mhaberler/linuxcnc/blob/e3de5bb74857bbd9935c1a1d1f031a0558ca0f85/src/rtapi/rtapi_time.c#L166 this cause the 'del' variable in https://github.com/mhaberler/linuxcnc/blob/e3de5bb74857bbd9935c1a1d1f031a0558ca0f85/src/hal/components/timedelta.comp to become negative at times, causing the decreasing jitter no fix yet, but we know where to look -m Am 25.01.2014 um 08:43 schrieb Michael Haberler <[email protected]>: > Reading back on IRC I found hints at rt-preempt ubc3 builds showing the max > latency going down occasionally. > > Please: > > 1. report the exact kernel version, in particular if this is stock debian > rt-preempt kernel. > 2. check if ntp is running or not, i.e. the output of 'ps ax|grep ntp' > 3. If yes, please stop the ntp demon with 'sudo /etc/init.d/ntp stop' or > equivalent > 4. Re-run latency-test after ntp is stopped. Does the problem reoccur? > 5. Please report your results using the ubc issue tracker as mentioned here > http://static.mah.priv.at/public/html/common/UnifiedBuild.html#_issue_tracker > , for this issue: https://github.com/zultron/linuxcnc/issues/72 > > background: there is a chance that the issue is related to the behavior > described here, in particular the subtle difference between CLOCK_MONOTONIC > and CLOCK_MONOTONIC_RAW: > > > http://stackoverflow.com/questions/3657289/linux-clock-gettimeclock-monotonic-strange-non-monotonic-behavior > http://markmail.org/thread/54bb663vi47kjxnu > > - Michael > > > > ------------------------------------------------------------------------------ > 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-developers mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-developers ------------------------------------------------------------------------------ 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-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-developers
