On Sun, 26 Jan 2014, Michael Haberler wrote: > Date: Sun, 26 Jan 2014 09:59:52 +0100 > From: Michael Haberler <[email protected]> > To: EMC developers <[email protected]> > Subject: Re: [Emc-developers] reports on rt-preempt / latency-test: max jitter > going down > > could the folks observing this behaviour please run the following commands on > their systems: > > cat /sys/devices/system/clocksource/clocksource0/available_clocksource > > cat /sys/devices/system/clocksource/clocksource0/current_clocksource > > background: Answer 2 of: > http://stackoverflow.com/questions/5930621/problem-of-understanding-clock-gettime > > thanks!
cat /sys/devices/system/clocksource/clocksource0/available_clocksource tsc acpi_pm cat /sys/devices/system/clocksource/clocksource0/current_clocksource tsc I changed the clocksource to acpi_pm but the error remains One interesting thing is that the error is periodic with a ~4 second period (like an uncaught 32 bit ns count wrap) > > - Michael > > > Am 25.01.2014 um 17:03 schrieb Michael Haberler <[email protected]>: > >> >> 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 > Peter Wallace Mesa Electronics (\__/) (='.'=) This is Bunny. Copy and paste bunny into your (")_(") signature to help him gain world domination. ------------------------------------------------------------------------------ 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
