[etherlab-users] skipped/unmatched datagrams - at startup - safe to ignore?
mbec at gmto.org
Wed Jun 27 21:02:52 CEST 2012
I've isolated the problem to one specific module, namely the bh_el6688
(ptp sync) module. Leaving it out my configuration, I can go full cycle
with all the other modules in one step.
On 06/26/12 14:55, Matthieu Bec wrote:
> Yes I'm using RT_PREEMPT, but the ethercat layer of my application is
> implemented as a kernel module. It starts with a preset cycle time, the
> 'workaround' lets me change it by ioctl.
> I tried different bus topologies, number of terminals, different number
> of domains, mostly same results. Oddly I often get the same numbers
> reloading the kernel module (not quite always but it strucked me as
> weirdly recurring for a diagnostic printed every second with a 10kHz
> cycle): something like 24 UNMATCHED, 16 SKIPPED, usually happens twice
> and then goes away.
> it's quite possible I have a regression in my kernel app layer
> somewhere. Will post once I find something. Thanks.
> On 6/26/12 1:31 AM, Florian Pose wrote:
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>> Am 23.06.2012 01:26, schrieb Matthieu Bec:
>>> I'm now able to get reliable clean starts (no more startup
>>> warnings) by ramping up my cycle time in increments; like 1, 2, 4,
>>> 8, 10 kHz over a short period.
>>> Is anyone using similar "warm-up" technique?
>> No. I think, you should check if your RT app is causing latencies at
>> startup. Are you using RT-PREEMPT? Did you avoid causing pagefaults by
>> locking the memory and cause an initial pagefault before cyclic
>> - --
>> Best regards,
>> Florian Pose
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Matthieu Bec GMTO Corp.
cell: +1 626 354 9367 P.O. Box 90933
phone: +1 626 204 0527 Pasadena, CA 91109-0933
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