Nadym Salem wrote: > On Thu, August 16, 2007 10:38, Jan Kiszka wrote: > >>>>> I'm using two machines here, one acts as a master, other one acts as >>>>> a slave. The slave isn't able to synchronize with master when >>>>> configuring a cycle length around 10 down to 2 ms (and most probably >>>>> any cycle length lower then that). When choosing 1 second cycle >>>>> length, it syncs fine. >>>>> Capturing the whole story with wireshark shows, that slave in short >>>>> cycle configurations requests reply calibration frame e.g. in cycle >>>>> 1500, although it sends request calibration frame in cycle 1700, so >>>>> of course this can't work. As it works in 1 s cycle configuration, >>>>> only reason for this behavoir I can imagine is, that slave isn't able >>>>> to calculate and send request calibration frame early enough. But >>>>> this isn't really possible, because we're talking about a >2GHz >>>>> machine (x86). >>>> ...which is know to be free of hardware-related latency quirks (tested >>>> with Xenomai tools)? If yes, please send be your trace. >>> Don't wonder I'm answering :-) >>> attached a complete log of xeno-test, do you also need a wireshark log ? >> Yeah, I was actually referring to the pcap file. > > attached, I cut the important lines +- some. It's the only request coming > from slave.
The master drops this request because the target slot is in the past.
What is the slot offset of the slave? ~1700 us? Could you post the full
TDMA configuration? You don't use RTcfg, correct?
-200 cycles, i.e. 4 seconds... Hmm... This sounds as weird as your
other, yet unexplained observation.
>
>> Anyway, the xeno-test looks a fishy as well. The latency tool appears to
>> run fine (except for the testing device conflicts, but that's a
>> different story), but the cyclictest is totally screwed! And these are
>> dimensions normally related to SMI etc. artefacts.
>
> Due to some error here, the SMI workaraound was not included, attached a
> new file with SMI workaroung.....but it didn't really change anything.
>
>> Please make sure no other RT load is present during the test (just in
>> case) and re-run latency and cyclictest stand-alone for several minutes
>> each. If strange numbers remain (millisecond latencies...), check
>> TROUBLESHOOTING hints and then report to xenomai-help.
>
> The machine just came up and we started the test, nothing else is running.
>
> But where do you see milliseconds of latency ? I see worst values of
> around 20 microseconds.
Here:
T: 0 ( 5727) P:10 I: 1000 C: 9 Min: 19 Act: 19 Avg:
2722 Max: 6489
^^^^
Might be a problem only of the cyclictest (still worth reporting then),
but it may point at more serious issues as well.
Jan
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