Hi all, I'm trying RTNet (an old version: 0.9.13) on Xenomai (yet another old version, 2.5.6: unluckily I cannot move to newer versions).
My setup has 3 identical nodes on isolated RT network: cycle time of 5000us, master with slot offset 0, slave A with slot offset 200us and slave B with slot offset 400us; network is configured using rtnet utility script. Using rtping I observe two different behaviors on slaves and master. For example, pinging slave A from B: ... 64 bytes from 10.0.43.91: icmp_seq=1 time=7777.7 us 64 bytes from 10.0.43.91: icmp_seq=2 time=7846.3 us 64 bytes from 10.0.43.91: icmp_seq=3 time=7966.6 us 64 bytes from 10.0.43.91: icmp_seq=4 time=8096.6 us ... 64 bytes from 10.0.43.91: icmp_seq=15 time=9461.7 us 64 bytes from 10.0.43.91: icmp_seq=16 time=9604.2 us 64 bytes from 10.0.43.91: icmp_seq=17 time=4719.5 us 64 bytes from 10.0.43.91: icmp_seq=18 time=4844.7 us 64 bytes from 10.0.43.91: icmp_seq=19 time=4968.3 us 64 bytes from 10.0.43.91: icmp_seq=20 time=5124.4 us ... 64 bytes from 10.0.43.91: icmp_seq=53 time=9215.4 us 64 bytes from 10.0.43.91: icmp_seq=54 time=9331.5 us 64 bytes from 10.0.43.91: icmp_seq=55 time=9461.0 us 64 bytes from 10.0.43.91: icmp_seq=56 time=9585.3 us 64 bytes from 10.0.43.91: icmp_seq=57 time=4712.5 us 64 bytes from 10.0.43.91: icmp_seq=58 time=4847.0 us 64 bytes from 10.0.43.91: icmp_seq=59 time=4967.2 us ... so time varies between a minimum equal to time distance between two slots and a maximum equal to this time plus cycle duration. This can makes sense supposing that Linux timer used to generate ping request in rtping.c slowly drifts from real-time timer that governs tx slot, so the duration changes between requests depending on when request happens into the TDMA cycle. Same behavior if I ping A from B or if I ping master from A or B. On master I instead observe this (pinging slave A or B equally): ... 64 bytes from 10.0.43.89: icmp_seq=1 time=2434.1 us 64 bytes from 10.0.43.89: icmp_seq=2 time=2443.1 us 64 bytes from 10.0.43.89: icmp_seq=3 time=2438.7 us 64 bytes from 10.0.43.89: icmp_seq=4 time=2450.0 us 64 bytes from 10.0.43.89: icmp_seq=5 time=2447.9 us 64 bytes from 10.0.43.89: icmp_seq=6 time=2450.6 us 64 bytes from 10.0.43.89: icmp_seq=7 time=2428.5 us 64 bytes from 10.0.43.89: icmp_seq=8 time=2442.8 us 64 bytes from 10.0.43.89: icmp_seq=9 time=2442.3 us ... ping duration is constant into a rtping execution (changes between different executions). So I'm puzzling about this difference and I wonder if this is normal or if there could be problems. Thanks in advance, regards Mauro
