Here are parts of route cache from three different servers that are NOT under high load.
# ip route show cache | grep -B 1 rtt
local 127.0.0.1 from 127.0.0.1 dev lo
cache <local> mtu 16436 rtt 106ms rttvar 155ms cwnd 7 advmss 16396 hoplimit 64
...
local 127.0.0.1 from 127.0.0.1 dev lo
cache <local> mtu 16436 rtt 145ms rttvar 130ms cwnd 6 advmss 16396 hoplimit 64
...
local 127.0.0.1 from 127.0.0.1 dev lo
cache <local> mtu 16436 rtt 172ms rttvar 205ms cwnd 5 advmss 16396 hoplimit 64
Why may be rtt so high and so noisy (rttvar is quite high too) ? How can I interpret these values?