RTT reporting

[TobiPletsch]

When a path is fairly stable in throughput, the ACK Ratio increases. When the ACK ratio increases to high values, i get reportet RTTs of over 1s at times, although latency was set to 12ms for that path. Other paths with tc latencies such as 40ms and as CPF paths with lower priority had variable throughput and RTT reporting was accurate.
In the below example i varied Path 1 tc latency within 1ms to attempt to get throughput variations for more accurate RTT reporting
Example:

The below plot shows 3 paths with CPF scheduling at first (green has highest, orange has second highest, red has lowest). Green is visibly throughput stable, but the RTT goes through the roof. Orange RTT increases, due to to +20ms /s tc latency. At 7.5 seconds, sRTT scheduling is used. At 12.5 seconds CPF is turned on again.