High ping with Ubuntu 17.10 host

Question

When pinging the computers in my WLAN all hosts (router, raspi, Debian Stretch desktop, ...) have low latencies of a few ms, except for one: my Ubuntu 17.10 desktop has latencies of 50 to several 100 ms; this makes working in the shell almost impossible.

This seems to be a SOFTWARE problem:

1. The problem started some weeks ago. I think it coincided with my upgrade from Ubuntu 16.04 LTS to Ubuntu 17.10. Before that, latency was no problem.

2. The same computer, no changes, has excellent latency when running Windows 10 instead of Ubuntu 17.10. With Knoppix 8.2, however, latency is bad, too.

3. Both Windows 10 and Ubuntu 17.10 use the 2.4 GHz frequency range and the router is locked to a fixed channel within that range.

4. Forcing Ubuntu 17.10 (and the router) to use other channels or the 5 GHz range has no effect.

5. With Ubuntu 17.10, when switching WLAN off and then on again, latency is excellent for roughly 5 seconds and then gets and stays bad.

I would be very grateful for any idea what the problem could be.

Answer 1

I have the same problem. I found a response here

Basically, it is caused by the power management features. After disable it, the latency improves a lot.

sudo iwconfig wlan0 power off