High NIC usage (maybe WDS related?)

Hi,

I've got a WDS setup with two routers running OpenWrt 18.06. One router is Linksys WRT1900ACS v1, the other is v2.

When I ssh into each router and run "top" I notice that NIC is permanently hovering between 90% to 100% but there isn't much/any real traffic going on between wireless peers. Is this normal or is my WDS setup screwed up?

I've got STP enabled on the LAN interface for both routers.

Thanks,
Gili

I think that you may have done two mistakes:

  • nic does not mean the network, but "nice"
  • BusyBox top output can be a bit unclear, so are you sure that it is not 90% "idle" instead. Columns can be mixed easily

I think you're right. I'm seeing:

CPU: 3% usr 3% sys 0% nic 92% idle 0% io 0% irq 0% sirq

I assumed "CPU" was a field but looking again I guess it is not. So you're saying the router is 92% idle? Okay, so a follow-up question: why do I sometimes see a very high load average (e.g. 5.2) but nothing is going on in "top"?

Or put another way: if the load average is high, how do I track it down to the source?

Thanks,
Gili

just run top again and watch the %CPU column and see what command/process is responsible for the load.

1 Like

Look at the 'io' percent: That's the number of i/o wait states and even only a few percent can really bump the load for applications that are i/op bound.