RouterOS is capable of showing the status of your hardware device and it's available resources. This includes CPU load.
Above zero CPU usage usually means that your machine is doing something and that it is not in standby state. This in no way indicates a problem.
A higher than average CPU usage that stays for a long time usually indicates much traffic which is being processed by RouterOS, this includes Queues, Mangle, Firewall etc. Dynamic routing protocols also can take CPU resources in heavy traffic conditions. Still, this does not mean that your router is having trouble handling it. The number 100 does not indicate any kind of limit in your hardware power.
[email@example.com] > system resource monitor cpu-used: 41 free-memory: 31488
If your router does stay on cpu usage 100 for a lot of time, you should try the following:
- See what kind of traffic is going through your router. You can use Torch for this. An attack to the router can also cause heavy CPU load.
- Disable the interfaces and see if the problem goes away, you can also unplug the Ethernet cables to be sure the traffic is not causing it.
- Disable some or all of your Queues/Filter Rules to see if you have too many of them. You can optimize your ruleset, or use PCQ to drastically reduce the number of Queues.
- See if the cpu load numbers actually affect anything apart from the number displayed. The fact that the router is doing something does not imply any kind of problem, you should only investigate if there are visible problems with the operation of the router.
- Spanish version: Uso del CPU