I sarted using yesterday a spare hAP AC2 as a "router on a stick" and I'm encountering some issues when running iperf3.
The device (RBD52G-5HacD2HnD) is running under routerOS 6.49.6 (stable) and takes care of the routing (inter-VLAN) between 2 switches, an accesspoint and the WAN port.
I'm running the following test:
- AC2 takes care of the routing / firewall rules
- iperf3 server is on VLAN-AAA
- iperf3 client is on VLAN-BBB
- iperf3 server is run on a device connected to switch1 which in turn is connected (via trunk port) to ether3 of the AC2
- iperf3 client is run on a device connected to switch2 which in turn is connected (via trunk port) to ether2 of the AC2
- iperf3 commands that are run on the client: "iperf3 -c <server_ip> -P 30 -p 5201 -bg -t 30 -4" and "iperf3 -c <server_ip> -P 30 -p 5201 -bg -t 30 -4 -R"
When running these tests, I observe three things:
- the load on the AC2 is not shared among the 4 cores (1 core is at 100%, 2 cores are at 0%, the last core is somewhere between 2% and 15%).
- CPU0 and CPU2 are rarely above 2% usage (i.e. CPU1 or CPU3 go to 100%), they are almost unused...
- the maximum throughput I get (inter-VLAN) is ~370 Mbps (while all links are 1Gbps full duplex, cables are tested)
I guess that the fact that the cores are not used evenly may cause this bottleneck/performance issue. Can anybody confirm that this may cause this issue ? (or should I look elsewhere)
Thank you for your help!
Note 1: there is no hardware offloading on the AC2
Note 2: wireless is disabled on the device
Note 3: there are ~10 VLANs
Note 4: rules-wise there are: 4 NAT rules, 3 RAW rules, 0 Mangle, fasttrack is activated, the "allow iPerf traffic" rule is the 9th rule in the forward chain (total of 159 rules including input, output and forwards for all VLANs)
Note 5: on the switches the CPU load is max 4% when running the tests
Note 6: when staying on the same switch, with the same test command, the throughput is ~960Mbps
Note 7: The "CPU usage issue" is very similar to this one, but with ahAP AC2 instead of a RB450Gx4: viewtopic.php?hilit=CPU&p=924912&sid=3d ... ce850ddd7f however the latest stable routerOS v6 does not fixes it for the AC2