Hi
I want to solve a problem on my router (tp-link c7) whish has weak performace only 20mbit/s from 100mbit/s posible.
when i start top i see openvpn uses 96% cpu, general load is about 1.0, but general CPU usage is less then 50%
,
must i only upgrade CPU (by changing router to wrt 1900acs) to have better performace or is there an other bottleneck?
CPU consumption is not 50%, it's exactly 96% and fully consumed by Openvpn. If you sum: 47% usr + 25% system + 24% softirq you get exactly 96%, so CPU is currently the bottleneck here.
OpenVpn de/encryption tasks are -very- CPU expensive.
..and/or (depending on how you look at it) the SoC is slow 
20mbit is pretty much what you'll get on MIPS.
Either switch to another less cpu intensive vpn solution or get a beefier router.
Curious, are you running SQM or not, or anything else than OpenVPN? I had heard that OpenVPN uses some resources, but wow...
All my C7 experience is just running cake for SQM... nothing else on the house firewall/AP router. Had been wondering how much else other things might use up, CPU wise.
Trank for Reply
I think i will use Other Router with stronger soc
I can Not change Software because The VPN Server is Used By other People and i do Not Want to change to much on a Running System
No i dont use sqm Or so. I dont now in this will help in this case, because The VPN use UDP Connection ...
Sounds like the way to go, if VPN is using up that much. I asked since I was wondering if that 95% CPU use was just OpenVPN, or also with SQM...
A C7 doing nothing else should be good for >350mbit, over the ethernet, or >240 over 5Ghz wifi.. (at least with my AC1200 USB adapter on the other end) But if you turn on SQM, it will work not quite that fast, but be CPU saturated at 100-120mbits.
SQM would load you even more, but provide low latency, great load sharing, bufferbloat prevention, and on 2.4Ghz, wifi airtime fairness.. which will be nice, but not make life easier on the router. On the wrt1900acs, you probably could do both VPN and SQM without getting overloaded. Try it and let us know when you get the chance!
Ok Now i have changed my Router to Linksys 3200ACM and i can give you my feedback to my CPU-Problem.
With this Router my OpenVPN connection is very fast.On my Test i can reach about 50mbit/s - 100mbit/s.
So my Problem is solved.