Improving packets/sec and data rate - v1.0.24

[Jared Ledvina]

Hi,

We've been running tinc for a while now but, have started hitting a
bottleneck where the number of packets/sec able to be processed by our
Tinc nodes is maxing out around 4,000 packets/sec.

Right now, we are using the default cipher and digest settings (so,
blowfish and sha1). I've been testing using aes-256-cbc for the cipher
and seeing ~5% increases across the board. Each Tinc node does have
AES-NI. 

I've also read through/found https://github.com/gsliepen/tinc/issues/110
which is very interesting. 

The TInc nodes are all on Centos6 AWS EC2 instances as c3.large's w/
EIP's. I've been testing with iperf3 and am able to get around 510Mb/s
on the raw network. Over the tun interface/Tinc network, I'm only able
to max it out to around 120Mb/s. 

Anyone have any suggestions on settings or system changes that might be
able to assist here? I'm also curious if upgrading to 1.0.31 would help
and plan on testing that tomorrow. 

Happy to provide any other information that might be useful. 

Thanks,
Jared