Tinc performance on a Dir-300

[Guus Sliepen]

On Mon, Sep 20, 2010 at 04:37:03PM +0200, Clemens John wrote:

> we are using Tinc in our Freifunk Network in Oldenburg for internode 
> connections over the internet. So Tinc is running on OpenWrt 10.03 on Dlink 
> Dir-300 Routers.
> We all have enough internet bandwith (1,6 MB/sec and more) but we only get a 
> maximum speed of ~350KB/sec between two tinc nodes because then tinc uses 99% 
> of the cpu.
> 
> Is it possible to get more Speed with tinc on this machines? I think we have 
> compression and encryption already turned off so what is using the cpu?
[...]
> If there is no way to get more speed, do you know another VPN-Solution which 
> is better concerning speed? We dont need security because the network is 
> completely open, but we need speed.

Are you sure you have 1.6 MB/sec both upstream and downstream?

You can try other VPN software, such as OpenVPN or perhaps VDE, and see if
those are faster.  Maybe you can also try profiling tinc (either with
valgrind's callgrind tool, or compile tinc with -pg in both CFLAGS and LDFLAGS
so you can use gprof) to see where the bottleneck is.

However, the Dir-300 has a MIPS processor running at 182 MHz with only 16 kB
instruction and 16 kB data cache. That means it is not very fast, especially
not if a packet has to go all the way to userspace to be processed by tinc and
back.

-- 
Met vriendelijke groet / with kind regards,
     Guus Sliepen <guus at tinc-vpn.org>
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