Very slow network speed using Tinc

[Guus Sliepen]

On Tue, Oct 22, 2013 at 07:37:07PM +0200, Florent Bautista wrote:

> > If you are expecting gigabit/s speeds, then you have to try tinc 1.1 from git
> > and use it on processors which have hardware AES instructions.
> 
> Interesting, only 1.1 uses hardware AES instructions ?

Both tinc 1.0 and 1.1 can use hardware AES instructions. However, the latest
version of tinc 1.1 from the git repository uses AES in GCM mode, and if your
processor also supports the PCLMULQDQ instruction (most of the processor that
support AES also support PCLMULQDQ) then this gives an enormous speed boost.
There are also processors without AES but with PCLMULQDQ, which still get a big
boost. On processors that do not support either of these instructions, GCM mode
will still give a small speed boost over the CBC+HMAC mode of encryption and
authentication which is used in tinc 1.0.

If you compile tinc 1.1 from git, it will also create a binary called
"sptps_speed". This will test the performance of the new protocol used in tinc
1.1. The last line of output is the most relevant one, and tells you the speed
you can get, although it does not include the overhead of sending/receiving
packets to/from the network and the tun/tap device.

An example from a server with a Xeon E5420 processor (no AES, no PCLMULQDQ):

$ ./sptps_speed
[...]
SPTPS/UDP transmit for 10 seconds:         859.85 Mbit/s

From a low-power server with a i3-3220T processor (only PCLMULQDQ):

SPTPS/UDP transmit for 10 seconds:           1.66 Gbit/s

From a laptop with a i5-4200U processor (both AES and PCLMULQDQ):

SPTPS/UDP transmit for 10 seconds:           6.39 Gbit/s

> Is 1.1 multi-threaded too ?

No. The results from sptps_speed are also from a single thread.

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