GRE/gif/netgraph tunnel speed on 10Gbit channel

[Rodney W. Grimes]

> Am 29.05.2018 um 13:33 schrieb Vitalij Satanivskij:
> 
> MM> Can you try MTU 1400 on GRE0 and MSS of 1300 just for testing?
> MM> With this values I get 4600Mbit sending and 1400Mbit receiving with 
> MM> iperf and 10 parallel streams.
> MM> 
> 
> UUUPSS looks like i have problem with metodology 
> 
> I'm use iperf3 and even with -P10 or run's in parallel (on diferents ports) it show summary of +-2gbits max

Iperf3 is known not to do Parallel well:
-P, --parallel n
              number of parallel client streams to run. Note that iperf3 is
              single threaded, so if you are CPU bound, this will not yield
              higher throughput.

I suggest using iperf for -P tests that cause the single thread of
iperf3 to become CPU bound.

> 
> While iperf v2 show 4+gbit's 
> 
> [ ID] Interval       Transfer     Bandwidth
> [ 11]  0.0- 0.0 sec  0.00 Bytes  0.00 bits/sec
> [ 10]  0.0-20.0 sec   910 MBytes   382 Mbits/sec
> [  9]  0.0-20.0 sec   503 MBytes   211 Mbits/sec
> [  8]  0.0-20.0 sec  1.66 GBytes   714 Mbits/sec
> [ 12]  0.0-20.0 sec  2.25 GBytes   965 Mbits/sec
> [  7]  0.0-20.0 sec   368 MBytes   154 Mbits/sec
> [  6]  0.0-20.0 sec  1.90 GBytes   815 Mbits/sec
> [  5]  0.0-20.0 sec   900 MBytes   378 Mbits/sec
> [  4]  0.0-20.0 sec   833 MBytes   349 Mbits/sec
> [  3]  0.0-20.0 sec  1.11 GBytes   478 Mbits/sec
> [SUM]  0.0-20.0 sec  10.4 GBytes  4.44 Gbits/sec
> 
> 
> It's very strange for me but at last it mutch more beter. 
> 
> Ok now question is - which maximum speed we can get from gre on 10Gbit link's. ^) 

-- 
Rod Grimes                                                 rgrimes at freebsd.org