[Freemint-list] Slow network speed

[Markus Fröschle]

Am 02.10.2016 um 15:35 schrieb Vincent Rivière:
> On 02/10/2016 at 09:02, Markus Fröschle wrote:
>> iperf can not only measure the throughput to remote machines, but also
>> (using localhost) to the local machine. If you test this, you'll
>> basically see the performance of the MiNT network stack
> Very smart, I didn't think to that.

The results are rather astonishing, actually (at least to me):

m5484lite:~#iperf -c localhost;iperf -c bums
------------------------------------------------------------
Client connecting to localhost, TCP port 5001
TCP window size: 62.7 KByte (default)
------------------------------------------------------------
[  6] local 127.0.0.1 port 1091 connected with 127.0.0.1 port 5001
[ ID] Interval       Transfer     Bandwidth
[  6]  0.0-10.1 sec  42.2 MBytes  35.2 Mbits/sec
------------------------------------------------------------
Client connecting to bums, TCP port 5001
TCP window size: 62.7 KByte (default)
------------------------------------------------------------
[  6] local 192.168.1.102 port 1094 connected with 192.168.1.61 port 5001
[ ID] Interval       Transfer     Bandwidth
[  6]  0.0-10.0 sec  86.8 MBytes  72.6 Mbits/sec

The first one just uses the loopback interface (so this is actually more 
a test of the memory bandwidth and efficiency of the network stack) 
while the second one really goes over the wire. If you'd asked me 
before, I would have expected results to be the other way round.

Just for comparision, the values of a current PC:

mfro at bums:~$ iperf -c localhost
------------------------------------------------------------
Client connecting to localhost, TCP port 5001
TCP window size: 2.50 MByte (default)
------------------------------------------------------------
[  3] local 127.0.0.1 port 45480 connected with 127.0.0.1 port 5001
[ ID] Interval       Transfer     Bandwidth
[  3]  0.0-10.0 sec  84.6 GBytes  72.6 Gbits/sec

No, this isn't faked. Its exactly 2000 times faster ;)