I have two raspberries, RPIB with raspbian as an OS (pi user), and RPI2 wih osmc as an OS (osmc user).
I have made two tests.
The first test is iperf server on RPI2 and client on RPIB.
osmc@osmc:~$ iperf -s
------------------------------------------------------------
Server listening on TCP port 5001
TCP window size: 85.3 KByte (default)
------------------------------------------------------------
[ 4] local 192.168.5.50 port 5001 connected with 192.168.5.60 port 58922
[ ID] Interval Transfer Bandwidth
[ 4] 0.0-10.0 sec 53.9 MBytes 45.0 Mbits/sec
pi@raspberrypi:~ $ iperf -c 192.168.5.50
------------------------------------------------------------
Client connecting to 192.168.5.50, TCP port 5001
TCP window size: 43.8 KByte (default)
------------------------------------------------------------
[ 3] local 192.168.5.60 port 58922 connected with 192.168.5.50 port 5001
[ ID] Interval Transfer Bandwidth
[ 3] 0.0-10.0 sec 53.9 MBytes 45.0 Mbits/sec
If I swithc the sides I get different results:
pi@raspberrypi:~ $ iperf -s
------------------------------------------------------------
Server listening on TCP port 5001
TCP window size: 85.3 KByte (default)
------------------------------------------------------------
[ 4] local 192.168.5.60 port 5001 connected with 192.168.5.50 port 49726
[ ID] Interval Transfer Bandwidth
[ 4] 0.0-10.0 sec 97.8 MBytes 81.6 Mbits/sec
osmc@osmc:~$ iperf -c 192.168.5.60
------------------------------------------------------------
Client connecting to 192.168.5.60, TCP port 5001
TCP window size: 43.8 KByte (default)
------------------------------------------------------------
[ 3] local 192.168.5.50 port 49726 connected with 192.168.5.60 port 5001
[ ID] Interval Transfer Bandwidth
[ 3] 0.0-10.0 sec 97.8 MBytes 81.9 Mbits/sec
I have executed tests several times and result is always the same.
Can someone explain the difference in the speed?
Original Raspberry Pi 1 ?
Kodi is running on OSMC during the test ?
If so, that is why. The mere act of having Kodi running on a Pi 1 consumes enough CPU time to drop Ethernet throughput to about half of the maximum possible. The Pi 1 just has a really slow CPU.
Try stopping Kodi then re-run your test:
sudo systemctl stop mediacenter
Also if you are really trying to directly compare the performance of the two Pi’s you should not be testing between them but to a 3rd much faster machine such as a PC. Otherwise you are testing the sending performance of one Pi at the same time as the receiving performance of the other and vica versa - you will not be able to get meaningful results by doing that as you will not know which Pi is causing the issue.
1 Like
After stopping kodi on osmc (192.168.5.50) the results are still disbalanced.
raspbian server
root@raspberrypi:/home/pi# iperf -s
------------------------------------------------------------
Server listening on TCP port 5001
TCP window size: 85.3 KByte (default)
------------------------------------------------------------
[ 4] local 192.168.5.60 port 5001 connected with 192.168.5.50 port 45372
[ ID] Interval Transfer Bandwidth
[ 4] 0.0-10.1 sec 89.0 MBytes 74.1 Mbits/sec
[ 5] local 192.168.5.60 port 5001 connected with 192.168.5.50 port 45374
[ 5] 0.0-10.0 sec 97.6 MBytes 81.5 Mbits/sec
[ 4] local 192.168.5.60 port 5001 connected with 192.168.5.50 port 45376
[ 4] 0.0-10.0 sec 95.8 MBytes 80.0 Mbits/sec
osmc client
root@osmc:/home/osmc# iperf -c 192.168.5.60
------------------------------------------------------------
Client connecting to 192.168.5.60, TCP port 5001
TCP window size: 43.8 KByte (default)
------------------------------------------------------------
[ 3] local 192.168.5.50 port 45372 connected with 192.168.5.60 port 5001
[ ID] Interval Transfer Bandwidth
[ 3] 0.0-10.0 sec 89.0 MBytes 74.5 Mbits/sec
root@osmc:/home/osmc# iperf -c 192.168.5.60
------------------------------------------------------------
Client connecting to 192.168.5.60, TCP port 5001
TCP window size: 43.8 KByte (default)
------------------------------------------------------------
[ 3] local 192.168.5.50 port 45374 connected with 192.168.5.60 port 5001
[ ID] Interval Transfer Bandwidth
[ 3] 0.0-10.0 sec 97.6 MBytes 81.9 Mbits/sec
root@osmc:/home/osmc# iperf -c 192.168.5.60
------------------------------------------------------------
Client connecting to 192.168.5.60, TCP port 5001
TCP window size: 43.8 KByte (default)
------------------------------------------------------------
[ 3] local 192.168.5.50 port 45376 connected with 192.168.5.60 port 5001
[ ID] Interval Transfer Bandwidth
[ 3] 0.0-10.0 sec 95.8 MBytes 80.2 Mbits/sec
root@osmc:/home/osmc#
osmc server
root@osmc:/home/osmc# iperf -s
------------------------------------------------------------
Server listening on TCP port 5001
TCP window size: 85.3 KByte (default)
------------------------------------------------------------
[ 4] local 192.168.5.50 port 5001 connected with 192.168.5.60 port 59546
[ ID] Interval Transfer Bandwidth
[ 4] 0.0-10.0 sec 53.6 MBytes 44.8 Mbits/sec
[ 5] local 192.168.5.50 port 5001 connected with 192.168.5.60 port 59547
[ 5] 0.0-10.0 sec 53.4 MBytes 44.6 Mbits/sec
[ 4] local 192.168.5.50 port 5001 connected with 192.168.5.60 port 59548
[ 4] 0.0-10.1 sec 53.5 MBytes 44.6 Mbits/sec
respbian client
root@raspberrypi:/home/pi# iperf -c 192.168.5.50
------------------------------------------------------------
Client connecting to 192.168.5.50, TCP port 5001
TCP window size: 43.8 KByte (default)
------------------------------------------------------------
[ 3] local 192.168.5.60 port 59546 connected with 192.168.5.50 port 5001
[ ID] Interval Transfer Bandwidth
[ 3] 0.0-10.0 sec 53.6 MBytes 44.9 Mbits/sec
root@raspberrypi:/home/pi# iperf -c 192.168.5.50
------------------------------------------------------------
Client connecting to 192.168.5.50, TCP port 5001
TCP window size: 43.8 KByte (default)
------------------------------------------------------------
[ 3] local 192.168.5.60 port 59547 connected with 192.168.5.50 port 5001
[ ID] Interval Transfer Bandwidth
[ 3] 0.0-10.0 sec 53.4 MBytes 44.6 Mbits/sec
root@raspberrypi:/home/pi# iperf -c 192.168.5.50
------------------------------------------------------------
Client connecting to 192.168.5.50, TCP port 5001
TCP window size: 43.8 KByte (default)
------------------------------------------------------------
[ 3] local 192.168.5.60 port 59548 connected with 192.168.5.50 port 5001
[ ID] Interval Transfer Bandwidth
[ 3] 0.0-10.0 sec 53.5 MBytes 44.7 Mbits/sec
root@raspberrypi:/home/pi#
While on osmc media center is stil down rsync confirms the speed difference.
from raspbian to the osmc, external hdd to external hdd
root@raspberrypi:# rsync -aPhv tails-i386-2.0.iso osmc@192.168.5.50:/mnt/wde4tb/za_brisati
sending incremental file list
tails-i386-2.0.iso
1.14G 100% 2.34MB/s 0:07:42 (xfr#1, to-chk=0/1)
sent 1.14G bytes received 35 bytes 2.45M bytes/sec
total size is 1.14G speedup is 1.00
from osmc to the raspbian, external hdd to external hdd
root@osmc:/mnt/wde4tb/za_brisati# rsync -aPhv tails-i386-2.0.iso pi@192.168.5.60:/mnt/wdg2tb/obrisi
sending incremental file list
tails-i386-2.0.iso
1.14G 100% 1.79MB/s 0:10:03 (xfr#1, to-chk=0/1)
sent 1.14G bytes received 35 bytes 1.85M bytes/sec
total size is 1.14G speedup is 1.00
On both raspberries RPI1 (raspbian) and RPI2 (osmc) I have installed samba. I have copied the same file 1.05 GB from raspbian to my laptop (windows 10) which was at approximatelly speed 4.15 MB/s. The same file from osmc to laptop was copied at average speed 5.30 MB/s.
I really don’t get it. 
What sort of switch are your Pi’s connected to ? Is it a managed or unmanaged switch ?
If it is a managed switch do you have Ethernet flow control enabled or disabled on the ports the Pi’s are connected to ?
Try either enabling flow control on the switch ports the Pi’s are connected to, or add the following option to /boot/cmdline.txt:
smsc95xx.turbo_mode=Y