GbE Ethernet Port Issue Data Gathering Statistics Intel

[benjanyan]

1) 201-A64-DB110-02
    A64-DB-v1.1 2G
    C160358 04.11
2) RTL8211E  G2K40P2  GG10B
3) Asus N56U (Realtek RTL8367M chip for switch)
4) Not modded.
5) N/A
6) Run a Samba server on it so Gb Ethernet is nice (although I am of course limited by USB2.0 then)
7) PINE64 works at acceptable levels most of the time over Gb. Network slows to almost nothing occasionally. More explanation in my post here.

Code:

Linux aoba 3.10.102-2-pine64-longsleep #66 SMP PREEMPT Sat Jul 16 10:53:13 CEST 2016 aarch64 GNU/Linux
yuki_n@aoba:~$ sudo ifconfig eth0
eth0      Link encap:Ethernet  HWaddr 36:c9:e3:f1:b8:05
         inet addr:192.168.20.7  Bcast:192.168.20.255  Mask:255.255.255.0
         inet6 addr: fe80::34c9:e3ff:fef1:b805/64 Scope:Link
         UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
         RX packets:5666217 errors:0 dropped:0 overruns:0 frame:0
         TX packets:6714105 errors:0 dropped:0 overruns:0 carrier:0
         collisions:0 txqueuelen:1000
         RX bytes:6494935317 (6.0 GiB)  TX bytes:6641734676 (6.1 GiB)
         Interrupt:114

yuki_n@aoba:~$ sudo ethtool eth0
Settings for eth0:
       Supported ports: [ TP MII ]
       Supported link modes:   10baseT/Half 10baseT/Full
                               100baseT/Half 100baseT/Full
                               1000baseT/Half 1000baseT/Full
       Supported pause frame use: No
       Supports auto-negotiation: Yes
       Advertised link modes:  10baseT/Half 10baseT/Full
                               100baseT/Half 100baseT/Full
                               1000baseT/Half 1000baseT/Full
       Advertised pause frame use: No
       Advertised auto-negotiation: Yes
       Speed: 1000Mb/s
       Duplex: Full
       Port: MII
       PHYAD: 0
       Transceiver: external
       Auto-negotiation: on
       Link detected: yes
yuki_n@aoba:~$ iperf -c mashiro
------------------------------------------------------------
Client connecting to mashiro, TCP port 5001
TCP window size: 22.5 KByte (default)
------------------------------------------------------------
[  3] local 192.168.20.7 port 51133 connected with 192.168.20.6 port 5001
[ ID] Interval       Transfer     Bandwidth
[  3]  0.0-10.0 sec   611 MBytes   512 Mbits/sec
yuki_n@aoba:~$

Router reports (note FC OFF and dot3StatsFCSErrors which differ to other Gbit ethernet devices on my network) :

Code:

Port Link            : 1000 Mbps, Full Duplex, FC OFF

MIB Counters
----------------------------------------
ifInOctets            : 4483548236
ifOutOctets            : 73064230
etherStatsMcastPkts        : 36667
etherStatsBcastPkts        : 4463
etherStatsFragments        : 0
etherStatsDropEvents        : 0
etherStatsUndersizePkts        : 0
etherStatsOversizePkts        : 0
etherStatsCollisions        : 0
dot3StatsFCSErrors        : 6840
dot3StatsSymbolErrors        : 0
dot3ControlInUnknownOpcodes    : 0
dot3InPauseFrames        : 0
dot3OutPauseFrames        : 0