Speed ​​drop, network card, debian?

Question

Debian

Good day to all. I ran into a problem, a drop in speed, on one of the two network cards, to several Kbps from 100Mbps. I don’t even know where to dig, tell me please, I already tortured it, it doesn’t work)))
It helps /etc/init.d/networking force-reload, well, or reboot. It can work normally all day, or it can go crazy 20 times a day.
uname

Linux debian 3.16.0-4-amd64 #1 SMP Debian 3.16.7-ckt11-1+deb8u6 (2015-11-09) x86_64 GNU/Linux

lspci | grep Eth

07:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 06)
09:01.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL-8100/8101L/8139 PCI Fast Ethernet Adapter (rev 10)
09:02.0 Ethernet controller: VIA Technologies, Inc. VT6105/VT6106S [Rhine-III] (rev 8b)

SYSLOG

Jan 31 14:39:04 debian kernel: [11514.140084] irq 16: nobody cared (try booting with the "irqpoll" option)
Jan 31 14:39:04 debian kernel: [11514.140132] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.16.0-4-amd64 #1 Debian 3.16.7-ckt11-1+deb8u6
Jan 31 14:39:04 debian kernel: [11514.140135] Hardware name: System manufacturer System Product Name/P8Z68-V LE, BIOS 0401 06/21/2011
Jan 31 14:39:04 debian kernel: [11514.140137]  ffff88023641b4c4 ffffffff8150b4e5 ffff88023641b400 ffffffff810bd21d
Jan 31 14:39:04 debian kernel: [11514.140141]  ffff88023641b400 0000000000000010 0000000000000000 ffffffff810bd741
Jan 31 14:39:04 debian kernel: [11514.140144]  0000000000000000 0000000000000000 0000000000000010 0000000000000000
Jan 31 14:39:04 debian kernel: [11514.140147] Call Trace:
Jan 31 14:39:04 debian kernel: [11514.140149]  <IRQ>  [<ffffffff8150b4e5>] ? dump_stack+0x41/0x51
Jan 31 14:39:04 debian kernel: [11514.140162]  [<ffffffff810bd21d>] ? __report_bad_irq+0x2d/0xc0
Jan 31 14:39:04 debian kernel: [11514.140166]  [<ffffffff810bd741>] ? note_interrupt+0x241/0x290
Jan 31 14:39:04 debian kernel: [11514.140170]  [<ffffffff810baf61>] ? handle_irq_event_percpu+0xa1/0x190
Jan 31 14:39:04 debian kernel: [11514.140174]  [<ffffffff810bb088>] ? handle_irq_event+0x38/0x60
Jan 31 14:39:04 debian kernel: [11514.140177]  [<ffffffff810be283>] ? handle_fasteoi_irq+0x83/0x150
Jan 31 14:39:04 debian kernel: [11514.140183]  [<ffffffff810150cd>] ? handle_irq+0x1d/0x30
Jan 31 14:39:04 debian kernel: [11514.140186]  [<ffffffff815144d9>] ? do_IRQ+0x49/0xe0
Jan 31 14:39:04 debian kernel: [11514.140190]  [<ffffffff8151232d>] ? common_interrupt+0x6d/0x6d
Jan 31 14:39:04 debian kernel: [11514.140191]  <EOI>  [<ffffffff8108ad0d>] ? __hrtimer_start_range_ns+0x1cd/0x390
Jan 31 14:39:04 debian kernel: [11514.140200]  [<ffffffff813de01f>] ? cpuidle_enter_state+0x4f/0xc0
Jan 31 14:39:04 debian kernel: [11514.140203]  [<ffffffff813de018>] ? cpuidle_enter_state+0x48/0xc0
Jan 31 14:39:04 debian kernel: [11514.140208]  [<ffffffff810a7f78>] ? cpu_startup_entry+0x2f8/0x400
Jan 31 14:39:04 debian kernel: [11514.140211]  [<ffffffff81903071>] ? start_kernel+0x492/0x49d
Jan 31 14:39:04 debian kernel: [11514.140214]  [<ffffffff81902a04>] ? set_init_arg+0x4e/0x4e
Jan 31 14:39:04 debian kernel: [11514.140217]  [<ffffffff81902120>] ? early_idt_handlers+0x120/0x120
Jan 31 14:39:04 debian kernel: [11514.140220]  [<ffffffff8190271f>] ? x86_64_start_kernel+0x14d/0x15c
Jan 31 14:39:04 debian kernel: [11514.140222] handlers:
Jan 31 14:39:04 debian kernel: [11514.140251] [<ffffffffa0122030>] rtl8139_interrupt [8139too]
Jan 31 14:39:04 debian kernel: [11514.140285] Disabling IRQ #16

ethtool

Settings for eth2:
        Supported ports: [ TP MII ]
        Supported link modes:   10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
        Supported pause frame use: No
        Supports auto-negotiation: Yes
        Advertised link modes:  10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
        Advertised pause frame use: No
        Advertised auto-negotiation: Yes
        Link partner advertised link modes:  10baseT/Half 10baseT/Full
                                             100baseT/Half 100baseT/Full
        Link partner advertised pause frame use: Symmetric
        Link partner advertised auto-negotiation: Yes
        Speed: 100Mb/s
        Duplex: Full
        Port: MII
        PHYAD: 32
        Transceiver: internal
        Auto-negotiation: on
        Supports Wake-on: pumbg
        Wake-on: d
        Current message level: 0x00000007 (7)
                               drv probe link
        Link detected: yes

ifconfig (specifically eth2)

eth1      Link encap:Ethernet  HWaddr f4:6d:04:64:c0:39
          inet addr:10.0.0.2  Bcast:10.0.0.255  Mask:255.255.255.0
          inet6 addr: fe80::f66d:4ff:fe64:c039/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:3495 errors:0 dropped:0 overruns:0 frame:0
          TX packets:2225 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:324798 (317.1 KiB)  TX bytes:691369 (675.1 KiB)

eth2      Link encap:Ethernet  HWaddr f8:d1:11:05:49:1e
          inet addr:192.168.1.2  Bcast:192.168.1.255  Mask:255.255.255.0
          inet6 addr: fe80::fad1:11ff:fe05:491e/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:63171 errors:0 dropped:4 overruns:0 frame:0
          TX packets:190690 errors:0 dropped:0 overruns:17 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:6300400 (6.0 MiB)  TX bytes:275987864 (263.2 MiB)

lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

Solution
In general, I didn’t really find anything, I tried everything with wires, routers, cards and other things. Adding just irqpoll didn't help. In general, I used noirqdebug, only this helped with constant falls, after 2 days everything is stable.

etc/default/grub 
GRUB_CMDLINE_LINUX_DEFAULT="quiet noirqdebug irqpoll"

Answer 1

Это может быть кабель или коммутатор.
Воткните в этот кабель в другой комп, заведомо рабочий и погоняйте.
Если другой комп нормально себя ведет - значит дело в адаптере - меняйте.
Сбойные сетевые адаптеры порой ведут себя очень странно.