Re: Very slow realtek 8169 ethernet performance, but only one interface, on ThinkPad T14.

[Qu Wenruo <quwenruo.btrfs@gmx.com>]

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On 2020/11/5 下午3:01, Heiner Kallweit wrote:
> On 05.11.2020 03:48, Qu Wenruo wrote:
>> Hi,
>>
>> Not sure if this is a regression or not, but just find out that after upgrading to v5.9 kernel, one of my ethernet port on my ThinkPad T14 (ryzen version) becomes very slow.
>>
>> Only *2~3* Mbps.
>>
>> The laptop has two ethernet interfaces, one needs a passive adapter, the other one is a standard RJ45.
>>
>> The offending one is the one which needs the adapter (eth0).
>> While the RJ45 one is completely fine.
>>
>> 02:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 0e)
>> 05:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 15)
>>
>> The 02:00.0 one is the affected one.
>>
>> The related dmesgs are:
>> [   38.110293] r8169 0000:02:00.0: can't disable ASPM; OS doesn't have ASPM control
>> [   38.126069] libphy: r8169: probed
>> [   38.126250] r8169 0000:02:00.0 eth0: RTL8168ep/8111ep, 00:2b:67:b3:d9:20, XID 502, IRQ 105
>> [   38.126252] r8169 0000:02:00.0 eth0: jumbo features [frames: 9194 bytes, tx checksumming: ko]
>> [   38.126294] r8169 0000:05:00.0: can't disable ASPM; OS doesn't have ASPM control
>> [   38.126300] r8169 0000:05:00.0: enabling device (0000 -> 0003)
>> [   38.139355] libphy: r8169: probed
>> [   38.139523] r8169 0000:05:00.0 eth1: RTL8168h/8111h, 00:2b:67:b3:d9:1f, XID 541, IRQ 107
>> [   38.139525] r8169 0000:05:00.0 eth1: jumbo features [frames: 9194 bytes, tx checksumming: ko]
>> [   42.120935] Generic FE-GE Realtek PHY r8169-200:00: attached PHY driver [Generic FE-GE Realtek PHY] (mii_bus:phy_addr=r8169-200:00, irq=IGNORE)
>> [   42.247646] r8169 0000:02:00.0 eth0: Link is Down
>> [   42.280799] Generic FE-GE Realtek PHY r8169-500:00: attached PHY driver [Generic FE-GE Realtek PHY] (mii_bus:phy_addr=r8169-500:00, irq=IGNORE)
>> [   42.477616] r8169 0000:05:00.0 eth1: Link is Down
>> [   76.479569] r8169 0000:02:00.0 eth0: Link is Up - 1Gbps/Full - flow control rx/tx
>> [   91.271894] r8169 0000:02:00.0 eth0: Link is Down
>> [   99.873390] r8169 0000:02:00.0 eth0: Link is Up - 1Gbps/Full - flow control rx/tx
>> [   99.878938] r8169 0000:02:00.0 eth0: Link is Down
>> [  102.579290] r8169 0000:02:00.0 eth0: Link is Up - 1Gbps/Full - flow control rx/tx
>> [  185.086002] r8169 0000:02:00.0 eth0: Link is Down
>> [  392.884584] r8169 0000:02:00.0 eth0: Link is Up - 1Gbps/Full - flow control rx/tx
>> [  392.891208] r8169 0000:02:00.0 eth0: Link is Down
>> [  395.889047] r8169 0000:02:00.0 eth0: Link is Up - 1Gbps/Full - flow control rx/tx
>> [  406.670738] r8169 0000:02:00.0 eth0: Link is Down
>>
>> Really nothing strange, even it negotiates to 1Gbps.
>>
>> But during iperf3, it only goes up to miserable 3Mbps.
>>
>> Is this some known bug or something special related to the passive adapter?
>>
>> Since the adapter is passive, and hasn't experience anything wrong for a long time, I really doubt that.
>>
>> Thanks,
>> Qu
>>
>>
> Thanks for the report. From which kernel version did you upgrade?

Tested back to v5.7, which still shows the miserable performance.

So I guess it could be a faulty adapter?

> Please test
> with the prior kernel version and report behavior (link stability and speed).
> Under 5.9, does ethtool -S eth0 report packet errors?
> 
Nope, no tx/rx_errors, no missed/aborted/underrun.

Adding that the adapter is completely passive (no chip, just converting
RJ45 pins to the I shaped pins), I'm not sure that the adapter itself
can fail.

THanks,
Qu


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