Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Subject: Re: Very slow realtek 8169 ethernet performance, but only one
 interface, on ThinkPad T14.
To:     Qu Wenruo <quwenruo.btrfs@gmx.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        netdev@vger.kernel.org
References: <57f16fe7-2052-72cc-6628-bbb04f146ce0@gmx.com>
From:   Heiner Kallweit <hkallweit1@gmail.com>
Message-ID: <7ee6a86c-5aca-3931-73cc-2ab72d8dd8a7@gmail.com>
Date:   Thu, 5 Nov 2020 08:01:49 +0100
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101
 Thunderbird/78.4.0
MIME-Version: 1.0
In-Reply-To: <57f16fe7-2052-72cc-6628-bbb04f146ce0@gmx.com>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Precedence: bulk

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? Please test
with the prior kernel version and report behavior (link stability and speed).
Under 5.9, does ethtool -S eth0 report packet errors?