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From: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com>
Date: Sat, 3 Feb 2024 06:02:15 +0500
Message-ID: <CABXGCsNnUfCCYVSb_-j-a-cAdONu1r6Fe8p2OtQ5op_wskOfpw@mail.gmail.com>
Subject: =?UTF-8?Q?This_is_the_fourth_time_I=E2=80=99ve_tried_to_find_what_le?=
	=?UTF-8?Q?d_to_the_regression_of_outgoing_network_speed_and_each_time_?=
	=?UTF-8?Q?I_find_the_merge_commit_8c94ccc7cd691472461448f98e2372c75849?=
	=?UTF-8?Q?406c?=
To: Linux List Kernel Mailing <linux-kernel@vger.kernel.org>, linux-netdev@vger.kernel.org, 
	Greg KH <gregkh@linuxfoundation.org>
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Hi,
I'm trying to find the first bad commit that led to a decreased
network outgoing speed.
And every time I come to a huge merge [Merge tag 'usb-6.8-rc1' of
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb]
I have already triple-checked all my answers and speed measurements.
I don't understand where I'm making a mistake.

Let's try to figure it out together.

Input data:
Two computers connected 1Gbps link.
Both have the same hardware.
Network: RTL8125 2.5GbE Controller (rev 05)

When I copy files from one computer to another and kernel snapshot
builded from commit 296455ade1fd I have 97-110MB/sec which is almost
max speed of 1Gbps link.
When I move to commit 9d1694dc91ce I have only 66-70MB/sec which is
significantly slower.

I bisected the issue by measuring network speed on each step.
I save all results to file [1]

[1] file is attached as a zip archive.

# first bad commit: [8c94ccc7cd691472461448f98e2372c75849406c] Merge
tag 'usb-6.8-rc1' of
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb

-- 
Best Regards,
Mike Gavrilov.

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