Arch Linux

rgorrell

Member

From: Gorrell

Registered: 2012-07-15

Posts: 9

[SOLVED] Wired internet speed discrepancy - Arch vs. Ubuntu...

Hi all,

I'm seeing a speed discrepancy between a dual boot Arch/Windows install that I'm having trouble sorting and would appreciate some advice.  Speedtest.net is showing 50 Mbps down and 120 Mbps up on my Arch install.  The Windows install gets 900 Mbps both up and down.  I also get 900 Mbps up and down on Ubuntu 18.04 running from a USB stick.  I have run iperf to another linux machine on my LAN and get 900+ Mbps both to and from the dual boot machine when running Arch.  I'm currently using a TP-Link UE300 USB 3.0 to Gigabit ethernet adapter, but have seen the same problem with the built in Gigabit NIC.  The driver appears to be loaded properly as dmesg reports the same r8152 driver running on both Arch and Ubuntu.  Given the good speeds in Ubuntu and Windows it's likely something I've done wrong in Arch, but I haven't been able to figure it out.  I appreciate any help.

Last edited by rgorrell (2018-08-10 02:28:22)

circleface

Member

Registered: 2012-05-26

Posts: 639

Re: [SOLVED] Wired internet speed discrepancy - Arch vs. Ubuntu...

You need to set net.ipv4.tcp_ecn=0 in sysctl.  This is a throttling system that has just been enabled by default in systemd.

# sysctl net.ipv4.tcp_ecn=0

rgorrell

Member

From: Gorrell

Registered: 2012-07-15

Posts: 9

Re: [SOLVED] Wired internet speed discrepancy - Arch vs. Ubuntu...

You nailed it!  I've got 900+ Mbps again with Arch!

I see from a Forum search that the default was changed with systemd-239.0.2.

Thank you circleface!  Will mark as solved.

brebs

Member

Registered: 2007-04-03

Posts: 3,742

Re: [SOLVED] Wired internet speed discrepancy - Arch vs. Ubuntu...

Sounds like Internet speed is lower than LAN speed, which is quite normal.

Rather than "I get 900 Mbps", explain in more detail how you are performing these speed tests.