Enable BBR on Arch/Manjaro

BBR is a new congestion control algorithm developed at Google, which was supported in Linux 4.9.

Arch may be needed to switch to testing branch to temporarily install Linux kernel 4.9.

pacman-mirrors -g -b testing

Test if BBR is included in your installed kernel (early version on Manjaro did not config BBR)

modprobe tcp_bbr

lsmod | grep bbr

Modify /etc/sysctl.d/*.conf to set these values (remove existed config which set to different values):

net.core.default_qdisc=fq
net.ipv4.tcp_congestion_control=bbr

sysctl -p or reboot, check sysctl net.ipv4.tcp_congestion_control.