# yum update

# rpm --import https://www.elrepo.org/RPM-GPG-KEY-elrepo.org
# rpm -Uvh http://www.elrepo.org/elrepo-release-7.0-3.el7.elrepo.noarch.rpm
# yum --enablerepo=elrepo-kernel install kernel-ml -y

# egrep ^menuentry /etc/grub2.cfg | cut -f 2 -d \'
# grub2-set-default 0
# reboot

# uname -r

# vim /etc/sysctl.conf
net.core.default_qdisc = fq
net.ipv4.tcp_congestion_control = bbr
# sysctl -p

# sysctl net.ipv4.tcp_available_congestion_control
#或
# lsmod | grep bbr