Centos 7 更新内核上bbr

# rpm --import https://www.elrepo.org/RPM-GPG-KEY-elrepo.org
# rpm -Uvh http://www.elrepo.org/elrepo-release-7.0-2.el7.elrepo.noarch.rpm
# yum --enablerepo=elrepo-kernel install kernel-ml -y
# rpm -qa | grep kernel

设置默认启动内核
# awk -F\' '$1=="menuentry " {print i++ " : " $2}' /etc/grub2.cfg 
0 : CentOS Linux (5.4.13-1.el7.elrepo.x86_64) 7 (Core) 
1 : CentOS Linux (5.4.13-1.el7.elrepo.x86_64) 7 (Core) with debugging 
2 : CentOS Linux (3.10.0-1062.9.1.el7.x86_64) 7 (Core) 
3 : CentOS Linux (3.10.0-1062.9.1.el7.x86_64) 7 (Core) with debugging 
4 : CentOS Linux 7 (Core), with Linux 0-rescue-8cc82c5d44814ef58be1f76d8536afe

# grub2-set-default 0 
# grub2-mkconfig -o /boot/grub2/grub.cfg 
# shutdown -r now

启动BBR
# echo 'net.core.default_qdisc=fq' | tee -a /etc/sysctl.conf
# echo 'net.ipv4.tcp_congestion_control=bbr' | tee -a /etc/sysctl.conf
# sysctl -p
# sysctl net.ipv4.tcp_available_congestion_control
# sysctl -n net.ipv4.tcp_congestion_control
# lsmod | grep bbr