ELRepo kernel

The ELRepo project provides a version of the most recent 'stable' Linux kernel in rpm form that is easy to install on RHEL/CentOS based hosts.

In particular, this kernel includes FQ-based pacing, and BBR TCP for CentOS 6 and 7. BBR TCP is included starting with CentOS 8. 

To install the latest stable kernel on a CentOS host, do the following:

  rpm --import   
  # for CentOS 6
  rpm -Uvh  
  # for CentOS 7
  rpm -Uvh 
  # then to install kernel
  yum -y --enablerepo=elrepo-kernel install kernel-ml

If you need to build device drivers, also install this one:

yum -y --enablerepo=elrepo-kernel install kernel-ml-devel

Then configure Grub to use the new kernel:

For CentOS 6

vi /boot/grub/grub.conf 
  default=0 # change default to 0 
  fallback=1 # add this one

For CentOS 7

grub2-set-default 0
grub2-install /dev/sda grub2-mkconfig -o /boot/grub2/grub.cfg

Then reboot.

To enable FQ, add this to /etc/sysctl.conf:

     net.core.default_qdisc = fq

To enable BBR TCP, do:

     /sbin/modprobe tcp_bbr