With the release of kernel-xen version 4.9.40, I have enabled CONFIG_TCP_CONG_BBR. This adds support for using BBR to improve the throughput from your servers (mostly web servers) to your clients.
If you run my kernel-xen package on your Xen guests, you can also take advantage of this new feature.
To enable, ensure you are running kernel-xen version 4.9.40 or above, then create a file called /etc/sysctl.d/enable-bbr.conf containing:
You can activate this by typing:
$ sysctl -p
The changes will automatically apply at the next system boot.
To read more about BBR and why it makes such a difference, head on over to acmqueue for a far more in-depth analysis than I could provide.