Recent TCP Enhancements

Recently (2013-2016)  there have been a number of enhancements to the Linux TCP code that potentially can have a large impact on TCP throughput. A number of these enhancements are described in this talk:

• David Miller NetDev KeyNote, Feb 2015)

The most important changes include:

• packet pacing
• dynamic TSO sizing
• TCP small queues

• BBR TCP (first available 2016 in the 4.9 kernel)

Many of these enhancements became widely available starting with RHEL/CentOS 7.2 and Debian 8.

BBR TCP is available starting in RHEL/CentOS 8.0, Debian 9, and Ubuntu 17. To run BBR TCP on a RHEL/CentOS 7.x host, try using the latest 'stable' kernel from kernel.org. The easiest way to install this kernel is to use the ELRepo kernel. 

For more information on recent Linux network performance enhancements for 100G+ flows, see our Linux 6.x page.