Posted to the Linux networking mailing list on Wednesday were the latest patches for enabling the Homa transport protocol. Homa is the clean-sheet design aiming to become an alternative to TCP within data centers and capable of offering 10~100x reductions in tail latency for short messages.
The v16 patches for the Linux networking subsystem’s Homa implementation are now out for review as this code continues striving toward the mainline kernel. For those that haven’t explored prior versions of the Homa Linux patches or the project’s documentation, it’s self-described as:
“Homa is an alternative to TCP for use in datacenter environments. It provides 10-100x reductions in tail latency for short messages relative to TCP. Its benefits are greatest for mixed workloads containing both short and long messages running under high network loads. Homa is not API-compatible with TCP: it is connectionless and message-oriented (but still reliable and flow-controlled). Homa’s new API not only contributes to its performance gains, but it also eliminates the massive amount of connection state required by TCP for highly connected datacenter workloads (Homa uses ~ 1 socket per application, whereas TCP requires a separate socket for each peer).”
The Homa project site itself is hosted here for those interested in the broader Homa network protocol effort. Homa has been in the works for several years by engineers from Stanford and MIT.
The HomaModule GitHub repository has been tracking the progress of this Linux kernel implementation since its inception in 2019. The v16 kernel patches for Homa introduce the new “HOMAIOCINFO” information ioctl and make a number of other changes for improving the code. We’ll see how this round of code review goes for a better idea of when Homa may be potentially ready for the mainline Linux kernel.
