What networking changes and broader developments accompanied the Linux 7.3 merge on August 20, 2026—including BIG TCP support for VXLAN and Geneve UDP overlay tunnels, its throughput benefits under standard MTU and disabled offload conditions, reduced RTNL contention and faster p

The net-next-7.3 pull brought both data-path scaling work and a striking maintainer response to AI-driven patch volume: use multiple frontier models for first-pass reviews, while retaining human judgment for subtle concurrency and hardware-recovery problems. These were merge-window changes, not yet a released Linux 7.3 kernel.

• Overlay performance: BIG TCP now works through VXLAN and Geneve UDP tunnels, allowing the stack to handle payloads above 64 KiB internally and segment them through GSO/TSO rather than transmitting oversized wire packets.

  • In the reported

    netperf TCP_STREAM

    tests, VXLAN rose 14.9% at standard MTU (34.44 → 39.56 Gbit/s) and 34.7% with tunnel hardware offload disabled (21.82 → 29.39 Gbit/s). Geneve rose 9.4% at standard MTU (37.39 → 40.89 Gbit/s). These are configuration-specific results, not a general 7.3 speedup guarantee.
  • Benefits depend on end-to-end configuration—including gso_max_size/gro_max_size, NIC capabilities, offload state, MTU, tunnel type, and workload.

• Routing-rule scalability: IPv4/IPv6 FIB-rule add/delete operations were moved away from broad RTNL serialization toward per-fib_rules_ops mutex protection where possible. RTNL remains necessary for some cases, including the first IPv4 rule’s fib_unmerge() path.

  • A synthetic test creating 4,096 namespaces and inserting 1,024 rules into each in parallel fell from 22.752 to 0.918 seconds for IPv4—about 24.8×—and from 35.181 to 1.214 seconds for IPv6—about 29.0×. That measures extreme parallel namespace contention, not normal container-startup performance.

• AI patch flood: Networking maintainer Jakub Kicinski counted 632 net and 648 net-next patches, and estimated that one-third to one-half of net-next were AI-driven, low-priority fixes, cleanups, or clarifications—roughly 216–324 patches. He and Paolo Abeni described themselves as “completely overwhelmed.”

• AI as a countermeasure, not a replacement: Meta supplied budget/access for multiple frontier models to review each patch, intended to reduce individual-model hallucinations. The planned automation targets Patchwork management, common process feedback, commit-message editing, and possibly applying patches already reviewed by trusted people.

  • Maintainers explicitly do not see this as sufficient for rare, race-prone paths—such as PCIe errors and timeouts—where API behavior and recovery sequencing still need human scrutiny.

• Drivers and protocol work:

  • Wireless gained the initial Morse Micro mm81x Wi‑Fi HaLow driver, for USB and SDIO devices, and NXPWIFI as a new NXP wireless driver; MLO work also continued.
  • Wired work includes the initial skeleton Intel iXD driver, intended for Intel Control Plane PIC Function support on E2100-and-later IPUs/FNICs, plus initial CXL support for AMD/Solarflare NICs and AMD Pensando firmware-flashing support.
  • MPTCP now has a last-resort out-of-order-queue pruning mechanism under extreme memory pressure, aimed at recovery/retransmission rather than normal throughput.
  • AF_UNIX SCM_RIGHTS gains improved reporting when an LSM rejects particular file descriptors: with SO_RIGHTS_NOTRUNC, the receiver can identify the rejected descriptor and its errno instead of losing the remainder of the array at the first failure.

• Schedule and availability: The first 7.3 release candidate was expected around August 30, with a stable kernel projected for late October, subject to the normal release cycle. Most users of fixed-release distributions should expect a substantially longer wait because distributions select, backport, test, and ship kernels on their own schedules. Rolling distributions can package it earlier; CachyOS is a plausible early adopter, but there is no evidence here of a committed 7.3 adoption date. Its August image was still shipping Linux 7.1.