Linux 5.8 Networking Changes Include Introducing Cable Testing Infrastructure

Written by Michael Larabel in Linux Networking on 4 June 2020 at 04:36 PM EDT. Add A Comment
David Miller on Tuesday sent in all of the networking subsystem updates for the Linux 5.8 kernel and there is a lot in store.

Among the many networking changes as usual are the following new items for Linux 5.8:

- A network cable test infrastructure has been added to the kernel and initially supported by the Marvell 1G PHY driver. This is intended for helping to figure out if a cable may be shorted, broken, not plugged in on the opposing end, or similar issues. This diagnostics support requires PHY support with some even being able to estimate how far along a cable fault may be on the wire. With Linux 5.8 this necessary infrastructure is in place but for now just the Marvell PHY driver is supported. Infrastructure is added to Ethtool and phylib for initiating such tests.

- Enabling Media Redundancy Protocol (MRP) support within the kernel's bridging code. The IEC-defined Media Redundancy Protocol allows rings of Ethernet swtiches to overcome any single failure with recovery time faster and is predomindantly used at this point within industrial Ethernet applications.

- The Intel IGC driver now has partial generic segmentation offload (GSO) support. As explained from the patch, "What is effectively does is take advantage of certain traits of TCP and tunnels so that instead of having to rewrite the packet headers for each segment only in the inner-most transport header and possible the outer-most network header need to be updated. This allows devices that do not support tunnel offload or tunnels offloads with checksum to still make use of segmentation."

- Thanks to Facebook is BPF iterator support for kernel data. This offers (e)BPF programs more flexibility for in-kernel aggregation of data and faster than iterating through procfs or other interfaces.

- Cleanups and improvements to the common Realtek r8169 driver.

- Optimizations to the sch_fq scheduler.

- RISC-V BPF just-in-time (JIT) optimizations.

- A performance improvement for the Freescale Ethernet driver (FEC).

- Support for Marvell/Aquantia Atlantic A2 NICs.

More details on the networking subsystem activity via this pull request that adds 152k lines of new code while removing 46k lines of existing code, or just over 100k lines of new code as a result of all the activity.
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Michael Larabel is the principal author of and founded the site in 2004 with a focus on enriching the Linux hardware experience. Michael has written more than 20,000 articles covering the state of Linux hardware support, Linux performance, graphics drivers, and other topics. Michael is also the lead developer of the Phoronix Test Suite, Phoromatic, and automated benchmarking software. He can be followed via Twitter, LinkedIn, or contacted via

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