40% Speed Bump? Linux Kernel 6.8 Redefines TCP Performance

The Linux Kernel 6.8 has received pivotal updates that markedly enhance the performance of the TCP stack, potentially increasing efficiency in handling multiple parallel TCP connections by up to 40%.

This enhancement became feasible following the meticulous optimization of the network stack’s data structures (socks, netdev, netns, mibs). Originally, variables in these structures were arranged haphazardly due to historical reasons. Their re-engineering, considering the nuances of processor cache characteristics, has significantly boosted the TCP stack’s efficiency, particularly in scenarios involving a large number of simultaneous connections.

In addition to TCP optimization, the kernel now supports new networking devices, including Texas Instrument’s DP83TG720S and Octeon CN10K network adapters, as well as new Bluetooth chipsets such as the QCA2066.

Moreover, the update has refined drivers for network adapters from manufacturers like Intel, Mellanox, and Broadcom. It has implemented support for novel features, including hardware-based packet mirroring and accelerated VLAN processing.

Furthermore, the kernel has been augmented with enhancements in the BPF subsystem: an expanded verifier, implemented support for metadata in XDP, and rectified errors in interaction with the kernel’s integrity control mechanism.