Linux 4.2 Offers Performance Improvements For Non-Transparent Bridging
Written by Michael Larabel in Linux Kernel on 5 July 2015 at 09:01 AM EDT. Add A Comment
One of the later pull requests for the Linux 4.2 kernel merge window is a big rework to the NTB (Non-Transparent Bridge) core code.

The Non-Transparent Bridge code is undergoing a big rework that has "already produced some significant performance improvements", according to its code maintainer Jon Mason. For those unfamiliar with NTB, it's described by the in-kernel documentation, "NTB (Non-Transparent Bridge) is a type of PCI-Express bridge chip that connects the separate memory systems of two computers to the same PCI-Express fabric. Existing NTB hardware supports a common feature set, including scratchpad registers, doorbell registers, and memory translation windows." Or explained simply by the Intel Xeon documentation that received the NTB support, "Non-Transparent Bridge (NTB) enables high speed connectivity
between one Intel Xeon Processor-based platform to another (or other IA or non-IA platform via the PCIe interface)."

With the performance improvements and other NTB code changes come NUMA enablement, support for using CPU memcpy than asyncdma, and other tweaks. Those wishing to learn more about the NTB improvements for Linux 4.2 can view the details of this Git pull.
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