HiSilicon Kunpeng PCIe Tune and Trace (PTT)
A PCIe performance tracing and tuning block built into the root complex of HiSilicon's Kunpeng 920 and 930 ARM server SoCs, used in Huawei TaiShan servers. It lets administrators capture PCIe transaction traces and tune link behaviour for performance analysis on those machines, which are still being sold in 2025.
recommendation
It should stay in the kernel because the hardware is current — Huawei still sells Kunpeng 920-based TaiShan servers in 2025 — and the driver continues to receive substantive upstream maintenance, with the most recent meaningful change landing in May 2024. No other driver provides the same PCIe tracing and tuning function for this silicon, so removing it would leave Kunpeng server operators without a way to use the feature. Real-world deployment is modest since this is a niche performance-analysis block on Huawei ARM servers.
repository signals
sources
- kernel.org
Upstream documentation identifies this as the HiSilicon PCIe Tune and Trace device and states it exists on Kunpeng 930 SoC PCIe root complexes.
- git.kernel.org
The driver received a substantive upstream maintenance change on 2024-05-02, showing recent non-removal activity.
- git.kernel.org
The driver was added upstream in 2022 as support for HiSilicon PCIe Tune and Trace trace functionality, confirming it is a relatively new driver rather than legacy carry-over.
- hisilicon.com
HiSilicon's product page shows Kunpeng 920 as a server CPU family with PCIe 4.0 I/O, placing this driver in current server hardware rather than only historical devices.
- support.huawei.com
Huawei's TaiShan 200 server specifications list Kunpeng 920 processor configurations in current product documentation, supporting that systems using this platform were still being marketed in 2025.
codex reasoning notes (technical)
Not an early-exit case: this directory contains a PCI driver (hisi_ptt.c plus Kconfig/Makefile and module entry points). Local shell inspection of Kconfig, source, and Documentation/trace/hisi-ptt.rst identified the hardware as HiSilicon PCIe Tune and Trace on Kunpeng SoCs; the kernel.org doc URL is canonical recall from that local doc path. Local `git log` (using `git -c safe.directory=...`) showed active substantive maintenance through 2024-05-02 and no sign of a removal trajectory; the cited git.kernel.org commit URLs were constructed from those locally observed commit IDs using canonical recall. Web search found official HiSilicon/Huawei product pages showing Kunpeng 920/TaiShan server availability, so hardware appears still sold in 2025, but deployment is likely low because this is a niche Huawei ARM server PMU/tracing block. No natural replacement driver exists for the same hardware-specific tracing/tuning function.