[PATCH v4 1/4] docs: perf: Add description for Synopsys DesignWare PCIe PMU driver
From: Shuai Xue <xueshuai@linux.alibaba.com>
Date: 2023-05-16 13:01:33
Also in:
linux-pci, lkml
Subsystem:
documentation, synopsys designware pcie pmu driver, the rest · Maintainers:
Jonathan Corbet, Shuai Xue, Jing Zhang, Linus Torvalds
Alibaba's T-Head Yitan 710 SoC is built on Synopsys' widely deployed and silicon-proven DesignWare Core PCIe controller which implements PMU for performance and functional debugging to facilitate system maintenance. Document it to provide guidance on how to use it. Signed-off-by: Shuai Xue <xueshuai@linux.alibaba.com> --- .../admin-guide/perf/dwc_pcie_pmu.rst | 61 +++++++++++++++++++ Documentation/admin-guide/perf/index.rst | 1 + 2 files changed, 62 insertions(+) create mode 100644 Documentation/admin-guide/perf/dwc_pcie_pmu.rst
diff --git a/Documentation/admin-guide/perf/dwc_pcie_pmu.rst b/Documentation/admin-guide/perf/dwc_pcie_pmu.rst
new file mode 100644
index 000000000000..0672e959ebe4
--- /dev/null
+++ b/Documentation/admin-guide/perf/dwc_pcie_pmu.rst@@ -0,0 +1,61 @@ +====================================================================== +Synopsys DesignWare Cores (DWC) PCIe Performance Monitoring Unit (PMU) +====================================================================== + +DesignWare Cores (DWC) PCIe PMU +=============================== + +To facilitate collection of statistics, Synopsys DesignWare Cores PCIe +controller provides the following two features: + +- Time Based Analysis (RX/TX data throughput and time spent in each + low-power LTSSM state) +- Lane Event counters (Error and Non-Error for lanes) + +The PMU is not a PCIe Root Complex integrated End Point (RCiEP) device but +only register counters provided by each PCIe Root Port. + +Time Based Analysis +------------------- + +Using this feature you can obtain information regarding RX/TX data +throughput and time spent in each low-power LTSSM state by the controller. + +The counters are 64-bit width and measure data in two categories, + +- percentage of time does the controller stay in LTSSM state in a + configurable duration. The measurement range of each Event in Group#0. +- amount of data processed (Units of 16 bytes). The measurement range of + each Event in Group#1. + +Lane Event counters +------------------- + +Using this feature you can obtain Error and Non-Error information in +specific lane by the controller. + +The counters are 32-bit width and the measured event is select by: + +- Group i +- Event j within the Group i +- and Lane k + +Some of the event counters only exist for specific configurations. + +DesignWare Cores (DWC) PCIe PMU Driver +======================================= + +This driver add PMU devices for each PCIe Root Port. And the PMU device is +named based the BDF of Root Port. For example, + + 30:03.0 PCI bridge: Device 1ded:8000 (rev 01) + +the PMU device name for this Root Port is dwc_rootport_3018. + +Example usage of counting PCIe RX TLP data payload (Units of 16 bytes):: + + $# perf stat -a -e dwc_rootport_3018/Rx_PCIe_TLP_Data_Payload/ + +average RX bandwidth can be calculated like this: + + PCIe TX Bandwidth = PCIE_TX_DATA * 16B / Measure_Time_Window
diff --git a/Documentation/admin-guide/perf/index.rst b/Documentation/admin-guide/perf/index.rst
index 9de64a40adab..11a80cd28a2e 100644
--- a/Documentation/admin-guide/perf/index.rst
+++ b/Documentation/admin-guide/perf/index.rst@@ -19,5 +19,6 @@ Performance monitor support arm_dsu_pmu thunderx2-pmu alibaba_pmu + dwc_pcie_pmu nvidia-pmu meson-ddr-pmu
--
2.20.1.12.g72788fdb
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