Commit 96a37ec9 authored by Krishna chaitanya chundru's avatar Krishna chaitanya chundru Committed by Will Deacon
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Documentation: dwc_pcie_pmu: Update bdf to sbdf 



Update document to reflect the driver change to use sbdf instead
of bdf alone.

Signed-off-by: default avatarKrishna chaitanya chundru <quic_krichai@quicinc.com>
Reviewed-by: default avatarYicong Yang <yangyicong@hisilicon.com>
Link: https://lore.kernel.org/r/20240816-dwc_pmu_fix-v2-2-198b8ab1077c@quicinc.com


Signed-off-by: default avatarWill Deacon <will@kernel.org>
parent e6693885

Documentation/admin-guide/perf/dwc_pcie_pmu.rst

+8 −8
Original line number Diff line number Diff line
@@ -46,16 +46,16 @@ Some of the events only exist for specific configurations. 
DesignWare Cores (DWC) PCIe PMU Driver

=======================================



This driver adds PMU devices for each PCIe Root Port named based on the BDF of

This driver adds PMU devices for each PCIe Root Port named based on the SBDF of

the Root Port. For example,



    30:03.0 PCI bridge: Device 1ded:8000 (rev 01)

    0001:30:03.0 PCI bridge: Device 1ded:8000 (rev 01)



the PMU device name for this Root Port is dwc_rootport_3018.

the PMU device name for this Root Port is dwc_rootport_13018.



The DWC PCIe PMU driver registers a perf PMU driver, which provides

description of available events and configuration options in sysfs, see

/sys/bus/event_source/devices/dwc_rootport_{bdf}.

/sys/bus/event_source/devices/dwc_rootport_{sbdf}.



The "format" directory describes format of the config fields of the

perf_event_attr structure. The "events" directory provides configuration
@@ -66,16 +66,16 @@ The "perf list" command shall list the available events from sysfs, e.g.:: 


    $# perf list | grep dwc_rootport

    <...>

    dwc_rootport_3018/Rx_PCIe_TLP_Data_Payload/        [Kernel PMU event]

    dwc_rootport_13018/Rx_PCIe_TLP_Data_Payload/        [Kernel PMU event]

    <...>

    dwc_rootport_3018/rx_memory_read,lane=?/               [Kernel PMU event]

    dwc_rootport_13018/rx_memory_read,lane=?/               [Kernel PMU event]



Time Based Analysis Event Usage

-------------------------------



Example usage of counting PCIe RX TLP data payload (Units of bytes)::



    $# perf stat -a -e dwc_rootport_3018/Rx_PCIe_TLP_Data_Payload/

    $# perf stat -a -e dwc_rootport_13018/Rx_PCIe_TLP_Data_Payload/



The average RX/TX bandwidth can be calculated using the following formula:
@@ -88,7 +88,7 @@ Lane Event Usage 
Each lane has the same event set and to avoid generating a list of hundreds

of events, the user need to specify the lane ID explicitly, e.g.::



    $# perf stat -a -e dwc_rootport_3018/rx_memory_read,lane=4/

    $# perf stat -a -e dwc_rootport_13018/rx_memory_read,lane=4/



The driver does not support sampling, therefore "perf record" will not

work. Per-task (without "-a") perf sessions are not supported.