@@ -0,0 +1,129 @@
+======================================
+HNS3 Performance Monitoring Unit (PMU)
+======================================
+
+HNS3(HiSilicon network system 3) Performance Monitoring Unit (PMU) is an
+End Point device to collect performance statistics of HiSilicon SoC NIC.
+On Hip09, each SICL(Super I/O cluster) has one PMU device.
+
+HNS3 PMU is supported to collect performance statistics of bandwidth,
+latency, packet rate and interrupt rate.
+
+Each HNS3 PMU supports up to 8 hardware events.
+
+HNS3 PMU driver
+===============
+
+The HNS3 PMU driver registers a perf PMU with the name of its device id.::
+
+  /sys/devices/hns3_pmu_<device_id>
+
+The device_id is read from hardware register, it contains information of
+chip_id(bit 31:2) and SICL_ID(bit 1:0). One chip may have one or more SICL.
+
+PMU driver provides description of available events, filter modes, format,
+identifier and cpumask in sysfs.
+
+The "events" directory describes the event code and subevent code of all
+supported events shown in perf list.
+
+The "filtermode" directory describes the supported filter modes of each
+event.
+
+The "format" directory describes all formats of the config (events) and
+config1 (filter options) fields of the perf_event_attr structure.
+
+The "identifier" file shows version of PMU hardware device.
+
+Example usage of checking event code and subevent code::
+
+  $# cat /sys/devices/hns3_pmu_0/events/bw_igu_ssu
+  config=0x0000
+
+The upper 8 bits of config is event code, lower 8 bits of config is
+subevent code.
+
+Example usage of checking supported filter mode::
+
+  $# cat /sys/devices/hns3_pmu_0/filtermode/bw_igu_ssu
+  filter mode supported: global/port/port-tc/
+
+Example usage of perf::
+
+  $# perf list
+  hns3_pmu_0/bw_igu_ssu/ [kernel PMU event]
+  ------------------------------------------
+
+  $# perf stat -a -e hns3_pmu_0/bw_igu_ssu,global=1/ -I 1000
+  or
+  $# perf stat -a -e hns3_pmu_0/event=0,subevent=0,global=1/ -I 1000
+
+The current driver does not support sampling. So "perf record" is unsupported.
+Also attach to a task is unsupported for HNS3 PMU.
+
+Filter modes
+--------------
+
+1. global mode
+PMU collect performance statistic of all functions of IO DIE. Set the
+"global" filter option to 1 will enable this mode.
+Example usage of perf::
+
+  $# perf stat -a -e hns3_pmu_0/event=0,subevent=0,global=1/ -I 1000
+
+2. port mode
+PMU collect performance statistic of one whole physical port. The port id
+is same as mac id. The "tc" filter option must be set to 0xF in this mode.
+Example usage of perf::
+
+  $# perf stat -a -e hns3_pmu_0/event=0,subevent=0,port=0,tc=0xF/ -I 1000
+
+3. port-tc mode
+PMU collect performance statistic of one tc of physical port. The port id
+is same as mac id. The "tc" filter option must be set to 0 ~ 7 in this
+mode.
+Example usage of perf::
+
+  $# perf stat -a -e hns3_pmu_0/event=0,subevent=0,port=0,tc=0/ -I 1000
+
+4. func mode
+PMU collect performance statistic of one PF/VF. The function id is BDF of
+PF/VF, its conversion formula::
+
+  func = (bus << 8) + (device << 3) + (function)
+
+for example:
+  BDF         func
+  35:00.0    0x3500
+  35:00.1    0x3501
+  35:01.0    0x3508
+
+In this mode, the "queue" filter option must be set to 0xFFFF.
+Example usage of perf::
+
+  $# perf stat -a -e hns3_pmu_0/event=0,subevent=0,bdf=0x3500,queue=0xFFFF/ -I 1000
+
+5. func-queue mode
+PMU collect performance statistic of one queue of PF/VF. The function id
+is BDF of PF/VF, its conversion formula::
+
+  func = (bus << 8) + (device << 3) + (function)
+
+In this mode, the "queue" filter option must be set to the exact queue id
+of function.
+Example usage of perf::
+
+  $# perf stat -a -e hns3_pmu_0/event=0,subevent=0,bdf=0x3500,queue=0/ -I 1000
+
+
+6. func-intr mode
+PMU collect performance statistic of one interrupt of PF/VF. The function
+id is BDF of PF/VF, its conversion formula::
+
+  func = (bus << 8) + (device << 3) + (function)
+
+In this mode, the "intr" filter option must be set to the exact interrupt
+id of function.
+Example usage of perf::
+
+  $# perf stat -a -e hns3_pmu_0/event=0,subevent=0,bdf=0x3500,intr=0/ -I 1000