Thread (5 messages) 5 messages, 2 authors, 2021-03-25

Re: [RFC PATCH 1/2] {topost} drivers/perf: hisi: Add description for HNS3 PMU driver

From: John Garry <hidden>
Date: 2021-03-25 15:17:40

On 22/03/2021 01:49, Guangbin Huang wrote:

please remove {topost} next time
HNS3 PMU End Point device is supported on HiSilicon HIP09 platform, so
add document hns3-pmu.rst to provide guidance on how to use it.
sorry, I didn't do much review of this before sending out...
quoted hunk ↗ jump to hunk
Signed-off-by: Guangbin Huang <redacted>
---
  Documentation/admin-guide/perf/hns3-pmu.rst | 125 ++++++++++++++++++++++++++++
  1 file changed, 125 insertions(+)
  create mode 100644 Documentation/admin-guide/perf/hns3-pmu.rst
diff --git a/Documentation/admin-guide/perf/hns3-pmu.rst b/Documentation/admin-guide/perf/hns3-pmu.rst
new file mode 100644
index 0000000..3597a8e
--- /dev/null
+++ b/Documentation/admin-guide/perf/hns3-pmu.rst
@@ -0,0 +1,125 @@
+======================================
+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 has one PMU device.
Even though the hisi-pmu doc now mentions what is SICL, it is also 
better mention here what it is.
+
+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>
any reason for which sicl is not used in the same?

How is a anyone supposed to know which device hns3_pmu_0 - for example - 
is ?
+
+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.
+
+The "cpumask" file shows which CPU is PMU driver running on.
isn't that really the CPUs associated with that PMU?
+
+Example usage of checking event code and subevent code::
+
+  $# cat /sys/devices/hns3_pmu_0/events/bw_igu_ssu
+  event=0x0, subevent=0x0
as below
+
+Example usage of checking supported filter mode::
+
+  $# cat /sys/devices/hns3_pmu_0/filtermode/bw_igu_ssu
+  filter mode supported: global/port/port-tc/
A sysfs file should just hold a single value is a basic rule
+
+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
any reason why we can't have each nibble holding a digit of BDF?  0x3508 
look strange
+
+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,func=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,func=0x3500,queue=0/ -I 1000
+
To me it's odd that the difference between func mode and func-queue mode 
is just setting the queue=0xffff or queue=0 - seems to be just the same 
mode with a different queue option
+
+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,func=0x3500,intr=0/ -I 1000

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