Documentation/admin-guide/perf/starfive_starlink_pmu.rst

   1 ================================================
   2 StarFive StarLink Performance Monitor Unit (PMU)
   3 ================================================
   4
   5 StarFive StarLink Performance Monitor Unit (PMU) exists within the
   6 StarLink Coherent Network on Chip (CNoC) that connects multiple CPU
   7 clusters with an L3 memory system.
   8
   9 The uncore PMU supports overflow interrupt, up to 16 programmable 64bit
  10 event counters, and an independent 64bit cycle counter.
  11 The PMU can only be accessed via Memory Mapped I/O and are common to the
  12 cores connected to the same PMU.
  13
  14 Driver exposes supported PMU events in sysfs "events" directory under::
  15
  16   /sys/bus/event_source/devices/starfive_starlink_pmu/events/
  17
  18 Driver exposes cpu used to handle PMU events in sysfs "cpumask" directory
  19 under::
  20
  21   /sys/bus/event_source/devices/starfive_starlink_pmu/cpumask/
  22
  23 Driver describes the format of config (event ID) in sysfs "format" directory
  24 under::
  25
  26   /sys/bus/event_source/devices/starfive_starlink_pmu/format/
  27
  28 Example of perf usage::
  29
  30         $ perf list
  31
  32         starfive_starlink_pmu/cycles/                      [Kernel PMU event]
  33         starfive_starlink_pmu/read_hit/                    [Kernel PMU event]
  34         starfive_starlink_pmu/read_miss/                   [Kernel PMU event]
  35         starfive_starlink_pmu/read_request/                [Kernel PMU event]
  36         starfive_starlink_pmu/release_request/             [Kernel PMU event]
  37         starfive_starlink_pmu/write_hit/                   [Kernel PMU event]
  38         starfive_starlink_pmu/write_miss/                  [Kernel PMU event]
  39         starfive_starlink_pmu/write_request/               [Kernel PMU event]
  40         starfive_starlink_pmu/writeback/                   [Kernel PMU event]
  41
  42
  43         $ perf stat -a -e /starfive_starlink_pmu/cycles/ sleep 1
  44
  45 Sampling is not supported. As a result, "perf record" is not supported.
  46 Attaching to a task is not supported, only system-wide counting is supported.