[PATCH v3 0/3] perf pmu: Add tool-provided NVMe PMU

[Ian Rogers <irogers@google.com>]

This series adds a tool-provided PMU for NVMe controllers using libnvme,
following the same pattern as the existing tool, hwmon, and drm PMUs.
Each discovered controller is exposed as an 'nvme_<ctrl>' PMU (with
alias '<ctrl>', e.g. 'nvme_nvme0' and 'nvme0') providing events from
standard NVMe log pages: SMART / Health Information, Endurance Group
Information, Flexible Data Placement (FDP) Statistics, Error
Information, and Zoned Namespaces (ZNS) Changed Zones.

Motivation / Use Cases
======================
While standalone tools such as nvme-cli can dump individual log pages on
demand, exposing NVMe controller log metrics as a perf tool PMU allows
storage metrics (host/media bytes written, write amplification and FDP
efficiency, read/write command counts, controller busy time, error
counters, and device temperature) to be sampled on a unified timeline
alongside CPU hardware counters, kernel/block events, uncore counters,
and hwmon/drm sensors in 'perf stat' (including interval mode '-I', CSV
'-x', JSON '-j', and perf metric formulas), without custom wrapper
scripts. Discovery and log-page probing are gated behind
PERF_TOOL_PMU_TYPE_NVME_MASK so commands that do not request NVMe events
incur zero overhead.

Example Output
==============
Listing available NVMe events (unsupported log pages on the controller
are marked deprecated and hidden from default 'perf list'):

 $ perf list nvme

 List of pre-defined events (to be used in -e or -M):

 nvme:
   smart_crit_comp_time
        [Critical composite temperature time. Unit: nvme_nvme0]
   smart_ctrl_busy_time
        [Controller busy time. Unit: nvme_nvme0]
   smart_data_units_read
        [Data units read (in 1000s of 512-byte units). Unit: nvme_nvme0]
   smart_data_units_written
        [Data units written (in 1000s of 512-byte units). Unit: nvme_nvme0]
   smart_host_read_commands
        [Host read commands. Unit: nvme_nvme0]
   smart_host_write_commands
        [Host write commands. Unit: nvme_nvme0]
   smart_media_errors
        [Media errors. Unit: nvme_nvme0]
   smart_num_err_log_entries
        [Number of error log entries. Unit: nvme_nvme0]
   smart_power_cycles
        [Power cycles. Unit: nvme_nvme0]
   smart_power_on_hours
        [Power on hours. Unit: nvme_nvme0]
   smart_temperature
        [Temperature. Unit: nvme_nvme0]
   smart_unsafe_shutdowns
        [Unsafe shutdowns. Unit: nvme_nvme0]
   smart_warning_temp_time
        [Warning temperature time. Unit: nvme_nvme0]

 $ perf list --details nvme_nvme0/smart_temperature/

 List of pre-defined events (to be used in -e or -M):

 nvme:
   smart_temperature
        [Temperature. Unit: nvme_nvme0]
     nvme_nvme0/config=0x20001/

Interval 'perf stat' output (captured with mocked libnvme SMART log
responses on /dev/nvme0):

 $ perf stat -a -I 500 -e smart_temperature,smart_data_units_read,\
   smart_data_units_written,smart_host_read_commands,\
   smart_host_write_commands -- sleep 1
 #           time             counts unit events
      0.500432960                311 K    smart_temperature
      0.500432960         36,864,000 B    smart_data_units_read
      0.500432960         12,288,000 B    smart_data_units_written
      0.500432960                900      smart_host_read_commands
      0.500432960                270      smart_host_write_commands
      1.001068028                311 K    smart_temperature
      1.001068028         36,864,000 B    smart_data_units_read
      1.001068028         12,288,000 B    smart_data_units_written
      1.001068028                900      smart_host_read_commands
      1.001068028                270      smart_host_write_commands

Changes in v3:
- Remove accidental internal tracking tags from commit messages
  (Christoph Hellwig).
- Document use cases and include actual 'perf list' and 'perf stat'
  example output in the cover letter and Patch 2 commit message, and
  document NVMe events in Documentation/perf-list.txt (Christoph
  Hellwig, Namhyung Kim).
- Rely on $(FEATURE_CHECK_LDFLAGS-libnvme) from pkg-config when building
  test-libnvme.bin instead of hardcoding -lnvme, and add test-libnvme.bin
  to FILES in tools/build/feature/Makefile.
- Report smart_temperature in native Kelvins ('1K') to avoid unsigned
  uint64_t underflow on sub-zero Celsius or 0 K readings; metrics can
  convert Kelvin to Celsius.
- Support advertised 'config=0x...' raw encodings, 'event=<name>', and
  standard event qualifiers ('name=', 'metric-id=', 'cpu='), and guard
  NULL term->config when formatting parse errors.
- Check xyarray__new() allocation failure (-ENOMEM), propagate initial
  log read errors (-EPERM / -EOPNOTSUPP) in evsel__nvme_pmu_open(), and
  bound incremental open error unwind by start_cpu_map_idx.
- Use an aligned union of NVMe log structures in nvme_pmu__read_val(),
  use valid Endurance Group ID 1 (0 is reserved in NVMe) for Endurance
  Group and FDP logs, fix Endurance Group data/media unit scaling to
  billions of bytes ('1000000000B') per NVMe Base Spec, wire up
  perf_pmus__find_by_type() for NVMe PMU types, and propagate
  nvme_pmu__check_alias() errors in perf_pmu__check_alias().
- Expand unit tests to cover alias PMUs, 'event=', 'config=0x...',
  'name=' qualifiers, unit/scale checks, and invalid term rejection.

Changes in v2:
https://lore.kernel.org/linux-perf-users/20260609165726.786694-1-irogers@google.com/
- Include test-libnvme.c in test-all.c and add libnvme to
  FEATURE_PKG_CONFIG.
- Use get_unaligned_le*() helpers when reading NVMe log fields.
- Move baseline initial_values xyarray from tool-owned evsel->priv into
  struct evsel's tool union (evsel->nvme.initial_values) and free it in
  evsel__exit().

v1:
https://lore.kernel.org/linux-perf-users/20260609070348.541964-1-irogers@google.com/

Ian Rogers (3):
  perf build: Add libnvme feature detection
  perf pmu: Implement tool-provided NVMe PMU
  perf tests: Add NVMe PMU event parsing test

 tools/build/Makefile.feature           |   5 +-
 tools/build/feature/Makefile           |   4 +
 tools/build/feature/test-all.c         |   5 +
 tools/build/feature/test-libnvme.c     |  11 +
 tools/perf/Documentation/perf-list.txt |  10 +-
 tools/perf/Makefile.config             |  12 +
 tools/perf/tests/Build                 |   1 +
 tools/perf/tests/builtin-test.c        |   1 +
 tools/perf/tests/nvme_pmu.c            | 303 +++++++++++
 tools/perf/tests/tests.h               |   1 +
 tools/perf/util/Build                  |   1 +
 tools/perf/util/evsel.c                |  13 +-
 tools/perf/util/evsel.h                |   4 +
 tools/perf/util/nvme_pmu.c             | 691 +++++++++++++++++++++++++
 tools/perf/util/nvme_pmu.h             | 144 ++++++
 tools/perf/util/pmu.c                  |  17 +
 tools/perf/util/pmu.h                  |   8 +-
 tools/perf/util/pmus.c                 |  24 +
 tools/perf/util/pmus.h                 |   1 +
 19 files changed, 1250 insertions(+), 6 deletions(-)
 create mode 100644 tools/build/feature/test-libnvme.c
 create mode 100644 tools/perf/tests/nvme_pmu.c
 create mode 100644 tools/perf/util/nvme_pmu.c
 create mode 100644 tools/perf/util/nvme_pmu.h

-- 
2.56.1.703.gf848ed807c-goog