What:          /sys/class/intel_pmt/features-<PCI BDF>/
Date:          2025-04-24
KernelVersion: 6.16
Contact:       david.e.box@linux.intel.com
Description:
               The `features-<PCI BDF>/` directory represents the "features"
               capability exposed by Intel PMT (Platform Monitoring Technology)
               for the given PCI device.

               Each directory corresponds to a PMT feature and contains
               attributes describing the available telemetry, monitoring, or
               control functionalities.

Directory Structure:

  /sys/class/intel_pmt/features-<PCI BDF>/
  ├── accelerator_telemetry/		# Per-accelerator telemetry data
  ├── crash_log/			# Contains system crash telemetry logs
  ├── per_core_environment_telemetry/	# Environmental telemetry per core
  ├── per_core_performance_telemetry/	# Performance telemetry per core
  ├── per_rmid_energy_telemetry/	# Energy telemetry for RMIDs
  ├── per_rmid_perf_telemetry/		# Performance telemetry for RMIDs
  ├── tpmi_control/			# TPMI-related controls and telemetry
  ├── tracing/				# PMT tracing features
  └── uncore_telemetry/			# Uncore telemetry data

Common Files (Present in all feature directories):

  caps
    - Read-only
    - Lists available capabilities for this feature.

  guids
    - Read-only
    - Lists GUIDs associated with this feature.

Additional Attributes (Conditional Presence):

  max_command_size
    - Read-only
    - Present if the feature supports out-of-band MCTP access.
    - Maximum supported MCTP command size for out-of-band PMT access (bytes).

  max_stream_size
    - Read-only
    - Present if the feature supports out-of-band MCTP access.
    - Maximum supported MCTP stream size (bytes).

  min_watcher_period_ms
    - Read-only
    - Present if the feature supports the watcher API.
      The watcher API provides a writable control interface that allows user
      configuration of monitoring behavior, such as setting the sampling or
      reporting interval.
    - Minimum supported time period for the watcher interface (milliseconds).

  num_rmids
    - Read-only
    - Present if the feature supports RMID (Resource Monitoring ID) telemetry.
      RMIDs are identifiers used by hardware to track and report resource usage,
      such as memory bandwidth or energy consumption, on a per-logical-entity
      basis (e.g., per core, thread, or process group).
    - Maximum number of RMIDs tracked simultaneously.

Example:
For a device with PCI BDF `0000:00:03.1`, the directory tree could look like:

  /sys/class/intel_pmt/features-0000:00:03.1/
  ├── accelerator_telemetry/
  │   ├── caps
  │   ├── guids
  │   ├── max_command_size
  │   ├── max_stream_size
  │   ├── min_watcher_period_ms
  ├── crash_log/
  │   ├── caps
  │   ├── guids
  │   ├── max_command_size
  │   ├── max_stream_size
  ├── per_core_environment_telemetry/
  │   ├── caps
  │   ├── guids
  │   ├── max_command_size
  │   ├── max_stream_size
  │   ├── min_watcher_period_ms
  ├── per_rmid_energy_telemetry/
  │   ├── caps
  │   ├── guids
  │   ├── max_command_size
  │   ├── max_stream_size
  │   ├── min_watcher_period_ms
  │   ├── num_rmids
  ├── tpmi_control/
  │   ├── caps
  │   ├── guids
  ├── tracing/
  │   ├── caps
  │   ├── guids
  ├── uncore_telemetry/
  │   ├── caps
  │   ├── guids
  │   ├── max_command_size
  │   ├── max_stream_size
  │   ├── min_watcher_period_ms

Notes:
  - Some attributes are only present if the corresponding feature supports
    the capability (e.g., `max_command_size` for MCTP-capable features).
  - Features supporting RMIDs include `num_rmids`.
  - Features supporting the watcher API include `min_watcher_period_ms`.
  - The `caps` file provides additional information about the functionality
    of the feature.

Example 'caps' content for the 'tracing' feature:

  /sys/class/intel_pmt/features-0000:00:03.1/
  ├── tracing/
  │   ├── caps

	telemetry                                Available: No
	watcher                                  Available: Yes
	crashlog                                 Available: No
	streaming                                Available: No
	threashold                               Available: No
	window                                   Available: No
	config                                   Available: Yes
	tracing                                  Available: No
	inband                                   Available: Yes
	oob                                      Available: Yes
	secure_chan                              Available: No
	pmt_sp                                   Available: Yes
	pmt_sp_policy                            Available: Yes
	mailbox                                  Available: Yes
	bios_lock                                Available: Yes