x86,fs/resctrl: Update documentation for telemetry events

Update resctrl filesystem documentation with the details about the resctrl
files that support telemetry events.

  [ bp: Drop the debugfs hunk of the documentation until a better debugging
    solution is found. ]

Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com

diff --git a/Documentation/filesystems/resctrl.rst b/Documentation/filesystems/resctrl.rst
index 8c8ce678148a524b1a30e4c5f51b5df342a5d149..45dde877412881e5aa3bc91ac3c3e59451f6944c 100644 (file)
--- a/Documentation/filesystems/resctrl.rst
+++ b/Documentation/filesystems/resctrl.rst
@@ -252,13 +252,12 @@ with respect to allocation:
                        bandwidth percentages are directly applied to
                        the threads running on the core
 
-If RDT monitoring is available there will be an "L3_MON" directory
+If L3 monitoring is available there will be an "L3_MON" directory
 with the following files:
 
 "num_rmids":
-               The number of RMIDs available. This is the
-               upper bound for how many "CTRL_MON" + "MON"
-               groups can be created.
+               The number of RMIDs supported by hardware for
+               L3 monitoring events.
 
 "mon_features":
                Lists the monitoring events if
@@ -484,6 +483,24 @@ with the following files:
                bytes) at which a previously used LLC_occupancy
                counter can be considered for re-use.
 
+If telemetry monitoring is available there will be a "PERF_PKG_MON" directory
+with the following files:
+
+"num_rmids":
+               The number of RMIDs for telemetry monitoring events.
+
+               On Intel resctrl will not enable telemetry events if the number of
+               RMIDs that can be tracked concurrently is lower than the total number
+               of RMIDs supported. Telemetry events can be force-enabled with the
+               "rdt=" kernel parameter, but this may reduce the number of
+               monitoring groups that can be created.
+
+"mon_features":
+               Lists the telemetry monitoring events that are enabled on this system.
+
+The upper bound for how many "CTRL_MON" + "MON" can be created
+is the smaller of the L3_MON and PERF_PKG_MON "num_rmids" values.
+
 Finally, in the top level of the "info" directory there is a file
 named "last_cmd_status". This is reset with every "command" issued
 via the file system (making new directories or writing to any of the
@@ -589,15 +606,40 @@ When control is enabled all CTRL_MON groups will also contain:
 When monitoring is enabled all MON groups will also contain:
 
 "mon_data":
-       This contains a set of files organized by L3 domain and by
-       RDT event. E.g. on a system with two L3 domains there will
-       be subdirectories "mon_L3_00" and "mon_L3_01".  Each of these
-       directories have one file per event (e.g. "llc_occupancy",
-       "mbm_total_bytes", and "mbm_local_bytes"). In a MON group these
-       files provide a read out of the current value of the event for
-       all tasks in the group. In CTRL_MON groups these files provide
-       the sum for all tasks in the CTRL_MON group and all tasks in
+       This contains directories for each monitor domain.
+
+       If L3 monitoring is enabled, there will be a "mon_L3_XX" directory for
+       each instance of an L3 cache. Each directory contains files for the enabled
+       L3 events (e.g. "llc_occupancy", "mbm_total_bytes", and "mbm_local_bytes").
+
+       If telemetry monitoring is enabled, there will be a "mon_PERF_PKG_YY"
+       directory for each physical processor package. Each directory contains
+       files for the enabled telemetry events (e.g. "core_energy". "activity",
+       "uops_retired", etc.)
+
+       The info/`*`/mon_features files provide the full list of enabled
+       event/file names.
+
+       "core energy" reports a floating point number for the energy (in Joules)
+       consumed by cores (registers, arithmetic units, TLB and L1/L2 caches)
+       during execution of instructions summed across all logical CPUs on a
+       package for the current monitoring group.
+
+       "activity" also reports a floating point value (in Farads).  This provides
+       an estimate of work done independent of the frequency that the CPUs used
+       for execution.
+
+       Note that "core energy" and "activity" only measure energy/activity in the
+       "core" of the CPU (arithmetic units, TLB, L1 and L2 caches, etc.). They
+       do not include L3 cache, memory, I/O devices etc.
+
+       All other events report decimal integer values.
+
+       In a MON group these files provide a read out of the current value of
+       the event for all tasks in the group. In CTRL_MON groups these files
+       provide the sum for all tasks in the CTRL_MON group and all tasks in
        MON groups. Please see example section for more details on usage.
+
        On systems with Sub-NUMA Cluster (SNC) enabled there are extra
        directories for each node (located within the "mon_L3_XX" directory
        for the L3 cache they occupy). These are named "mon_sub_L3_YY"