[PATCH v3 26/26] x86/resctrl: Update Documentation for package events

Tony Luck
2025-04-07T23:41:04Z

Each "mon_data" directory is now divided between L3 events and package
events.

The "info/PERF_PKG_MON" directory contains parameters for perf events.

Signed-off-by: Tony Luck <tony.luck@intel.com>
---
Documentation/filesystems/resctrl.rst | 38 ++++++++++++++++++++-------
1 file changed, 28 insertions(+), 10 deletions(-)

diff --git a/Documentation/filesystems/resctrl.rst b/Documentation/filesystems/resctrl.rst
index 6768fc1fad16..b89a188b0321 100644
--- a/Documentation/filesystems/resctrl.rst
+++ b/Documentation/filesystems/resctrl.rst
@@ -167,7 +167,7 @@ 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 RDT L3 monitoring is available there will be an "L3_MON" directory
with the following files:

"num_rmids":
@@ -261,6 +261,17 @@ with the following files:
bytes) at which a previously used LLC_occupancy
counter can be considered for re-use.

+If RDT PERF monitoring is available there will be an "L3_PERF_PKG" directory
+with the following files:
+
+"num_rmids":
+ The guaranteed number of hardware countes supporting RMIDs.
+ If more "CTRL_MON" + "MON" groups than this number are created,
+ the system may report that counters are "unavailable" when read.
+
+"mon_features":
+ Lists the perf monitoring events that are enabled on this system.
+
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
@@ -366,15 +377,22 @@ 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
- MON groups. Please see example section for more details on usage.
+ This contains a set of directories, one for each instance
+ of an L3 cache, or of a processor package. The L3 cache
+ directories are named "mon_L3_00", "mon_L3_01" etc. The
+ package directories "mon_PERF_PKG_00", "mon_PERF_PKG_01" etc.
+
+ Within each directory there is one file per event. In
+ the L3 directories: "llc_occupancy", "mbm_total_bytes",
+ and "mbm_local_bytes". In the PERF_PKG directories: "core_energy",
+ "activity", etc.
+
+ 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"
--
2.48.1