[PATCH 6/7] x86/resctrl: Update documentation with Sub-NUMA cluster changes

From: Tony Luck
Date: Thu Jan 26 2023 - 13:42:54 EST


With Sub-NUMA Cluster mode enabled the scope of monitoring resources is
per-NODE instead of per-L3 cache. Suffices of directories with "L3" in
their name refer to Sun-NUMA nodes instead of L3 cache ids.

Signed-off-by: Tony Luck <tony.luck@xxxxxxxxx>
---
Documentation/x86/resctrl.rst | 15 ++++++++++++---
1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/Documentation/x86/resctrl.rst b/Documentation/x86/resctrl.rst
index 71a531061e4e..9043a2d2f2d3 100644
--- a/Documentation/x86/resctrl.rst
+++ b/Documentation/x86/resctrl.rst
@@ -167,6 +167,11 @@ with the following files:
bytes) at which a previously used LLC_occupancy
counter can be considered for re-use.

+"snc_ways":
+ A value of "1" marks that SNC mode is disabled.
+ Values of "2" or "4" indicate how many NUMA
+ nodes share an L3 cache.
+
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
@@ -254,9 +259,13 @@ 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
+ This contains a set of files organized by L3 domain or by NUMA
+ node (depending on whether SNC mode is disabled or enabled
+ respectively) and by RDT event. E.g. on a system with SNC
+ mode disabled with two L3 domains there will be subdirectories
+ "mon_L3_00" and "mon_L3_01" the numerical suffix refers to the
+ L3 cache id. With SNC enabled the directory names are the same,
+ but the numerical suffix refers to the node id. 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
--
2.39.1