config-linux: add intelRdt.enableMonitoring

config-linux.md

@@ -748,6 +748,7 @@ The following parameters can be specified for the container:
 * **`memBwSchema`** *(string, OPTIONAL)* - specifies the schema of memory bandwidth per L3 cache id.
     The value MUST start with `MB:` and MUST NOT contain newlines.
 * **`schemata`** *(array of strings, OPTIONAL)* - specifies the schemata to be written to the `schemata` file in resctrlfs. Each element represents one line in the `schemata` file. The value MUST NOT contain newlines.
+* **`enableMonitoring`** *(boolean, OPTIONAL)* - enables resctrl monitoring for the container.
 
 The following rules on parameters MUST be applied:
 
@@ -769,13 +770,20 @@ The following rules on parameters MUST be applied:
 
 * If `closID` is set, and none of `l3CacheSchema`, `memBwSchema` or `schemata` are set, runtime MUST check if corresponding pre-configured directory `closID` is present in mounted `resctrl`. If such pre-configured directory `closID` exists, runtime MUST assign container to this `closID` and [generate an error](runtime.md#errors) if directory does not exist.
 
-* **`enableCMT`** *(boolean, OPTIONAL)* - specifies if Intel RDT CMT should be enabled:
-    * CMT (Cache Monitoring Technology) supports monitoring of the last-level cache (LLC) occupancy
-      for the container.
-
-* **`enableMBM`** *(boolean, OPTIONAL)* - specifies if Intel RDT MBM should be enabled:
-    * MBM (Memory Bandwidth Monitoring) supports monitoring of total and local memory bandwidth
-      for the container.
+* If `enableMonitoring` is set, the runtime MUST create a dedicated MON group
+  for the container. The runtime MUST use the container ID from
+  [`start`](runtime.md#start) as the name of the MON group, i.e. create
+  `mon_groups/<container-id>/` subdirectory under the top-level CTRL_MON group
+  (named after `closID` or `<container-id>`, see above). The runtime MUST
+  delete the MON group after the container is deleted. If creation of the MON
+  group fails (e.g. the maximum number of MON groups is reached) the runtime MUST
+  return an error.
+
+> **NOTE:** The `enableCMT` and `enableMBM` parameters, available in runtime-spec versions v1.1.0 through v1.2.1, were
+> replaced with a unified `enableMonitoring` parameter in v1.3.0. Their semantics were loosely defined and there were
+> no known implementations. More critically, these parameters were problematic as hardware does not support selective
+> enabling of individual monitoring features. This scheme also made it unnecessarily complex to add support for new
+> monitoring features, without providing any recognized benefits.
 
 ### Example
 

schema/config-linux.json

@@ -278,10 +278,7 @@
                         "type": "string",
                         "pattern": "^MB:[^\\n]*$"
                     },
-                    "enableCMT": {
-                        "type": "boolean"
-                    },
-                    "enableMBM": {
+                    "enableMonitoring": {
                         "type": "boolean"
                     }
                 }

specs-go/config.go

@@ -855,13 +855,9 @@ type LinuxIntelRdt struct {
 	// NOTE: Should not be specified if Schemata is non-empty.
 	MemBwSchema string `json:"memBwSchema,omitempty"`
 
-	// EnableCMT is the flag to indicate if the Intel RDT CMT is enabled. CMT (Cache Monitoring Technology) supports monitoring of
-	// the last-level cache (LLC) occupancy for the container.
-	EnableCMT bool `json:"enableCMT,omitempty"`
-
-	// EnableMBM is the flag to indicate if the Intel RDT MBM is enabled. MBM (Memory Bandwidth Monitoring) supports monitoring of
-	// total and local memory bandwidth for the container.
-	EnableMBM bool `json:"enableMBM,omitempty"`
+	// EnableMonitoring enables resctrl monitoring for the container. This will
+	// create a dedicated resctrl monitoring group for the container.
+	EnableMonitoring bool `json:"enableMonitoring,omitempty"`
 }
 
 // ZOS contains platform-specific configuration for z/OS based containers.