balloons: add support for picking efficient/performance cores

This commit introduces a new field in the balloons configuration CR,
enabling users to specify their efficient/performance core preferences
for their workloads. When a user explicitly requests efficient or
performance cores, the policy will attempt to allocate according
to the user preferences. If the request cannot be satisfied, the
policy will fall back to other available cores  on the host.

If a user adds `preferIsolCpus` in addition to specifying coreTypes,
the policy will prioritize allocating isolated CPUs cores over the
preferred efficient/performance cores, in case these sets are different.

Signed-off-by: Feruzjon Muyassarov <[email protected]>

cmd/plugins/balloons/policy/balloons-policy.go

@@ -39,7 +39,6 @@ const (
 	PolicyName = "balloons"
 	// PolicyDescription is a short description of this policy.
 	PolicyDescription = "Flexible pools with per-pool CPU parameters"
-
 	// balloonKey is a pod annotation key, the value is a pod balloon name.
 	balloonKey = "balloon." + PolicyName + "." + kubernetes.ResmgrKeyNamespace
 	// hideHyperthreadsKey is a pod annotation key for pod/container-specific hyperthread allowance.
@@ -56,6 +55,12 @@ const (
 	// virtDevIsolatedCpus is the name of a virtual device close to
 	// host isolated CPUs.
 	virtDevIsolatedCpus = "isolated CPUs"
+	// virtDevECores is the name of a virtual device close to
+	// power efficient cores.
+	virtDevECores = "efficient cores"
+	// virtDevPCores is the name of a virtual device close to
+	// high performance cores.
+	virtDevPCores = "performance cores"
 )
 
 // balloons contains configuration and runtime attributes of the balloons policy
@@ -562,6 +567,8 @@ func (p *balloons) newBalloon(blnDef *BalloonDef, confCpus bool) (*Balloon, erro
 		virtDevCpusets: map[string][]cpuset.CPUSet{
 			virtDevReservedCpus: {p.reserved},
 			virtDevIsolatedCpus: {p.options.System.Isolated()},
+			virtDevECores:       {p.cpuAllocator.GetCPUPriorities()[cpuallocator.PriorityLow]},
+			virtDevPCores:       {p.cpuAllocator.GetCPUPriorities()[cpuallocator.PriorityHigh]},
 		},
 	}
 	if blnDef.AllocatorTopologyBalancing != nil {
@@ -1202,6 +1209,12 @@ func (p *balloons) fillCloseToDevices(blnDefs []*BalloonDef) {
 		if blnDef.PreferIsolCpus {
 			blnDef.PreferCloseToDevices = append(blnDef.PreferCloseToDevices, virtDevIsolatedCpus)
 		}
+		if blnDef.PreferCoreType == "performance" {
+			blnDef.PreferCloseToDevices = append(blnDef.PreferCloseToDevices, virtDevPCores)
+		}
+		if blnDef.PreferCoreType == "efficient" {
+			blnDef.PreferCloseToDevices = append(blnDef.PreferCloseToDevices, virtDevECores)
+		}
 	}
 }
 

config/crd/bases/config.nri_balloonspolicies.yaml

@@ -195,6 +195,14 @@ spec:
                       items:
                         type: string
                       type: array
+                    preferCoreType:
+                      description: |-
+                        preferCoreType: prefer performance or efficient (P/E) CPU cores on
+                        hybrid architectures.
+                      enum:
+                      - efficient
+                      - performance
+                      type: string
                     preferIsolCpus:
                       default: false
                       description: 'preferIsolCpus: prefer kernel isolated cpus'

deployment/helm/balloons/crds/config.nri_balloonspolicies.yaml

@@ -195,6 +195,14 @@ spec:
                       items:
                         type: string
                       type: array
+                    preferCoreType:
+                      description: |-
+                        preferCoreType: prefer performance or efficient (P/E) CPU cores on
+                        hybrid architectures.
+                      enum:
+                      - efficient
+                      - performance
+                      type: string
                     preferIsolCpus:
                       default: false
                       description: 'preferIsolCpus: prefer kernel isolated cpus'

pkg/apis/config/v1alpha1/resmgr/policy/balloons/config.go

@@ -219,6 +219,11 @@ type BalloonDef struct {
 	// preferIsolCpus: prefer kernel isolated cpus
 	// +kubebuilder:default:=false
 	PreferIsolCpus bool `json:"preferIsolCpus,omitempty"`
+	// preferCoreType: prefer performance or efficient (P/E) CPU cores on
+	// hybrid architectures.
+	// +optional
+	// +kubebuilder:validation:Enum:=efficient;performance
+	PreferCoreType string `json:"preferCoreType,omitempty"`
 }
 
 // String stringifies a BalloonDef