Generate TopologyHints from the CPUManager

pkg/kubelet/cm/cpumanager/BUILD

@@ -20,6 +20,7 @@ go_library(
         "//pkg/kubelet/cm/cpumanager/topology:go_default_library",
         "//pkg/kubelet/cm/cpuset:go_default_library",
         "//pkg/kubelet/cm/topologymanager:go_default_library",
+        "//pkg/kubelet/cm/topologymanager/socketmask:go_default_library",
         "//pkg/kubelet/container:go_default_library",
         "//pkg/kubelet/status:go_default_library",
         "//staging/src/k8s.io/api/core/v1:go_default_library",
@@ -46,6 +47,7 @@ go_test(
         "//pkg/kubelet/cm/cpumanager/topology:go_default_library",
         "//pkg/kubelet/cm/cpuset:go_default_library",
         "//pkg/kubelet/cm/topologymanager:go_default_library",
+        "//pkg/kubelet/cm/topologymanager/socketmask:go_default_library",
         "//staging/src/k8s.io/api/core/v1:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/api/resource:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/apis/meta/v1:go_default_library",

pkg/kubelet/cm/cpumanager/policy_static.go

@@ -190,7 +190,7 @@ func (p *staticPolicy) AddContainer(s state.State, pod *v1.Pod, container *v1.Co
 		}
 	}()
 
-	if numCPUs := guaranteedCPUs(pod, container); numCPUs != 0 {
+	if numCPUs := p.guaranteedCPUs(pod, container); numCPUs != 0 {
 		klog.Infof("[cpumanager] static policy: AddContainer (pod: %s, container: %s, container id: %s)", pod.Name, container.Name, containerID)
 		// container belongs in an exclusively allocated pool
 
@@ -257,7 +257,7 @@ func (p *staticPolicy) allocateCPUs(s state.State, numCPUs int) (cpuset.CPUSet,
 	return result, nil
 }
 
-func guaranteedCPUs(pod *v1.Pod, container *v1.Container) int {
+func (p *staticPolicy) guaranteedCPUs(pod *v1.Pod, container *v1.Container) int {
 	if v1qos.GetPodQOS(pod) != v1.PodQOSGuaranteed {
 		return 0
 	}

pkg/kubelet/cm/cpumanager/topology_hints.go

@@ -21,26 +21,107 @@ import (
 	"k8s.io/klog"
 
 	"k8s.io/kubernetes/pkg/kubelet/cm/cpumanager/topology"
+	"k8s.io/kubernetes/pkg/kubelet/cm/cpuset"
 	"k8s.io/kubernetes/pkg/kubelet/cm/topologymanager"
+	"k8s.io/kubernetes/pkg/kubelet/cm/topologymanager/socketmask"
 )
 
 func (m *manager) GetTopologyHints(pod v1.Pod, container v1.Container) []topologymanager.TopologyHint {
-	var cpuHints []topologymanager.TopologyHint
+	// The 'none' policy does not generate topology hints.
-	if requestedObj, ok := container.Resources.Requests[v1.ResourceCPU]; ok {
+	if m.policy.Name() == string(PolicyNone) {
-		// Get a count of how many CPUs have been requested
-		requested := int(requestedObj.Value())
-		klog.Infof("[cpumanager] Guaranteed CPUs detected: %v", requested)
-
-		// Discover topology in order to establish the number
-		// of available CPUs per socket.
-		_, err := topology.Discover(m.machineInfo)
-		if err != nil {
-			klog.Infof("[cpu manager] error discovering topology")
 		return nil
 	}
 
-		// TODO: Fill in cpuHints with proper TopologyHints
+	// For all other policies, if there are no CPU resources requested for this
+	// container, we do not generate any topology hints.
+	if _, ok := container.Resources.Requests[v1.ResourceCPU]; !ok {
+		return nil
 	}
-	klog.Infof("[cpumanager] Topology Hints for pod: %v", cpuHints)
+
+	// Otherwise, attempt to generate TopologyHints for the CPUManager.
+	// For now, this implementation assumes the 'static' CPUManager policy.
+	// TODO: Generalize this so that its applicable to future CPUManager polices.
+
+	// Get a count of how many guaranteed CPUs have been requested.
+	requested := m.policy.(*staticPolicy).guaranteedCPUs(&pod, &container)
+
+	// If there are no guaranteed CPUs being requested, we do not generate
+	// any topology hints. This can happen, for example, because init
+	// containers don't have to have guaranteed CPUs in order for the pod
+	// to still be in the Guaranteed QOS tier.
+	if requested == 0 {
+		return nil
+	}
+
+	// Get a list of available CPUs.
+	available := m.policy.(*staticPolicy).assignableCPUs(m.state)
+
+	// Generate hints.
+	cpuHints := m.generateCPUTopologyHints(available, requested)
+	klog.Infof("[cpumanager] TopologyHints generated for pod '%v', container '%v': %v", pod.Name, container.Name, cpuHints)
+
 	return cpuHints
 }
+
+// generateCPUtopologyHints generates a set of TopologyHints given the set of
+// available CPUs and the number of CPUs being requested.
+//
+// It follows the convention of marking all hints that have the same number of
+// bits set as the narrowest matching SocketAffinity with 'Preferred: true', and
+// marking all others with 'Preferred: false'.
+func (m *manager) generateCPUTopologyHints(availableCPUs cpuset.CPUSet, request int) []topologymanager.TopologyHint {
+	// Discover topology in order to establish the number
+	// of available CPUs per socket.
+	topo, err := topology.Discover(m.machineInfo)
+	if err != nil {
+		klog.Warningf("[cpu manager] Error discovering topology for TopologyHint generation")
+		return nil
+	}
+
+	// Initialize minAffinity to a full affinity mask.
+	minAffinity, _ := socketmask.NewSocketMask()
+	minAffinity.Fill()
+
+	// Iterate through all combinations of socketMasks and build hints from them.
+	hints := []topologymanager.TopologyHint{}
+	socketmask.IterateSocketMasks(topo.CPUDetails.Sockets().ToSlice(), func(mask socketmask.SocketMask) {
+		// Check to see if we have enough CPUs available on the current
+		// SocketMask to satisfy the CPU request.
+		numMatching := 0
+		for _, c := range availableCPUs.ToSlice() {
+			if mask.IsSet(topo.CPUDetails[c].SocketID) {
+				numMatching++
+			}
+		}
+
+		// If we don't, then move onto the next combination.
+		if numMatching < request {
+			return
+		}
+
+		// Otherwise, create a new hint from the SocketMask and add it to the
+		// list of hints.  We set all hint preferences to 'false' on the first
+		// pass through.
+		hints = append(hints, topologymanager.TopologyHint{
+			SocketAffinity: mask,
+			Preferred:      false,
+		})
+
+		// Update minAffinity if relevant
+		if mask.IsNarrowerThan(minAffinity) {
+			minAffinity = mask
+		}
+	})
+
+	// Loop back through all hints and update the 'Preferred' field based on
+	// counting the number of bits sets in the affinity mask and comparing it
+	// to the minAffinity. Only those with an equal number of bits set will be
+	// considered preferred.
+	for i := range hints {
+		if hints[i].SocketAffinity.Count() == minAffinity.Count() {
+			hints[i].Preferred = true
+		}
+	}
+
+	return hints
+}