Merge pull request #48469 from jsturtevant/win-mem-cpu-feautre

Docs: Windows CPU and Memory Affinity

content/en/docs/reference/command-line-tools-reference/feature-gates/windows-cpu-and-memory-affinity.md

@@ -0,0 +1,17 @@
+---
+title: WindowsCPUAndMemoryAffinity
+content_type: feature_gate
+
+_build:
+  list: never
+  render: false
+
+stages:
+  - stage: alpha 
+    defaultValue: false
+    fromVersion: "1.32"
+---
+
+Add CPU and Memory Affinity support to Windows nodes with [CPUManager](/docs/tasks/administer-cluster/cpu-management-policies/#windows-support),
+[MemoryManager](/docs/tasks/administer-cluster/memory-manager/#windows-support)
+and topology manager.

content/en/docs/tasks/administer-cluster/cpu-management-policies.md

@@ -49,6 +49,14 @@ However, in workloads where CPU cache affinity and scheduling latency
 significantly affect workload performance, the kubelet allows alternative CPU
 management policies to determine some placement preferences on the node.
 
+## Windows Support
+
+{{< feature-state feature_gate_name="WindowsCPUAndMemoryAffinity" >}}
+
+CPU Manager support can be enabled on Windows by using the `WindowsCPUAndMemoryAffinity` feature gate
+and it requires support in the container runtime.
+Once the feature gate is enabled, follow the steps below to configure the [CPU manager policy](#configuration).
+
 ### Configuration
 
 The CPU Manager policy is set with the `--cpu-manager-policy` kubelet

content/en/docs/tasks/administer-cluster/memory-manager.md

@@ -46,7 +46,7 @@ Preceding v1.22, the `kubelet` must be started with the following flag:
 
 in order to enable the Memory Manager feature.
 
-## How Memory Manager Operates?
+## How does the Memory Manager Operate?
 
 The Memory Manager currently offers the guaranteed memory (and hugepages) allocation
 for Pods in Guaranteed QoS class.
@@ -57,7 +57,7 @@ prepare and deploy a `Guaranteed` pod as illustrated in the section
 
 The Memory Manager is a Hint Provider, and it provides topology hints for
 the Topology Manager which then aligns the requested resources according to these topology hints.
-It also enforces `cgroups` (i.e. `cpuset.mems`) for pods.
+On Linux, it also enforces `cgroups` (i.e. `cpuset.mems`) for pods.
 The complete flow diagram concerning pod admission and deployment process is illustrated in
 [Memory Manager KEP: Design Overview][4] and below:
 
@@ -91,6 +91,14 @@ The problem has been solved as elaborated in
 Also, reference [Memory Manager KEP: Simulation - how the Memory Manager works? (by examples)][1]
 illustrates how the management of groups occurs.
 
+### Windows Support
+
+{{< feature-state feature_gate_name="WindowsCPUAndMemoryAffinity" >}}
+
+Windows support can be enabled via the `WindowsCPUAndMemoryAffinity` feature gate
+and it requires support in the container runtime.
+Only the [BestEffort Policy](#policy-best-effort) is supported on Windows.
+
 ## Memory Manager configuration
 
 Other Managers should be first pre-configured. Next, the Memory Manager feature should be enabled
@@ -103,7 +111,8 @@ node stability (section [Reserved memory flag](#reserved-memory-flag)).
 Memory Manager supports two policies. You can select a policy via a `kubelet` flag `--memory-manager-policy`:
 
 * `None` (default)
-* `Static`
+* `Static` (Linux only)
+* `BestEffort` (Windows Only)
 
 #### None policy {#policy-none}
 
@@ -123,6 +132,24 @@ In the case of the `BestEffort` or `Burstable` pod, the `Static` Memory Manager
 the default topology hint as there is no request for the guaranteed memory,
 and does not reserve the memory in the internal [NodeMap][2] object.
 
+This policy is only supported on Linux.
+
+#### BestEffort policy {#policy-best-effort}
+
+{{< feature-state feature_gate_name="WindowsCPUAndMemoryAffinity" >}}
+
+This policy is only supported on Windows.
+
+On Windows, NUMA node assignment works differently than Linux.
+There is no mechanism to ensure that Memory access only comes from a specific NUMA node.
+Instead the Windows scheduler will select the most optimal NUMA node based on the CPU(s) assignments.
+It is possible that Windows might use other NUMA nodes if deemed optimal by the Windows scheduler. 
+
+The policy does track the amount of memory available and requested through the internal [NodeMap][2]. 
+The memory manager will make a best effort at ensuring that enough memory is available on
+a NUMA node before making the assignment.  
+This means that in most cases memory assignment should function as expected.
+
 ### Reserved memory flag
 
 The [Node Allocatable](/docs/tasks/administer-cluster/reserve-compute-resources/) mechanism

content/en/docs/tasks/administer-cluster/topology-manager.md

@@ -58,6 +58,13 @@ the pod can be accepted or rejected from the node based on the selected hint.
 The hint is then stored in the Topology Manager for use by the *Hint Providers* when making the
 resource allocation decisions.
 
+## Windows Support
+
+{{< feature-state feature_gate_name="WindowsCPUAndMemoryAffinity" >}}
+
+The Topology Manager support can be enabled on Windows by using the `WindowsCPUAndMemoryAffinity` feature gate and
+it requires support in the container runtime.
+
 ## Topology manager scopes and policies
 
 The Topology Manager currently: