add docs for how to set qp resources

docs/serving/services/configure-requests-limits-services.md

@@ -23,6 +23,48 @@ spec:
               cpu: 1
 ```
 
-## Additional resources
+## Configure Queue Proxy resources
+
+In order to set the Queue Proxy resource requests and limits you can either
+set them globally in the [deployment config map](../configuration/deployment.md) or you can set them at the service level using the corresponding annotations targeting cpu, memory and ephemeral-storage resource types. The previous example becomes:
+
+```yaml
+apiVersion: serving.knative.dev/v1
+kind: Service
+metadata:
+  name: example-service
+  namespace: default
+  annotations:
+    queue.sidecar.serving.knative.dev/cpu-resource-request: "1"
+    queue.sidecar.serving.knative.dev/cpu-resource-limit: "2"
+    queue.sidecar.serving.knative.dev/memory-resource-request: "1Gi"
+    queue.sidecar.serving.knative.dev/memory-resource-limit: "2Gi"
+    queue.sidecar.serving.knative.dev/ephemeral-storage-resource-request: "400Mi"
+    queue.sidecar.serving.knative.dev/ephemeral-storage-resource-limit: "450Mi"
+spec:
+  template:
+    spec:
+...
+```
+
+Alternatively, you could use a special annotation `queue.sidecar.serving.knative.dev/resource-percentage` that calculates the Queue Proxy resources as a percentage of the application's container.
+In this case there are min, max boundaries applied to the cpu and memory resource requirements:
+
+
+| Resource Requirements                               | Min     | Max     |
+|-------------------------------------------|---------|---------|
+| Cpu  Request   |  25m    |   100m  |
+| Cpu Limit |  40m    |   500m  |
+| Memory  Request   |  50Mi    |   200Mi  |
+| Memory Limit |  200Mi    |   500Mi  |
+
+
+!!! note
+    If the user simultaneously sets a percentage annotation and a specific resource value via the corresponding resource annotation then the latter takes precedence.
+
+!!! warning
+    The `queue.sidecar.serving.knative.dev/resource-percentage` annotation is now deprecated and will be removed in future versions.
+
+### Additional resources
 
 * For more information requests and limits for Kubernetes resources, see [Managing Resources for Containers](https://kubernetes.io/docs/concepts/configuration/manage-resources-containers/).