Update linux auto-pause result with improved method

hack/benchmark/cpu_usage/auto_pause/README.md

@@ -5,8 +5,8 @@ These scripts are for the benchmark of cpu usage, minikube vs kind vs k3d.
  * `update_summary.sh`: create one summary csv file of each drivers and products
  * `chart.go`: create bar chart graph as a png file
  
-In `benchmark_local_k8s.sh`, we compare minikube drivers(hyperkit, virtualbox, docker) and kind, k3d, Docker for Mac Kubernetes in case of macOS.   
-In `benchmark_local_k8s.sh`, we compare minikube drivers(kvm2, virtualbox, docker) and kind, k3d in case of Linux.   
+In `benchmark_local_k8s.sh`, we compare minikube drivers(hyperkit, virtualbox, docker with auto-pause addon) and kind, k3d, Docker for Mac Kubernetes in case of macOS.   
+In `benchmark_local_k8s.sh`, we compare minikube drivers(kvm2, virtualbox, docker with auto-pause addon) and kind, k3d in case of Linux.   
 `benchmark_local_k8s.sh` take these steps to measure `auto-pause` vs. `non auto-pause`.   
 
  1. start each local kubernetes tool

site/content/en/docs/benchmarks/cpuUsage/linux/_index.md

@@ -12,6 +12,9 @@ This chart was measured only after the start without deploying any pods.
 
 ![idleOnly](/images/benchmarks/cpuUsage/idleOnly/linux.png)
 
+NOTE: the benchmark environment uses GCE with nested virtualization. This may affect virtual machine's overhead.   
+https://cloud.google.com/compute/docs/instances/enable-nested-virtualization-vm-instances   
+
 ## CPU% Busy Overhead - With Auto Pause vs. Non Auto Pause
 
 This chart shows each tool's CPU busy overhead percentage with auto-pause addon.   
@@ -20,11 +23,19 @@ This chart was measured with the following steps.
 By these steps, we compare CPU usage with auto-pause vs. non-auto-pause.  
 
  1. start each local kubernetes tool
- 2. deploy sample application(nginx deployment)
+ 2. deploy sample application(nginx deployment) to each tool
  3. wait 1 minute without anything
  4. measure No.3 idle CPU usage with [cstat](https://github.com/tstromberg/cstat)
- 5. enable auto-pause addons(only if tool is minikube)
- 6. wait 3 minute without anything
- 7. measure No.6 idle CPU usage with [cstat](https://github.com/tstromberg/cstat)
+ 5. if tool is minikube, enable auto-pause addon which pause control plane
+ 6. if tool is minikube, wait 1 minute so that control plane will become Paused status(It takes 1 minute to become Pause status from Stopped status)  
+ 7. if tool is minikube, verify if minikube control plane is paused
+ 8. if tool is minikube, wait 3 minute without anything
+ 9. if tool is minikube, measure No.8 idle CPU usage with [cstat](https://github.com/tstromberg/cstat)
+
+No.1-4: Initial start CPU usage with sample(nginx) deployment   
+No.5-9: Auto Paused CPU usage with sample(nginx) deployment   
  
-![autopause](/images/benchmarks/cpuUsage/autoPause/linux.png)
+![autopause](/images/benchmarks/cpuUsage/autoPause/linux.png)
+
+NOTE: the benchmark environment uses GCE with nested virtualization. This may affect virtual machine's overhead.   
+https://cloud.google.com/compute/docs/instances/enable-nested-virtualization-vm-instances