<p>I'm trying to capture the impact of enabling Horizontal Pod Autoscaler (HPA) resources on the performance of HPA, in Kubernetes. I have found a few metrics related to the HPA but find that they lack documentation. For example, the metric <code>horizontalpodautoscaler_queue_latency</code> is available but it is not clear what unit it is measured in - microseconds, milliseconds or anything else.</p>

<p>Can anyone point me to any documentation related to control plane metrics? It would be great if you can also point me to the code base of these metrics as well because I could not find any reference to control plan metrics (tried searching for <code>horizontalpodautoscaler_queue_latency</code>) in <a href="https://github.com/kubernetes/kubernetes" rel="nofollow noreferrer">https://github.com/kubernetes/kubernetes</a>.</p>

<p>Thanks a ton.</p>

<p>There is no much information about this metric, but I found this metrics is mensured in <strong>quantile</strong> and not time (milisecs, microsecs etc.).</p>

<p><a href="https://cloud.google.com/monitoring/api/metrics_anthos?hl=en" rel="nofollow noreferrer">Here</a> you can find the following:</p>

<blockquote>
  <p><strong>horizontalpodautoscaler_queue_latency_count</strong></p>
  
  <p>(Deprecated) How long an item stays in workqueuehorizontalpodautoscaler before being requested.</p>
</blockquote>

<p>Also, seems the metric is <strong>deprecated</strong>, maybe it is the reason that you cannot found too much information about.</p>
