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  1. OpenShift Bugs
  2. OCPBUGS-17532

[OVN-IC] High CPU usage of ovnkube-node on the worker nodes during resource deletion

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      Description of problem:

      We are running a test that has two distinct phases - a creation/ramp-up phase that creates a lot of resources like pods, services, network policies, namespaces etc and then a churn phase that deletes and recreates 10% of all resources created for about an hour to mimic a cluster in steady state. We notice that ovnkube-node container on the worker nodes is very spiky during the deletion phase as compared to the create phase in OVN-IC. We see a lot more CPU usage during the deletion actions as part of the "churn" phase when compared to the creation actions in the ramp-up phase.

      Version-Release number of selected component (if applicable):

      4.14.0-0.nightly-2023-08-08-094653

      How reproducible:

      100%

      Steps to Reproduce:

      1. Use kube-burner to run this workload on a ROSA/Self-managed OCP cluster
      2. https://github.com/smalleni/kube-burner/commit/d2b4f20f1de20ca0e70d71070331ae61e15698a0 
      3. kube-burner ocp cluster-density-v2 --iterations=650

      You can also reproduce this by running the regular clcuster-density-v2 workload with churn=true

      Actual results:

      High CPU usage during the churn (resource deletion/re-creation) phase

      Expected results:

      CPU usage should be lower

      Additional info:

      The biggest difference in CPU usage when comparing the ovnkube-node pod seems to be coming from the CPU usage of the ovnkube-node container during creation and deletion. The other containers are not contributing much to the difference.

      ovnkube-node container CPU usage during creation phase: https://grafana.rdu2.scalelab.redhat.com:3000/dashboard/snapshot/FemcDupRa7aKUZMWqfu9xSGoOK7HwmxT

      ovnkube-node container CPU usage during delete/recreate operation: https://grafana.rdu2.scalelab.redhat.com:3000/dashboard/snapshot/VxNUFvyPQYvSgnQSaGbncHs3yJmpkX0Y

              npinaeva@redhat.com Nadia Pinaeva
              smalleni@redhat.com Sai Sindhur Malleni
              Anurag Saxena Anurag Saxena
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                Created:
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