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  1. OpenShift Virtualization
  2. CNV-35859

[2252097] [DPDK checkup] tuned-adm parameters only updated after VM reboot

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      Description of problem:
      tuned-adm (and other) parameters are updated in the /proc/cmdline only if the VM is rebooted.

      Version-Release number of selected component (if applicable):
      CNV 4.14.0
      RHEL 8.7

      How reproducible:
      Always

      Steps to Reproduce:
      1.
      Create a RHEl 8.7 VM by following https://docs.openshift.com/container-platform/4.14/virt/monitoring/virt-running-cluster-checkups.html#virt-building-vm-containerdisk-image_virt-running-cluster-checkups

      2.
      Run a guest VM by applying the attached vmi-under-test.yaml.

      • Note that this VM uses the image created in the previous section.
      • This is the image that is supposed to be used for the DPDK checkup, by setting it as the value for `spec.param.trafficGenContainerDiskImage` and `spec.param.vmUnderTestContainerDiskImage`.

      3.
      After the VM is running - enter it's console and check for the /proc/cmdline:

      $ virtctl console vmi-under-test-nhkh2
      Successfully connected to vmi-under-test-nhkh2 console. The escape sequence is ^]

      [cloud-user@vmi-under-test-nhkh2 ~]$ cat /proc/cmdline
      BOOT_IMAGE=(hd0,gpt3)/boot/vmlinuz-4.18.0-425.19.2.el8_7.x86_64 root=UUID=1496f40e-6254-4df7-823c-4dc607c943f3 console=tty0 console=ttyS0,115200n8 no_timer_check net.ifnames=0 crashkernel=auto default_hugepagesz=1GB hugepagesz=1G hugepages=8 isolcpus=2-7

      4.
      Reboot the VM
      [cloud-user@vmi-under-test-nhkh2 ~]$ sudo reboot

      5.
      After the VM is up again - repeat the check from section 3:
      $ cat /proc/cmdline
      BOOT_IMAGE=(hd0,gpt3)/boot/vmlinuz-4.18.0-425.19.2.el8_7.x86_64 root=UUID=1496f40e-6254-4df7-823c-4dc607c943f3 console=tty0 console=ttyS0,115200n8 no_timer_check net.ifnames=0 crashkernel=auto default_hugepagesz=1GB hugepagesz=1G hugepages=8 isolcpus=2-7 skew_tick=1 nohz=on nohz_full=2-7 rcu_nocbs=2-7 tuned.non_isolcpus=00000003 intel_pstate=disable nosoftlockup

      Actual results:
      The following values appear only after reboot:
      skew_tick=1 nohz=on nohz_full=2-7 rcu_nocbs=2-7 tuned.non_isolcpus=00000003 intel_pstate=disable nosoftlockup

      Expected results:
      All values should be updated on the guest VM first start-up.

            ralavi@redhat.com Ram Lavi
            ysegev@redhat.com Yossi Segev
            Nir Rozen Nir Rozen
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              Created:
              Updated: