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  1. OpenShift Virtualization
  2. CNV-64201

Multi IOthreads cannot be used with isolateEmulatorThread

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      Description of problem:

      If you configure multiple IOthreads, ex:
      
              ioThreadsPolicy: supplementalPool
              ioThreads:
                supplementalPoolThreadCount: 4
      
      and the VM definition includes:
      isolateEmulatorThread: true
      
      the VM will fail to start with an error like:
      
      {"component":"virt-launcher","level":"error","msg":"cannot set CPU affinity on process 844: Invalid argument","pos":"virProcessSetAffinity:550","subcomponent":"libvirt","thread":"28","timestamp":"2025-06-23T14:51:41.816000Z"}

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

      4.19

      How reproducible:

      always

      Steps to Reproduce:

      1. Use highperformance template VM
      2. Add supplementalPool & supplementalPoolThreadCount > 1

      Actual results:

      VM fails to start

      Expected results:

      At the least should probably warn / prevent this in a VM config validation check for now?
      
      Otherwise a "full" solution will take more work to pin IOthreads to additional host cpus beyond the single emulator thread... 

              rh-ee-dsanatar Danny Sanatar
              jhopper@redhat.com Jenifer Abrams
              Kate Shvaika Kate Shvaika
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                Created:
                Updated: