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kvm:set_cpu_shares_for_live_running_instance_permanently [2020/08/19 11:52] – 192.168.1.1kvm:set_cpu_shares_for_live_running_instance_permanently [2020/08/19 12:01] (current) – 192.168.1.1
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-====== KVM - Set CPU Shares For Live Running Instance Permanently ======+====== KVM - Set CPU Shares for Live Running Instance Permanently ======
  
 <code bash> <code bash>
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 **NOTE:**  KVM represents each virtual CPU as a thread in the host Linux system, actually as a thread in the QEMU process. **NOTE:**  KVM represents each virtual CPU as a thread in the host Linux system, actually as a thread in the QEMU process.
  
-On Linux, you can use **taskset** to force specific threads onto specific CPUs.  So that will let you assign one VCPU to one physical CPU and two VCPUs to another. See, for example, https://groups.google.com/forum/#!topic/linuxkernelnewbies/qs5IiIA4xnw.+On Linux, you can use **taskset** to force specific threads onto specific CPUs.  So that will let you assign one VCPU to one physical CPU and two VCPUs to another.
  
  
  
-A virtual CPU equates to 1 physical core, but when your VM attempts to process something, it can potentially run on any of the cores that happen to be available at that moment. The scheduler handles this, and the VM is not aware of it. You can assign multiple vCPUs to a VM which allows it to run concurrently across several cores.+A virtual CPU equates to 1 physical core, but when your VM attempts to process something, it can potentially run on any of the actual cores that happen to be available at that moment. The scheduler handles this, and the VM is not aware of it. You can assign multiple vCPUs to a VM which allows it to run concurrently across several cores.
  
 Cores are shared between all VMs as needed, so you could have a 4-core system, and 10 VMs running on it with 2 vCPUs assigned to each. VMs share all the cores in your system quite efficiently as determined by the scheduler. This is one of the main benefits of virtualization - making the most use of under-subscribed resources to power multiple OS instances. Cores are shared between all VMs as needed, so you could have a 4-core system, and 10 VMs running on it with 2 vCPUs assigned to each. VMs share all the cores in your system quite efficiently as determined by the scheduler. This is one of the main benefits of virtualization - making the most use of under-subscribed resources to power multiple OS instances.
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 ===== References ===== ===== References =====
 +
 +[[http://www.linux-kvm.com/content/virsh-kvm-cpu-affinity-problems|virsh kvm CPU affinity problems]]
 +
 +[[http://www.linux-kvm.com/content/some-new-kvm-options-boot-order-and-process-name|Some new kvm options: boot order and process name]]
  
 https://stackoverflow.com/questions/47621257/kvm-cpu-share-priority-overselling https://stackoverflow.com/questions/47621257/kvm-cpu-share-priority-overselling
kvm/set_cpu_shares_for_live_running_instance_permanently.1597837923.txt.gz · Last modified: 2020/08/19 11:52 by 192.168.1.1
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