[openstack-dev] [nova] Extra feature of vCPU allocation on demands

Jay Pipes jaypipes at gmail.com
Mon May 7 14:51:11 UTC 2018

On 05/07/2018 05:55 AM, 倪蔚辰 wrote:
> Hi, all
> I would like to propose a blueprint (not proposed yet), which is related 
> to openstack nova. I hope to have some comments by explaining my idea 
> through this e-mail. Please contact me if anyone has any comment.
> Background
> Under current OpenStack, vCPUs assigned to each VM can be configured as 
> dedicated or shared. In some scenarios, such as deploying Radio Access 
> Network VNF, the VM is required to have dedicated vCPUs to insure the 
> performance. However, in that case, each VM has a vCPU to do Guest OS 
> housekeeping. Usually, this vCPU is not a high performance required vCPU 
> and do not take high percentage of dedicated vCPU utilization. There is 
> some vCPU resources waste.
> Proposed feature
> I hope to add an extra feature to flavor extra specs. It refers to how 
> many dedicated vCPUs and how many shared vCPUs are needed for the VM. 
> When VM requires vCPU, OpenStack allocates vCPUs on demands. In the 
> background scenario, this idea can save many dedicated vCPUs which take 
> Guest OS housekeeping. And the scenario stated above is only one use 
> case for the feature. This feature potentially allows user to have more 
> flexible VM design to save CPU resource.

Please see here:



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