[ovirt-devel] Discussion VM CPU pinning and NUMA CPU pinning

[Gilad Chaplik]

Can you please be more specific on how to model RESTful API, with regards to CPU and CPU-pinning.

Thanks, 
Gilad.


----- Original Message -----
> From: "Chuan Liao (Jason Liao, HPservers-Core-OE-PSC)" <chuan.liao at hp.com>
> To: devel at ovirt.org
> Cc: "Doron Fediuck" <dfediuck at redhat.com>, "Gilad Chaplik" <gchaplik at redhat.com>, "Martin Sivák" <msivak at redhat.com>,
> "Juan Hernandez" <juan.hernandez at redhat.com>, "Malini Rao" <mrao at redhat.com>, "Chegu Vinod" <chegu_vinod at hp.com>,
> "Shang-Chun Liang (David Liang, HPservers-Core-OE-PSC)" <shangchun.liang at hp.com>, "Xiao-Lei Shi (Bruce, HP
> Servers-PSC-CQ)" <xiao-lei.shi at hp.com>
> Sent: Thursday, May 15, 2014 2:50:23 PM
> Subject: Discussion VM CPU pinning and NUMA CPU pinning
> 
> Hi All,
> 
> Now we are working on the NUMA tune feature development for oVirt 3.5. This
> feature allow user to configure the vCPU pining according to host CPU/NUMA
> topology to get the best performance for created VM. But this will impact
> the current function of vCPU pining. Now, we are looking for a solution to
> consolidate the conflict. We want to start an open discussion about VM CPU
> pinning (the current design) and NUMA CPU pining (new feature we are working
> on) in developer list:
> 
> Background:
> Concept:
> 
> 1.      VM CPU pinning: the exist feature in current oVirt, which allow user
> to configure the VM vCPU pinning over ovirt, user can configure vCPU pining
> independently without NUMA tune.
> 
> 2.      NUMA CPU pinning: allow user to configure the vCPU pining according
> to host NUMA topology to get the best performance for created VM
> 
> 3.      vNode: Virtual NUMA node ( User configured )
> 
> 4.      pNode: host physical NUMA node ( Get capability from host )
> Notice:
> 
> 1.      NUMA tuning feature and CPU pinning feature are individually in
> libvirt ( ovirt backend ).
> 
> 2.      User could configure VM CPU pining individually without NUMA tune
> setup.
> 
> 3.      When configuring NUMA tuning feature, user need to configure VM NUMA
> tuning ( vNode pinto pNode & tuning mode ) and VM CPU pinning ( NUMA
> included ) to get optimized VM performance, otherwise VM will have low
> performance.
> 
> We have two proposal now for this issue. Please give us some comments and
> your feedback, thanks.
> 
> Solution 1:
>          GUI:
> Transform between the CPU pinning text and a structure which will be used in
> NUMA CPU pinning configure page.
>     And then save the CPU pinning text to the current VM CPU pinning field of
>     VM.
>          Restful:
> Transform between the CPU pinning text and a structure which will be used in
> restful NUMA CPU pinning.
> And then save the CPU pinning text to the current VM CPU pinning field of VM.
>          Broker:
> Remove temporary solution(See the current implementation as below) and follow
> previous cpupin configuration procedure.
> 
> Solution 2:
>          GUI:
> If current VM CPU pinning is configured, when user open NUMA CPU pinning
> configure page, he will get a warning message. If he continues to configure
> NUMA CPU pinning and save the data, the current VM CPU pinning
> configuration will be cleared.
> NUMA CPU pinning configured data will be saved as new structure individually
> without changing current VM CPU pinning configuration.
>          Restful:
> Configure NUMA CPU pinning and then save the data with the new NUMA CPU
> pinning structure.
>          Entity and Database:
> Individually NUMA CPU pinning entities and data structure.
>          Broker:
>          NUMA CPU pinning configuration will be first considered to use. If
>          it's not configured, it will use the current VM CPU pinning.
> 
> Solution 1 The CPU pining data is consistent but the code logic is very
> complex.
> Solution 2 have better adaptive and better data structure. This is the way we
> preferred.
> 
> We are appreciated that anybody could give us your comments or the better
> solution you have.
> 
> 
> 
> The below is the current implementation for your reference:
> VM CPU pinning feature
>          GUI:
> User input vCPU pining configure data with formatted text.
>          Restful:
> User configure CpuTune and VCpuPin model with mapper to CPU pinning text.
>          Entity and Database:
> CPU pinning is String property.
>          Broker:
> Generate structure of cputune ( libvirt format ) from CPU pining string
> property.
> NUMA tuning feature
>          GUI:
> User can drag & drop virtual NUMA node to host NUMA node ( pin to or remove
> pin to ).
>          Restful:
> Add/update/remove virtual NUMA node with property of pin to host NUMA node
> index.
>          Design NUMACPU model under NUMA node for extend.
>          Entity and Database:
> Individually NUMA node entities ( vNode extend pNode ) and store procedure.
>          Broker:
> Generate structure of numatune, cpu/numa ( libvirt format ) from NUMA node
> entities.
> Temporary solution prevent Notice 3
>          Broker:
> Generate right structure of cputune ( libivirt format ) from NUMA node
> entities ( vNode pinto pNode )
>          Limitation:
> This structure of cputune will not get the best performance of vNode.
> 
> Best Regards,
> Jason Liao
> 
>