[ovirt-devel] high performance VM preset

[Martin Sivak]

Or maybe on NUMA nodes.

On Wed, May 24, 2017 at 3:03 PM, Martin Sivak <msivak at redhat.com> wrote:
>> In order to maximize performance we may also want to limit the number of
>> other VMs (either regular or high performance) running on the same
>> host. This to minimize the interference and the resource stealing.
>>
>>
>> In the extreme case, just the selected high performance VM would be
>> allowed to run on one suitable host.
>
> I would base this on cores. You can have two HPF VMs when each is
> pinned to distinct set of CPUs.
>
> Martin
>
> On Wed, May 24, 2017 at 2:11 PM, Francesco Romani <fromani at redhat.com> wrote:
>> On 05/24/2017 12:57 PM, Michal Skrivanek wrote:
>>> Hi all,
>>> we plan to work on an improvement in VM definition for high performance workloads which do not require desktop-class devices and generally favor highest possible performance in expense of less flexibility.
>>> We’re thinking of adding a new VM preset in addition to current Desktop and Server in New VM dialog, which would automatically pre-select existing options in the right way, and suggest/warn on suboptimal configuration
>>> All the presets and warning can be changed and ignored. There are few things we already identified as boosting performance and/or minimize the complexity of the VM, so we plan the preset to:
>>> - remove all graphical consoles and set the VM as headless, making it accessible by serial console.
>>> - disable all USB.
>>> - disable soundcard.
>>> - enable I/O Threads, just one for all disks by default.
>>> - set host cpu passthrough (effectively disabling VM live migration), add I/O Thread pinning in a similar way as the existing CPU pinning.
>>> We plan the following checks and suggest to perform CPU pinning, host topology == guest topology (number of cores per socket and threads per core should match), NUMA topology host and guest match, check and suggest the I/O threads pinning.
>>> A popup on a VM dialog save seems suitable.
>>>
>>> currently identified task and status can be followed on trello card[1]
>>>
>>> Please share your thoughts, questions, any kind of feedback…
>>
>> In order to maximize performance we may also want to limit the number of
>> other VMs (either regular or high performance) running on the same
>> host. This to minimize the interference and the resource stealing.
>>
>>
>> In the extreme case, just the selected high performance VM would be
>> allowed to run on one suitable host.
>>
>> Bests,
>>
>> --
>> Francesco Romani
>> Senior SW Eng., Virtualization R&D
>> Red Hat
>> IRC: fromani github: @fromanirh
>>
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