Multiqueue

[maorbari]

Hi, I have some questions.

1. If the multiqueue is empty, it will have any default value or is it disabled?
2. I can't set more than 8 in multiqueue at GUI, why? There is any reason?
3. There is an option to make multiqueue to equal to vCPU number by default? So if I will change the vCPU number, the multiqueue changed according to the new value.
4. There is any hardware requirements for using multiqueue?
5. How to test if multiqueue is really work and affective?

Thank you!

 

[mira]

Currently there's a hardcoded limit of 8 in the GUI and 16 when using the API/CLI. The default is `1`.

Do you need more than that? For each queue a new kernel thread is created and used, which can quickly lead to lots of additional load.

The queue value has to be managed manually when the number of cores changes.

You have to enable the usage of queues inside the guest as well, see our docs [0] for details on how to do that.


[0] https://pve.proxmox.com/pve-docs/pve-admin-guide.html#qm_virtual_machines_settings (10.2.7)

 

[spirit]

@mira I have send patch to pve-devel mailing to increase the max value to 128, which is the maximum supported.

(but indeed, you need 128 cores in the vm to have good performance, as you need 1core by thread/queue, or you'll have context switch).


BTW, about the doc, virtio drivers autoconfigure queues since some years, so no need to tune with ethtool anymore.

 

[DC-CA1]

Currently there's a hardcoded limit of 8 in the GUI and 16 when using the API/CLI. The default is `1`.

Do you need more than that? For each queue a new kernel thread is created and used, which can quickly lead to lots of additional load.

The queue value has to be managed manually when the number of cores changes.

You have to enable the usage of queues inside the guest as well, see our docs [0] for details on how to do that.


[0] https://pve.proxmox.com/pve-docs/pve-admin-guide.html#qm_virtual_machines_settings (10.2.7)

@mira can you tel me if this can be related to my issue here ?

https://forum.proxmox.com/threads/m...ith-32-multiqueue-vitrio-on-migration.122722/

strangly the vm boot withtout any error with 32 vmultiqueue at origin so its confusing ,