[pve-devel] [PATCH docs 1/2] qm: multiqueue specify that it needs to be vCPUs not cores

[pve-devel] [PATCH docs 1/2] qm: multiqueue specify that it needs to be vCPUs not cores

[Stefan Sterz]

total number of cores != vCPUs if there is more than one socket
configured. according to the redhat docs it should be vCPUs not cores:

> Multi-queue virtio-net provides the greatest performance benefit when:
> [..]
> - The number of queues is equal to the number of vCPUs.

https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/virtualization_tuning_and_optimization_guide/sect-virtualization_tuning_optimization_guide-networking-techniques#sect-Virtualization_Tuning_Optimization_Guide-Networking-Multi-queue_virtio-net
Signed-off-by: Stefan Sterz <s.sterz@proxmox.com>
---
 qm.adoc | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/qm.adoc b/qm.adoc
index 1170dd1..8630419 100644
--- a/qm.adoc
+++ b/qm.adoc
@@ -770,14 +770,15 @@ vhost driver. With this option activated, it is possible to pass _multiple_
 network queues to the host kernel for each NIC.
 
 //https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/Virtualization_Tuning_and_Optimization_Guide/sect-Virtualization_Tuning_Optimization_Guide-Networking-Techniques.html#sect-Virtualization_Tuning_Optimization_Guide-Networking-Multi-queue_virtio-net
-When using Multiqueue, it is recommended to set it to a value equal
-to the number of Total Cores of your guest. You also need to set in
-the VM the number of multi-purpose channels on each VirtIO NIC with the ethtool
-command:
+When using Multiqueue, it is recommended to set it to a value equal to the
+number of vCPUs of your guest. Remember that the number of vCPUs is the number
+of sockets times the number of cores configured for the VM. You also need to set
+the number of multi-purpose channels on each VirtIO NIC in the VM with this
+ethtool command:
 
 `ethtool -L ens1 combined X`
 
-where X is the number of the number of vcpus of the VM.
+where X is the number of the number of vCPUs of the VM.
 
 You should note that setting the Multiqueue parameter to a value greater
 than one will increase the CPU load on the host and guest systems as the
-- 
2.39.2

[pve-devel] [PATCH docs 2/2] qm: add documentation on configuring multiqueue for windows guests

[Stefan Sterz]

Signed-off-by: Stefan Sterz <s.sterz@proxmox.com>
---
 qm.adoc | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/qm.adoc b/qm.adoc
index 8630419..711fa3f 100644
--- a/qm.adoc
+++ b/qm.adoc
@@ -780,6 +780,16 @@ ethtool command:
 
 where X is the number of the number of vCPUs of the VM.
 
+To configure a Windows guest for Multiqueue install the
+https://fedorapeople.org/groups/virt/virtio-win/direct-downloads/stable-virtio/virtio-win.iso[
+Redhat VirtIO Ethernet Adapter drivers], then adapt the NIC's configuration as
+follows. Open the device manager, right click the NIC under "Network adapters",
+and select "Properties". Then open the "Advanced" tab and select "Receive Side
+Scaling" from the list on the left. Make sure it is set to "Enabled". Next,
+navigate to "Maximum number of RSS Queues" in the list and set it to the number
+of vCPUs of your VM. Once you verified that the settings are correct, click "OK"
+to confirm them.
+
 You should note that setting the Multiqueue parameter to a value greater
 than one will increase the CPU load on the host and guest systems as the
 traffic increases. We recommend to set this option only when the VM has to
-- 
2.39.2

[pve-devel] applied: [PATCH docs 1/2] qm: multiqueue specify that it needs to be vCPUs not cores

[Aaron Lauterer]

On  2024-03-21  16:50, Stefan Sterz wrote:
> total number of cores != vCPUs if there is more than one socket
> configured. according to the redhat docs it should be vCPUs not cores:
> 
>> Multi-queue virtio-net provides the greatest performance benefit when:
>> [..]
>> - The number of queues is equal to the number of vCPUs.
> 
> https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/virtualization_tuning_and_optimization_guide/sect-virtualization_tuning_optimization_guide-networking-techniques#sect-Virtualization_Tuning_Optimization_Guide-Networking-Multi-queue_virtio-net
> Signed-off-by: Stefan Sterz <s.sterz@proxmox.com>
> ---
>   qm.adoc | 11 ++++++-----
>   1 file changed, 6 insertions(+), 5 deletions(-)
> 
>

applied series with a small follow up linking to our VirtIO wiki page 
instead of directly to the latest ISO

thanks!