From: Stefan Sterz Date: Thu, 21 Mar 2024 15:50:43 +0000 (+0100) Subject: qm: multiqueue specify that it needs to be vCPUs not cores X-Git-Url: https://git.proxmox.com/?p=pve-docs.git;a=commitdiff_plain;h=3d565359211405847a7a0d9aba35e43d7604e433 qm: multiqueue specify that it needs to be vCPUs not cores 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 --- 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