Commits on Nov 15, 2024

1. Enable the vhost backend for the virtio-net interfaces in the KVM hyp… …

   …ervisor
   
   Using vhost as the backend for virtio-net in a QEMU/KVM setup bypasses QEMU's
   user-space network packet processing by moving packet handling directly into
   the Linux kernel. Normally, QEMU would process network I/O in user space,
   which incurs significant CPU overhead and latency due to frequent context
   switching between user space (QEMU) and kernel space. With vhost, packet
   processing is handled by a dedicated kernel thread, avoiding QEMU for most
   networking tasks. This direct kernel handling minimizes the need for QEMU’s
   intervention, resulting in lower latency, higher throughput, and better
   CPU efficiency for network-intensive applications running on virtual machines.
   
   Using vhost is a clear choice with no downsides, as it is already included
   in eve-kernel and does not increase the EVE image size. Reducing QEMU overhead
   is especially important for EVE, where we enforce cgroup CPU quotas to limit
   an application to using no more than N CPUs at a time, with N being the number
   of vCPUs assigned to the app in its configuration (see pkg/pillar/containerd/oci.go,
   method UpdateFromDomain()). These CPU quotas apply to both the application and
   QEMU itself, so removing QEMU from packet processing is essential to prevent
   it from consuming CPU cycles needed by the application.
   
   Signed-off-by: Milan Lenco <[email protected]>

   

   milan-zededa committed Nov 15, 2024
   Configuration menu

   • View commit details
   • Copy full SHA for ca27d1d
   • Browse repository at this point

   Copy the full SHA

   ca27d1d View commit details

   Browse the repository at this point in the history