My KVM Forum 2024 talk "IOThread Virtqueue Mapping: Improving virtio-blk SMP scalability in QEMU" is now available on YouTube. The slides are also available here.
IOThread Virtqueue Mapping is a new QEMU feature for configuring multiple IOThreads that will handle a virtio-blk device's virtqueues. This means QEMU can take advantage of the host's Linux multi-queue block layer and assign CPUs to I/O processing. Giving additional resources to virtio-blk emulation allows QEMU to achieve higher IOPS and saturate fast local NVMe drives. This is especially important for applications that submit I/O on many vCPUs simultaneously - a workload that QEMU had trouble keeping up with in the past.
You can read more about IOThread Virtqueue Mapping in this Red Hat blog post.
