I am using a Behringer UMC204HD as a USB ASIO DAC to record guitars/voice and was noticing some underruns on a Win10 guest. Host is a Xeon E5-2667v2, on archlinux 4.19.12.
Two things helped a great deal for me: 1) setting the cpu gorvernor to performance on the host 2) assigning the IRQ of the USB controller (which the DAC sits on) to one of the cores that are passed to the guest. You cannot do this with libvirt, it has to be done on the host with a script. E.g. if you pass cpus 1-7,9-15 on the host to the guest: ----------8<---------- for i in $(grep vfio /proc/interrupts \ | awk '{print $1}' | sed -e 's/://'); do echo 1-7,9-15 | tee /proc/irq/$i/smp_affinity_list done ----------8<---------- Best, George _______________________________________________ vfio-users mailing list vfio-users@redhat.com https://www.redhat.com/mailman/listinfo/vfio-users