On Wed, 27 May 2020 11:29:21 +0100 Stefan Hajnoczi <stefa...@redhat.com> wrote:
> Multi-queue devices achieve the best performance when each vCPU has a > dedicated queue. This ensures that virtqueue used notifications are > handled on the same vCPU that submitted virtqueue buffers. When another > vCPU handles the the notification an IPI will be necessary to wake the > submission vCPU and this incurs a performance overhead. > > Provide a helper function that virtio-pci devices will use in later > patches to automatically select the optimal number of queues. > > Signed-off-by: Stefan Hajnoczi <stefa...@redhat.com> > --- > hw/virtio/virtio-pci.h | 9 +++++++++ > hw/virtio/virtio-pci.c | 7 +++++++ > 2 files changed, 16 insertions(+) That looks like a good idea, since the policy can be easily tweaked in one place later. For ccw, I don't see a good way to arrive at an optimal number of queues. Is there something we should do for mmio? If yes, should this be a callback in VirtioBusClass?
