[libvirt] [PATCH] qemu: multiqueue for ccw devices

[Laine Stump]

On 05/06/2015 10:07 AM, Boris Fiuczynski wrote:
> Allow ccw devices to be used with multiqueues.

Can you provide a bit more information in the commit log on the reason
for this difference? Is the vectors= option not supported when using the
ccw bus? Or is is simply not needed because it's determined
automatically based on the number of fd's that are passed in?


>
> Signed-off-by: Boris Fiuczynski <fiuczy at linux.vnet.ibm.com>
> Reviewed-by: Matthew Rosato <mjrosato at linux.vnet.ibm.com>
> Reviewed-by: Daniel Hansel <daniel.hansel at linux.vnet.ibm.com>
> Reviewed-by: Cornelia Huck <cornelia.huck at de.ibm.comCornelia Huck <cornelia.huck at de.ibm.com>>
>
> ---
>  src/qemu/qemu_command.c | 10 +++++++---
>  1 file changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
> index 2137985..0205831 100644
> --- a/src/qemu/qemu_command.c
> +++ b/src/qemu/qemu_command.c
> @@ -5062,9 +5062,13 @@ qemuBuildNicDevStr(virDomainDefPtr def,
>          }
>      }
>      if (usingVirtio && vhostfdSize > 1) {
> -        /* As advised at http://www.linux-kvm.org/page/Multiqueue
> -         * we should add vectors=2*N+2 where N is the vhostfdSize */
> -        virBufferAsprintf(&buf, ",mq=on,vectors=%zu", 2 * vhostfdSize + 2);
> +        if (net->info.type == VIR_DOMAIN_DEVICE_ADDRESS_TYPE_CCW) {
> +            virBufferAsprintf(&buf, ",mq=on");
> +        } else {
> +            /* As advised at http://www.linux-kvm.org/page/Multiqueue
> +             * we should add vectors=2*N+2 where N is the vhostfdSize */
> +            virBufferAsprintf(&buf, ",mq=on,vectors=%zu", 2 * vhostfdSize + 2);
> +        }
>      }
>      if (vlan == -1)
>          virBufferAsprintf(&buf, ",netdev=host%s", net->info.alias);