[ovs-dev] [PATCH v2] INSTALL.DPDK: Add notes regarding vhost multiq configuration.

Flavio Leitner fbl at sysclose.org
Fri Feb 12 04:57:47 UTC 2016


On Tue,  9 Feb 2016 14:40:53 +0000
Ian Stokes <ian.stokes at intel.com> wrote:

> Linux kernel network devices in a guest should have the number of
> multi-purpose channels configured when used with DPDK multiqueue on the host.
> This commit adds an example of how this can be done. Also add QEMU 2.5
> requirements for multiqueue with DPDK in NEWS.
> 
> Signed-off-by: Ian Stokes <ian.stokes at intel.com>
> ---
>  INSTALL.DPDK.md |   17 +++++++++++++++++
>  NEWS            |    2 +-
>  2 files changed, 18 insertions(+), 1 deletions(-)
> 
> diff --git a/INSTALL.DPDK.md b/INSTALL.DPDK.md
> index d892788..e9f9acc 100644
> --- a/INSTALL.DPDK.md
> +++ b/INSTALL.DPDK.md
> @@ -586,6 +586,23 @@ Follow the steps below to attach vhost-user port(s) to a VM.
>     -device virtio-net-pci,mac=00:00:00:00:00:02,netdev=mynet2,mq=on,vectors=$v
>     ```
>  
> +   Also, the driver in the guest operating system must be configured to use
> +   the exact same number of queues. If the number of queues is less than $q,
> +   then packets that are enqueued to queues unused by guest will not be
> +   received.


It would be good to provide these details in the documentation. However, if the
patch http://openvswitch.org/pipermail/dev/2016-February/066066.html gets merged,
the above paragraph needs to be reworded a bit.

Thanks.
--
fbl

> +
> +   This can be done for the Linux kernel virtio-net driver with:
> +
> +   ```
> +   ethtool -L <DEV> combined <$q>
> +   ```
> +
> +   A note on the command above:
> +
> +   `-L`: Changes the numbers of channels of the specified network device
> +
> +   `combined`: Changes the number of multi-purpose channels.
> +
>  DPDK vhost-cuse:
>  ----------------
>  
> diff --git a/NEWS b/NEWS
> index 3e33871..2d1b8fb 100644
> --- a/NEWS
> +++ b/NEWS
> @@ -55,7 +55,7 @@ v2.5.0 - xx xxx xxxx
>     - DPDK:
>       * Requires DPDK 2.2
>       * Added multiqueue support to vhost-user
> -
> +     * Note: QEMU 2.5+ required for multiqueue support
>  
>  v2.4.0 - 20 Aug 2015
>  ---------------------





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