[ovs-dev] [PATCH v4 1/3] doc: Move vhost tx retry info to separate section.

Ian Stokes ian.stokes at intel.com
Tue Jul 2 20:17:57 UTC 2019


On 7/2/2019 1:32 AM, Kevin Traynor wrote:
> vhost tx retry is applicable to vhost-user and vhost-user-client,
> but was in the section that compares them. Also, moved further
> down the doc as prefer to have more fundamental info about vhost
> nearer the top.
> 
> Fixes: 6d6513bfc657 ("doc: Add info on vhost tx retries.")
> Reported-by: David Marchand <david.marchand at redhat.com>
> Signed-off-by: Kevin Traynor <ktraynor at redhat.com>
> ---
>   Documentation/topics/dpdk/vhost-user.rst | 72 ++++++++++++------------
>   1 file changed, 36 insertions(+), 36 deletions(-)
> 
> diff --git a/Documentation/topics/dpdk/vhost-user.rst b/Documentation/topics/dpdk/vhost-user.rst
> index a6cf9d1cc..5f393aced 100644
> --- a/Documentation/topics/dpdk/vhost-user.rst
> +++ b/Documentation/topics/dpdk/vhost-user.rst
> @@ -76,40 +76,4 @@ mode ports require QEMU version 2.7.  Ports of type vhost-user are currently
>   deprecated and will be removed in a future release.
>   
> -vhost tx retries
> -~~~~~~~~~~~~~~~~
> -
> -When sending a batch of packets to a vhost-user or vhost-user-client interface,
> -it may happen that some but not all of the packets in the batch are able to be
> -sent to the guest. This is often because there is not enough free descriptors
> -in the virtqueue for all the packets in the batch to be sent. In this case
> -there will be a retry, with a default maximum of 8 occurring. If at any time no
> -packets can be sent, it may mean the guest is not accepting packets, so there
> -are no (more) retries.
> -
> -.. note::
> -
> -  Maximum vhost tx batch size is defined by NETDEV_MAX_BURST, and is currently
> -  as 32.
> -
> -Tx Retries may be reduced or even avoided by some external configuration, such
> -as increasing the virtqueue size through the ``rx_queue_size`` parameter
> -introduced in QEMU 2.7.0 / libvirt 2.3.0::
> -
> -  <interface type='vhostuser'>
> -      <mac address='56:48:4f:53:54:01'/>
> -      <source type='unix' path='/tmp/dpdkvhostclient0' mode='server'/>
> -      <model type='virtio'/>
> -      <driver name='vhost' rx_queue_size='1024' tx_queue_size='1024'/>
> -      <address type='pci' domain='0x0000' bus='0x00' slot='0x10' function='0x0'/>
> -  </interface>
> -
> -The guest application will also need need to provide enough descriptors. For
> -example with ``testpmd`` the command line argument can be used::
> -
> - --rxd=1024 --txd=1024
> -
> -The guest should also have sufficient cores dedicated for consuming and
> -processing packets at the required rate.
> -
>   .. _dpdk-vhost-user:
>   
> @@ -521,4 +485,40 @@ DPDK vHost User ports can be configured to use Jumbo Frames. For more
>   information, refer to :doc:`jumbo-frames`.
>   
> +vhost tx retries
> +----------------
> +
> +When sending a batch of packets to a vhost-user or vhost-user-client interface,
> +it may happen that some but not all of the packets in the batch are able to be
> +sent to the guest. This is often because there is not enough free descriptors
> +in the virtqueue for all the packets in the batch to be sent. In this case
> +there will be a retry, with a default maximum of 8 occurring. If at any time no
> +packets can be sent, it may mean the guest is not accepting packets, so there
> +are no (more) retries.
> +
> +.. note::
> +
> +  Maximum vhost tx batch size is defined by NETDEV_MAX_BURST, and is currently
> +  as 32.
> +
> +Tx Retries may be reduced or even avoided by some external configuration, such
> +as increasing the virtqueue size through the ``rx_queue_size`` parameter
> +introduced in QEMU 2.7.0 / libvirt 2.3.0::
> +
> +  <interface type='vhostuser'>
> +      <mac address='56:48:4f:53:54:01'/>
> +      <source type='unix' path='/tmp/dpdkvhostclient0' mode='server'/>
> +      <model type='virtio'/>
> +      <driver name='vhost' rx_queue_size='1024' tx_queue_size='1024'/>
> +      <address type='pci' domain='0x0000' bus='0x00' slot='0x10' function='0x0'/>
> +  </interface>
> +
> +The guest application will also need need to provide enough descriptors. For
> +example with ``testpmd`` the command line argument can be used::
> +
> + --rxd=1024 --txd=1024
> +
> +The guest should also have sufficient cores dedicated for consuming and
> +processing packets at the required rate.
> +

Looks ok to me.

@David as this was suggested by you, are you happy with the change?

Thanks
Ian




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