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

David Marchand david.marchand at redhat.com
Wed Jul 3 07:11:12 UTC 2019


On Tue, Jul 2, 2019 at 10:18 PM Ian Stokes <ian.stokes at intel.com> wrote:

> 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?
>

Yes, thanks.
Reviewed-by: David Marchand <david.marchand at redhat.com>


-- 
David Marchand


More information about the dev mailing list