[ovs-dev] [PATCH v3 3/4] netdev-dpdk: Add stats for vhost tx retries.

[Flavio Leitner]

On Fri, Jun 28, 2019 at 03:21:07PM +0300, Ilya Maximets wrote:
> On 27.06.2019 14:12, Kevin Traynor wrote:
> > vhost tx retries may occur, and it can be a sign that
> > the guest is not optimally configured.
> > 
> > Add some stats so a user will know if vhost tx retries are
> > occurring and hence give a hint that guest config should be
> > examined.
> > 
> > Signed-off-by: Kevin Traynor <ktraynor at redhat.com>
> > Acked-by: Flavio Leitner <fbl at sysclose.org>
> > Acked-by: Eelco Chaudron <echaudro at redhat.com>
> > ---
> >  Documentation/topics/dpdk/vhost-user.rst | 5 +++++
> >  include/openvswitch/netdev.h             | 1 +
> >  lib/netdev-dpdk.c                        | 7 +++++--
> >  vswitchd/bridge.c                        | 3 ++-
> >  4 files changed, 13 insertions(+), 3 deletions(-)
> > 
> > diff --git a/Documentation/topics/dpdk/vhost-user.rst b/Documentation/topics/dpdk/vhost-user.rst
> > index 1dd02b8b6..3caa88231 100644
> > --- a/Documentation/topics/dpdk/vhost-user.rst
> > +++ b/Documentation/topics/dpdk/vhost-user.rst
> > @@ -112,4 +112,9 @@ The guest should also have sufficient cores dedicated for consuming and
> >  processing packets at the required rate.
> >  
> > +The amount of Tx retries on a vhost-user or vhost-user-client interface can be
> > +shown with::
> > +
> > +  ovs-vsctl get Interface dpdkvhostclient0 statistics:tx_retries
> > +
> >  .. _dpdk-vhost-user:
> >  
> > diff --git a/include/openvswitch/netdev.h b/include/openvswitch/netdev.h
> > index 0c10f7b48..4d18b9f66 100644
> > --- a/include/openvswitch/netdev.h
> > +++ b/include/openvswitch/netdev.h
> > @@ -46,4 +46,5 @@ struct netdev_stats {
> >      uint64_t multicast;         /* Multicast packets received. */
> >      uint64_t collisions;
> > +    uint64_t tx_retries;        /* Retries when unable to transmit.*/
> 
> 
> This seems very vhost specific counter.
> Maybe it's better to report it in custom_stats?

I thought we could implement retry for nics and rings if we want to
not drop any packets. Not sure if it will ever be implemented
though.

fbl