[ovs-dev] [PATCH] dpdk: announce deprecation of vhost-user server ports
Darrell Ball
dball at vmware.com
Thu Jun 8 18:13:15 UTC 2017
On 6/8/17, 6:40 AM, "Aaron Conole" <aconole at redhat.com> wrote:
Hi Darrell,
Thanks so much for the review! Comments below.
Darrell Ball <dball at vmware.com> writes:
> On 6/7/17, 3:46 PM, "Aaron Conole" <aconole at redhat.com> wrote:
>
> Since vhost-user server mode ports are the preferred mechanism for
> interconnecting Open vSwitch with VMs when using DPDK, and since there
> are currently no known use cases for vhost-user server mode ports apart
> from version incompatibilities with QEMU, announce that server mode ports
> are considered deprecated and will be removed in a future release.
>
> Cc: Ciara Loftus <ciara.loftus at intel.com>
> Cc: Kevin Traynor <ktraynor at redhat.com>
> Suggested-by: Darrell Ball <dball at vmware.com>
> Signed-off-by: Aaron Conole <aconole at redhat.com>
> ---
> Documentation/topics/dpdk/vhost-user.rst | 24 ++++++++++++++++--------
> NEWS | 2 ++
> lib/netdev-dpdk.c | 2 ++
> 3 files changed, 20 insertions(+), 8 deletions(-)
>
> diff --git a/Documentation/topics/dpdk/vhost-user.rst b/Documentation/topics/dpdk/vhost-user.rst
> index a1c19fd..9d36cf2 100644
> --- a/Documentation/topics/dpdk/vhost-user.rst
> +++ b/Documentation/topics/dpdk/vhost-user.rst
> @@ -32,13 +32,19 @@ documentation`_ on same.
> Quick Example
> -------------
>
> -This example demonstrates how to add two ``dpdkvhostuser`` ports to an existing
> -bridge called ``br0``::
> +This example demonstrates how to add two ``dpdkvhostuserclient`` ports to an
> +existing bridge called ``br0``::
>
> - $ ovs-vsctl add-port br0 dpdkvhostuser0 \
> - -- set Interface dpdkvhostuser0 type=dpdkvhostuser
> - $ ovs-vsctl add-port br0 dpdkvhostuser1 \
> - -- set Interface dpdkvhostuser1 type=dpdkvhostuser
> + $ ovs-vsctl add-port br0 dpdkvhostclient0 \
> + -- set Interface dpdkvhostclient0 type=dpdkvhostuserclient \
> + options:vhost-server-path=/tmp/dpdkvhostclient0
> + $ ovs-vsctl add-port br0 dpdkvhostclient1 \
> + -- set Interface dpdkvhostclient1 type=dpdkvhostuserclient \
> + options:vhost-server-path=/tmp/dpdkvhostclient1
> +
> +For the above examples to work, an appropriate server socket must be created
> +at the paths specified (``/tmp/dpdkvhostclient0`` and
> +``/tmp/dpdkvhostclient0``).
>
> vhost-user vs. vhost-user-client
> --------------------------------
> @@ -59,7 +65,8 @@ means if OVS dies, all VMs **must** be restarted. On the other hand, for
> vhost-user-client ports, OVS acts as the client and QEMU the server. This means
> OVS can die and be restarted without issue, and it is also possible to restart
> an instance itself. For this reason, vhost-user-client ports are the preferred
> -type for most use cases.
> +type for most use cases. Ports of type vhost-user are currently deprecated and
> +will be removed in a future release.
>
> type for all known use cases; the only limitation is that vhost-user client mode ports
> require QEMU version 2.7. Ports of type vhost-user are currently deprecated and
> will be removed in a future release.
Will update with this verbiage. Thanks.
> .. _dpdk-vhost-user:
>
> @@ -68,7 +75,8 @@ vhost-user
>
> .. important::
>
> - Use of vhost-user ports requires QEMU >= 2.2
> + Use of vhost-user ports requires QEMU >= 2.2; vhost-user ports are
> + *deprecated*.
>
> To use vhost-user ports, you must first add said ports to the switch. DPDK
> vhost-user ports can have arbitrary names with the exception of forward and
> diff --git a/NEWS b/NEWS
> index 82004c8..b81d033 100644
> --- a/NEWS
> +++ b/NEWS
> @@ -16,6 +16,8 @@ Post-v2.7.0
> Log level can be changed in a usual OVS way using
> 'ovs-appctl vlog' commands for 'dpdk' module. Lower bound
> still can be configured via extra arguments for DPDK EAL.
> + * dpdkvhostuser ports are marked as deprecated. They will be removed
> + in an upcoming release.
> - IPFIX now provides additional counters:
> * Total counters since metering process startup.
> * Per-flow TCP flag counters.
> diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c
> index b770b70..9ab4aeb 100644
> --- a/lib/netdev-dpdk.c
> +++ b/lib/netdev-dpdk.c
> @@ -966,6 +966,8 @@ netdev_dpdk_vhost_construct(struct netdev *netdev)
> err = vhost_common_construct(netdev);
>
> ovs_mutex_unlock(&dpdk_mutex);
> + VLOG_WARN_ONCE("dpdkvhostuser ports are considered deprecated; "
> + "please migrate to dpdkvhostuserclient ports.");
>
> I think we can:
> 1) Print the socket name and port name
> 2) I am not sure ‘_ONCE’ is required; do you really think the log will have that many instances.
My idea to not print the socket / port name is because I figure there
would be cases that users have many VMs, do an upgrade, and see the log
spewed over and over. Maybe that's a good thing though - not sure.
If you consider a deployment with 100 VMs, that means this will pop up
100 times. Even more, in deployments where they are using orchestration
software, or a cluster management solution, I figure those systems may
still be using the old style dpdkvhostuser ports, and again didn't want
to print it for every start of a VM - especially when there isn't
anything the user could do about it.
If you think there's a strong value in warning on every start, and
including the details of the port, I'll do that. I'm not married to
this particular code ;)
I was thinking more like 20 times would be the high number in most cases, but 100 is fine in rare cases.
This should be hard to ignore (maybe even a little annoying) for the
ultimate benefit of the user experience.
-Aaron
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