Re: [dpdk-dev] [PATCH 10/10] eventdev: include DSW event device documentation

[Jerin Jacob <jerin.jacob@caviumnetworks.com>]

-----Original Message-----
> Date: Mon, 10 Sep 2018 14:59:51 +0200
> From: Mattias Rönnblom <mattias.ronnblom@ericsson.com>
> To: jerin.jacob@caviumnetworks.com
> CC: bruce.richardson@intel.com, dev@dpdk.org
> Subject: Re: [dpdk-dev] [PATCH 10/10] eventdev: include DSW event device
>  documentation
> User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101
>  Thunderbird/52.9.1
> 
> 
> Will DSW be included in 18.11?

Yes.

I may have minor comments on individual patches. But overall the patches looks
good.

Please fix the following check-git-log.sh issues

[dpdk-next-eventdev] $ ./devtools/check-git-log.sh 
Wrong headline prefix:
	eventdev: add DSW device and queue configuration
	eventdev: add DSW port configuration
	eventdev: add support in DSW for linking/unlinking ports
	eventdev: add DSW event scheduling and device start/stop
	eventdev: add DSW port load measurements
	eventdev: add load balancing to the DSW event device
	eventdev: let DSW event device sort events on dequeue
	eventdev: implement eventdev 'xstats' counters in DSW

> 
> /M
> 
> On 2018-08-30 16:27, Mattias Rönnblom wrote:
> > The DSW event device is documented in DPDK Programmer's Guide.
> > 
> > Signed-off-by: Mattias Rönnblom <mattias.ronnblom@ericsson.com>
> > ---
> >   doc/guides/eventdevs/dsw.rst   | 97 ++++++++++++++++++++++++++++++++++
> >   doc/guides/eventdevs/index.rst |  1 +
> >   2 files changed, 98 insertions(+)
> >   create mode 100644 doc/guides/eventdevs/dsw.rst
> > 
> > diff --git a/doc/guides/eventdevs/dsw.rst b/doc/guides/eventdevs/dsw.rst
> > new file mode 100644
> > index 000000000..de41ae9d3
> > --- /dev/null
> > +++ b/doc/guides/eventdevs/dsw.rst
> > @@ -0,0 +1,97 @@
> > +..  SPDX-License-Identifier: BSD-3-Clause
> > +    Copyright(c) 2017 Intel Corporation.
> > +    Copyright(c) 2018 Ericsson AB
> > +
> > +Distributed Software Eventdev Poll Mode Driver
> > +==============================================
> > +
> > +The distributed software eventdev is a parallel implementation of the
> > +eventdev API, which distributes the task of scheduling events among
> > +all the eventdev ports and the lcore threads using them.
> > +
> > +Features
> > +--------
> > +
> > +Queues
> > + * Atomic
> > + * Parallel
> > + * Single-Link
> > +
> > +Ports
> > + * Load balanced (for Atomic, Ordered, Parallel queues)
> > + * Single Link (for single-link queues)
> > +
> > +Configuration and Options
> > +-------------------------
> > +
> > +The distributed software eventdev is a vdev device, and as such can be
> > +created from the application code, or from the EAL command line:
> > +
> > +* Call ``rte_vdev_init("event_dsw0")`` from the application
> > +
> > +* Use ``--vdev="event_dsw0"`` in the EAL options, which will call
> > +  rte_vdev_init() internally
> > +
> > +Example:
> > +
> > +.. code-block:: console
> > +
> > +    ./your_eventdev_application --vdev="event_dsw0"
> > +
> > +Limitations
> > +-----------
> > +
> > +Unattended Ports
> > +~~~~~~~~~~~~~~~~
> > +
> > +The distributed software eventdev uses an internal signaling schema
> > +between the ports to achieve load balancing. In order for this to
> > +work, the application must perform enqueue and/or dequeue operations
> > +on all ports.
> > +
> > +Producer-only ports which currently have no events to enqueue should
> > +periodically call rte_event_enqueue_burst() with a zero-sized burst.
> > +
> > +Ports left unattended for longer periods of time will prevent load
> > +balancing, and also cause traffic interruptions on the flows which
> > +are in the process of being migrated.
> > +
> > +Output Buffering
> > +~~~~~~~~~~~~~~~~
> > +
> > +For efficiency reasons, the distributed software eventdev might not
> > +send enqueued events immediately to the destination port, but instead
> > +store them in an internal buffer in the source port.
> > +
> > +In case no more events are enqueued on a port with buffered events,
> > +these events will be sent after the application has performed a number
> > +of enqueue and/or dequeue operations.
> > +
> > +For explicit flushing, an application may call
> > +rte_event_enqueue_burst() with a zero-sized burst.
> > +
> > +
> > +Priorities
> > +~~~~~~~~~~
> > +
> > +The distributed software eventdev does not support event priorities.
> > +
> > +Ordered Queues
> > +~~~~~~~~~~~~~~
> > +
> > +The distributed software eventdev does not support the ordered queue type.
> > +
> > +
> > +"All Types" Queues
> > +~~~~~~~~~~~~~~~~~~
> > +
> > +The distributed software eventdev does not support queues of type
> > +RTE_EVENT_QUEUE_CFG_ALL_TYPES, which allow both atomic, ordered, and
> > +parallel events on the same queue.
> > +
> > +Dynamic Link/Unlink
> > +~~~~~~~~~~~~~~~~~~~
> > +
> > +The distributed software eventdev does not support calls to
> > +rte_event_port_link() or rte_event_port_unlink() after
> > +rte_event_dev_start() has been called.
> > diff --git a/doc/guides/eventdevs/index.rst b/doc/guides/eventdevs/index.rst
> > index 18ec8e462..984eea5f4 100644
> > --- a/doc/guides/eventdevs/index.rst
> > +++ b/doc/guides/eventdevs/index.rst
> > @@ -14,5 +14,6 @@ application trough the eventdev API.
> >       dpaa
> >       dpaa2
> >       sw
> > +    dsw
> >       octeontx
> >       opdl
> >