Re: [PATCH v13 2/3] event/dlb2: add support for independent enqueue

[Jerin Jacob <jerinjacobk@gmail.com>]

On Fri, Oct 4, 2024 at 6:34 PM Abdullah Sevincer
<abdullah.sevincer@intel.com> wrote:
>
> DLB devices need events to be enqueued in the same order they are
> dequeued. Applications are not suppose to change event order between
> dequeue and to enqueue. Since Eventdev standard does not add such
> restrictions independent enqueue support is needed for DLB PMD so that
> it restores dequeue order on enqueue if applications happen to change
> it. It also adds missing releases in places where events are dropped
> by the application and it expects implicit release to handle it.
>
> By default the feature will be off on all DLB ports and they will
> behave the same as older releases. To enable reordering feature,
> applications need to add the flag RTE_EVENT_PORT_CFG_INDEPENDENT_ENQ
> to port configuration if only the device advertises the capability
> RTE_EVENT_DEV_CAP_INDEPENDENT_ENQ.
>
> Signed-off-by: Abdullah Sevincer <abdullah.sevincer@intel.com>
> Acked-by: Mattias Rönnblom <mattias.ronnblom@ericsson.com>
> ---
>  doc/guides/prog_guide/eventdev/eventdev.rst |  33 ++
>  doc/guides/rel_notes/release_24_11.rst      |   5 +
>  drivers/event/dlb2/dlb2.c                   | 490 +++++++++++++-------
>  drivers/event/dlb2/dlb2_avx512.c            |  27 +-
>  drivers/event/dlb2/dlb2_inline_fns.h        |   8 +
>  drivers/event/dlb2/dlb2_priv.h              |  25 +-
>  drivers/event/dlb2/rte_pmd_dlb2.h           |  24 +
>  7 files changed, 422 insertions(+), 190 deletions(-)
>
> diff --git a/doc/guides/prog_guide/eventdev/eventdev.rst b/doc/guides/prog_guide/eventdev/eventdev.rst
> index fb6dfce102..dd22ab69d2 100644
> --- a/doc/guides/prog_guide/eventdev/eventdev.rst
> +++ b/doc/guides/prog_guide/eventdev/eventdev.rst
> +Independent Enqueue Capability
> +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> +
> +Some eventdev hardware devices such as DLB2 expects all forwarded events to be

Remove DLB2 from _generic+ documentation. Instead, express with capability.

> +enqueued in the same order as they are dequeued. For dropped events, their
> +releases should come at the same location as the original event was expected.
> +Hardware has this restriction as it uses the order to retrieve information about
> +the original event that was sent to the CPU. This contains information like atomic flow
> +ID to release the flow lock and ordered events sequence number to restore the
> +original order.
> +
> +Some applications, like those based on the DPDK dispatcher library, want
> +enqueue order independence. To support this, DLB2 PMD supports the

Remove DLB2 from generic documentation.

> +``RTE_EVENT_DEV_CAP_INDEPENDENT_ENQ`` capability.
> +
> +This capability applies to Eventdevs supporting burst mode. On ports where
> +the application is going to change enqueue order,
> +``RTE_EVENT_PORT_CFG_INDEPENDENT_ENQ`` support should be enabled.
> +
> +Example code to inform PMD that the application plans to use independent enqueue
> +order on a port:
> +
> +    .. code-block:: c
> +
> +       if (capability & RTE_EVENT_DEV_CAP_INDEPENDENT_ENQ)
> +         port_config = port_config | RTE_EVENT_PORT_CFG_INDEPENDENT_ENQ;
> +

--------------------
AS MENTIONED IN THE LAST comment, Please move this section to 1/3 patch.


> +This code example enables enqueue event reordering inside DLB2 PMD before the events
> +are sent to the DLB2 hardware. If the application is not going to change the enqueue
> +order, this flag should not be enabled to get better performance. DLB2 PMD saves
> +ordering information inside the impl_opaque field of the event, and this field should
> +be preserved for all FORWARD or RELEASE events.

This section is a candidate for DLB2 specific documentation. DONT ADD IN
doc/guides/prog_guide/eventdev/eventdev.rst instead move any DLB2
specific documentation
DLB2 specific document if needed.


> +
>  Stopping the EventDev
>  ~~~~~~~~~~~~~~~~~~~~~
>
> diff --git a/doc/guides/rel_notes/release_24_11.rst b/doc/guides/rel_notes/release_24_11.rst
> index dee6723b70..98e9732100 100644
> --- a/doc/guides/rel_notes/release_24_11.rst
> +++ b/doc/guides/rel_notes/release_24_11.rst
> @@ -72,6 +72,11 @@ New Features
>    * Added support for independent enqueue feature. Updated Event Device and
>      PMD feature list.
>
> +  * Updated DLB2 driver for independent enqueue feature. Applications should
> +    use ``RTE_EVENT_PORT_CFG_INDEPENDENT_ENQ`` to enable the feature if the
> +    capability  ``RTE_EVENT_DEV_CAP_INDEPENDENT_ENQ`` exists.

Starting from “Applications ...” is not specific to DLB2, remove from
release notes.

Please send the next version on Monday, planning to submit rc1 PR on Tuesday.