Re: [PATCH v5 0/6] Introduce event pre-scheduling

[Stephen Hemminger <stephen@networkplumber.org>]

On Fri, 4 Oct 2024 21:54:45 +0530
<pbhagavatula@marvell.com> wrote:

> From: Pavan Nikhilesh <pbhagavatula@marvell.com>
> 
> Event pre-scheduling improves scheduling performance by assigning events
> to event ports in advance when dequeues are issued.
> This series introduces various types and levels of pre-scheduling to the
> eventdev library.
> 
> pre-scheduling Types:
>  * RTE_EVENT_PRESCHEDULE_NONE: No pre-scheduling.
>  * RTE_EVENT_PRESCHEDULE: Always issue a pre-schedule when dequeue is issued.
>  * RTE_EVENT_PRESCHEDULE_ADAPTIVE: Delay issuing pre-schedule until there
>    are no forward progress constraints with the held flow contexts.
> 
> pre-scheduling Levels:
>  * Event Device Level Pre-scheduling: Pre-scheduling can be enabled or disabled at the
>    event device during configuration. Event devices can indicate pre-scheduling
>    capabilities using `RTE_EVENT_DEV_CAP_EVENT_PRESCHEDULE` and
>   `RTE_EVENT_DEV_CAP_EVENT_PRESCHEDULE_ADAPTIVE` via the event device info
>   function `info.event_dev_cap`.
>  * Event Port Level Prefetch: Pre-scheduling can be selectively enabled or disabled
>    at the event port during runtime. Event devices can indicate this capability
>    using `RTE_EVENT_PORT_CAP_PER_PORT_PRESCHEDULE` via the event device info
>    function `info.event_port_cap`.
>  * Application Controlled Prefetch Hint: Applications can provide hints to the
>    event device to start pre-scheduling events using the new API
>    `rte_event_port_pre-schedule`. Event devices can indicate this capabilities using
>    `RTE_EVENT_DEV_CAP_PRESCHEDULE_EXPLICIT` via the event device info function
>    `info.event_dev_cap`.
> 
> The rte_event_dequeue_burst operation initiates the pre-schedule operation, which
> completes in parallel without affecting the flow context of the dequeued events and
> dequeue latency. On the next dequeue operation, the pre-scheduleed events are
> dequeued, and pre-schedule operation is initiated again.
> 
> In the case of application-controlled pre-schedule hints, the currently held flow
> contexts, if any, are not affected by the pre-schedule operation. On the next
> dequeue operation, the pre-scheduleed events are returned, but pre-schedule is not
> initiated again until the application provides the hint again. If pre-scheduling
> is already enabled at the event device level or event port level, the hint is ignored.
> 
> v2 Changes:
> - s/prefetch/pre-schedule (Mattias).
> v3 Changes:
> - Add CNXK preschedule implementation.
> - Update test-eventdev to use prescheduling.
> - Update examples to use prescheduling.
> v4 Changes:
> - Fix compilation.
> v5 Changes:
> - Update ABI changes
> - s/RTE_EVENT_DEV_PRESCHEDULE/RTE_EVENT_PRESCHEDULE/
> - s/RTE_EVENT_DEV_CAP_SW_PRESCHEDULE/RTE_EVENT_DEV_CAP_PRESCHEDULE_EXPLICIT/
> - s/RTE_EVENT_PORT_CAP_EVENT_PER_PORT_PRESCHEDULE/RTE_EVENT_PORT_CAP_PER_PORT_PRESCHEDULE
> - Various documentation fixes and updates.
> 
> 
> Pavan Nikhilesh (6):
>   eventdev: introduce event pre-scheduling
>   eventdev: add event port pre-schedule modify
>   eventdev: add event preschedule hint
>   event/cnkx: add pre-schedule support
>   app/test-eventdev: add pre-scheduling support
>   examples: use eventdev pre-scheduling
> 
>  app/test-eventdev/evt_common.h                |  45 +++--
>  app/test-eventdev/evt_options.c               |  17 ++
>  app/test-eventdev/evt_options.h               |   1 +
>  app/test/test_eventdev.c                      | 143 ++++++++++++++++
>  doc/guides/eventdevs/cnxk.rst                 |  10 --
>  doc/guides/eventdevs/features/cnxk.ini        |   1 +
>  doc/guides/eventdevs/features/default.ini     |   1 +
>  doc/guides/prog_guide/eventdev/eventdev.rst   |  48 ++++++
>  doc/guides/rel_notes/release_24_11.rst        |  13 ++
>  doc/guides/tools/testeventdev.rst             |   6 +
>  drivers/event/cnxk/cn10k_eventdev.c           |  19 ++-
>  drivers/event/cnxk/cn10k_worker.c             |  21 +++
>  drivers/event/cnxk/cn10k_worker.h             |   2 +
>  drivers/event/cnxk/cnxk_eventdev.c            |   2 -
>  drivers/event/cnxk/cnxk_eventdev.h            |   1 -
>  .../pipeline_worker_generic.c                 |   6 +
>  .../eventdev_pipeline/pipeline_worker_tx.c    |   6 +
>  examples/ipsec-secgw/event_helper.c           |   6 +
>  examples/l2fwd-event/l2fwd_event_generic.c    |   6 +
>  .../l2fwd-event/l2fwd_event_internal_port.c   |   6 +
>  examples/l3fwd/l3fwd_event_generic.c          |   6 +
>  examples/l3fwd/l3fwd_event_internal_port.c    |   6 +
>  lib/eventdev/eventdev_pmd.h                   |   4 +
>  lib/eventdev/eventdev_private.c               |  41 ++++-
>  lib/eventdev/eventdev_trace_points.c          |   6 +
>  lib/eventdev/rte_eventdev.h                   | 159 ++++++++++++++++++
>  lib/eventdev/rte_eventdev_core.h              |  14 +-
>  lib/eventdev/rte_eventdev_trace_fp.h          |  19 ++-
>  lib/eventdev/version.map                      |   6 +
>  29 files changed, 592 insertions(+), 29 deletions(-)

Looks good, but the new API's should be experimental right?