[PATCH v4 1/2] ethdev: add query_update sync and async function calls

[Gregory Etelson]

Hello Thomas,

[]

> > Current API allows either query or update indirect flow action.
> > If port hardware allows both update and query in a single operation,
> > application still has to issue 2 separate hardware requests.
> >
> > The patch adds `rte_flow_action_handle_query_update` function call,
> > and it's async version `rte_flow_async_action_handle_query_update`
> > to atomically query and update flow action.
> 
> What is the benefit?
> Is it a performance optimization? How much?
>

rte_flow_action_handle_query_update() can query data and conditionally update it in a single HW operation.
That provides accuracy that cannot be achieved with existing API.
For example, quota flow action must be updated when it in the PASS state only. 
If application use existing query, by the time it gets query data and analyzes it, HW object state can change.
As the result application update action will not reflect HW configuration.

The function can provide general optimization, but that was not tested.
 
> > int
> > rte_flow_action_handle_query_update
> >        (uint16_t port_id, struct rte_flow_action_handle *handle,
> >         const void *update, void *query,
> >         enum rte_flow_query_update_mode mode,
> >         struct rte_flow_error *error);
> >
> > int
> > rte_flow_async_action_handle_query_update
> >        (uint16_t port_id, uint32_t queue_id,
> >         const struct rte_flow_op_attr *op_attr,
> >         struct rte_flow_action_handle *action_handle,
> >         const void *update, void *query,
> >         enum rte_flow_query_update_mode mode,
> >         void *user_data, struct rte_flow_error *error);
> 
> No need to copy the functions in the commit log.
> 

Will be updated in v5

> > Application can control query and update order, if that is supported
> > by port hardware, by setting qu_mode parameter to
> > RTE_FLOW_QU_QUERY_FIRST or RTE_FLOW_QU_UPDATE_FIRST.
> >
> > RTE_FLOW_QU_QUERY and RTE_FLOW_QU_UPDATE parameter values
> provide
> > query only and update only functionality for backward compatibility
> > with existing API.
> 
> Why do we need such compatibility?
> The existing functions will stay, isn't it?
> 

rte_flow_action_handle_query_update() has extended functionality with better HW support.
The plan is to deprecate and replace existing query and update functions.

> [...]
> > + * RTE_FLOW_QU_QUERY_FIRST
> > + *   Force port to query action before update.
> > + * RTE_FLOW_QU_UPDATE_FIRST
> > + *   Force port to update action before update.
> 
> You mean "before query".
> Anyway you don't need to repeat the enum in the comment.
> 

Correct, must be "before query".
Will fix in v5.

> > + *
> > + * @see rte_flow_action_handle_query_update()
> > + * @see rte_flow_async_action_handle_query_update()
> > + */
> > +enum rte_flow_query_update_mode {
> > +     RTE_FLOW_QU_QUERY_FIRST,  /* query before update */
> > +     RTE_FLOW_QU_UPDATE_FIRST, /* query after  update */
> > +};
> > +
> > +/**
> > + * @warning
> > + * @b EXPERIMENTAL: this API may change without prior notice.
> > + *
> > + * Query and/or update indirect flow action.
> > + * If update parameter is NULL the function queries indirect action.
> > + * If query parameter is NULL the function updates indirect action.
> > + * If both query and update not NULL, the function atomically
> > + * queries and updates indirect action. Query and update carried in
> order
> 
> "are" carried?
> 

Typo. Will fix in v5.

> > + * specified in the mode parameter.
> > + *
> > + * @param port_id
> > + *   Port identifier of Ethernet device.
> > + * @param handle
> > + *   Handle for the indirect action object to be updated.
> > + * @param update
> > + *   Update profile specification used to modify the action pointed by
> handle.
> > + *   *update* could be with the same type of the immediate action
> corresponding
> 
> could be "of" the same type
> 

Will fix in v5.

> > + *   to the *handle* argument when creating, or a wrapper structure
> includes
> > + *   action configuration to be updated and bit fields to indicate the
> member
> > + *   of fields inside the action to update.
> > + * @param query
> > + *   Pointer to storage for the associated query data type.
> > + * @param mode
> > + *   Operational mode.
> > + * @param error
> > + *   Perform verbose error reporting if not NULL.
> > + *   PMDs initialize this structure in case of error only.
> > + *
> > + * @return
> > + * 0 on success, a negative errno value otherwise and rte_errno is set.
> > + * - (ENOTSUP) if underlying device does not support this functionality.
> > + * - (EINVAL) - if *handle* invalid
> > + */
> > +__rte_experimental
> > +int
> > +rte_flow_action_handle_query_update(uint16_t port_id,
> > +                                 struct rte_flow_action_handle *handle,
> > +                                 const void *update, void *query,
> > +                                 enum rte_flow_query_update_mode mode,
> > +                                 struct rte_flow_error *error);
> > +
> > +/**
> > + * @warning
> > + * @b EXPERIMENTAL: this API may change without prior notice.
> > + *
> > + * Enqueue async indirect flow action query and/or update
> > + *
> > + * @param port_id
> > + *   Port identifier of Ethernet device.
> > + * @param queue_id
> > + *   Flow queue which is used to update the rule.
> > + * @param attr
> > + *   Indirect action update operation attributes.
> > + * @param handle
> > + *   Handle for the indirect action object to be updated.
> > + * @param update
> > + *   Update profile specification used to modify the action pointed by
> handle.
> > + *   *update* could be with the same type of the immediate action
> corresponding
> > + *   to the *handle* argument when creating, or a wrapper structure
> includes
> 
> includes -> including
> 

Will fix in v5.

> > + *   action configuration to be updated and bit fields to indicate the
> member
> > + *   of fields inside the action to update.
> 
> Where can we find how such wrapper should look like?
>

That patch will be sent later.
I'll rephrase.
 
> > + * @param query
> > + *   Pointer to storage for the associated query data type.
> > + *   Query result returned on async completion event.
> > + * @param mode
> > + *   Operational mode.
> > + * @param user_data
> > + *   The user data that will be returned on async completion event.
> > + * @param error
> > + *   Perform verbose error reporting if not NULL.
> > + *   PMDs initialize this structure in case of error only.
> > + *
> > + * @return
> > + *   0 on success, a negative errno value otherwise and rte_errno is set.
> > + * - (ENOTSUP) if underlying device does not support this functionality.
> > + * - (EINVAL) - if *handle* invalid
> > + */
> > +__rte_experimental
> > +int
> > +rte_flow_async_action_handle_query_update(uint16_t port_id, uint32_t
> queue_id,
> > +                                       const struct rte_flow_op_attr *attr,
> > +                                       struct rte_flow_action_handle *handle,
> > +                                       const void *update, void *query,
> > +                                       enum rte_flow_query_update_mode mode,
> > +                                       void *user_data,
> > +                                       struct rte_flow_error *error);
> 
> > --- a/lib/ethdev/version.map
> > +++ b/lib/ethdev/version.map
> > @@ -298,6 +298,11 @@ EXPERIMENTAL {
> >       rte_flow_get_q_aged_flows;
> >       rte_mtr_meter_policy_get;
> >       rte_mtr_meter_profile_get;
> > +
> > +     # future
> 
> It should be "# added in 23.03"
> 

Will fix in v5.

> > +     rte_flow_action_handle_query_update;
> > +     rte_flow_async_action_handle_query_update;
> 
>