RE: [RFC PATCH] eventdev: adapter API to configure multiple Rx queues

["Naga Harish K, S V" <s.v.naga.harish.k@intel.com>]

> -----Original Message-----
> From: Shijith Thotton <sthotton@marvell.com>
> Sent: Monday, January 13, 2025 5:36 PM
> To: Shijith Thotton <sthotton@marvell.com>; Naga Harish K, S V
> <s.v.naga.harish.k@intel.com>; dev@dpdk.org
> Cc: Pavan Nikhilesh Bhagavatula <pbhagavatula@marvell.com>; Pathak,
> Pravin <pravin.pathak@intel.com>; Hemant Agrawal
> <hemant.agrawal@nxp.com>; Sachin Saxena <sachin.saxena@nxp.com>;
> Mattias R_nnblom <mattias.ronnblom@ericsson.com>; Jerin Jacob
> <jerinj@marvell.com>; Liang Ma <liangma@liangbit.com>; Mccarthy, Peter
> <peter.mccarthy@intel.com>; Van Haaren, Harry
> <harry.van.haaren@intel.com>; Carrillo, Erik G <erik.g.carrillo@intel.com>;
> Gujjar, Abhinandan S <abhinandan.gujjar@intel.com>; Amit Prakash Shukla
> <amitprakashs@marvell.com>; Burakov, Anatoly
> <anatoly.burakov@intel.com>
> Subject: RE: [RFC PATCH] eventdev: adapter API to configure multiple Rx
> queues
> 
> Hi @Naga Harish K, S V,
> 
> >>> This RFC introduces a new API,
> >>> rte_event_eth_rx_adapter_queues_add(),
> >>> designed to enhance the flexibility of configuring multiple Rx
> >>> queues in eventdev Rx adapter.
> >>>
> >>> The existing rte_event_eth_rx_adapter_queue_add() API supports
> >>> adding multiple queues by specifying rx_queue_id = -1, but it lacks
> >>> the ability to
> >apply
> >>> specific configurations to each of the added queues.
> >>>
> >>
> >>The application can still use the existing
> >>rte_event_eth_rx_adapter_queue_add() API in a loop with different
> >>configurations for different queues.
> >>
> >>The proposed API is not enabling new features that cannot be achieved
> >>with the existing API.
> >>Adding new APIs without much usefulness causes unnecessary
> >>complexity/confusion for users.
> >>
> >
> >The new API was introduced because the existing API does not support
> >adding multiple queues with specific configurations. It serves as a
> >burst variant of the existing API, like many other APIs in DPDK.
> >

The other burst APIs may be there for dataplane functionalities, but may not be for the control plane functionalities.

> >For better clarity, the API can be renamed to
> >rte_event_eth_rx_adapter_queue_add_burst() if needed.
> >
> >In hardware, adding each queue individually incurs significant
> >overheads, such as mailbox operations. A burst API helps to amortize
> >this overhead. Since real- world applications often call the API with
> >specific queue_ids, the burst API can provide considerable benefits.
> >Testing shows a 75% reduction in time when adding multiple queues to
> >the RX adapter using the burst API on our platform.
> >

 As batching helps for a particular hardware device, this may not be applicable for all platforms/cases.
	Since queue_add is a control plane operation, latency may not be a concern.
How to specify a particular set(specific queue_ids) of rx_queues that has a non-zero start index with the new proposed API?
	Since this is still not possible with the proposed API, the existing queue_add API needs to be used with specific queue_ids and their configurations.

> >I can modify the old API implementation to act as a wrapper around the
> >burst API, with number of queues equal to 1. If concerns remain, we can
> >explore deprecation as an alternative.
> >
> 
> Please let me know if you have any suggestions/feedback on what I said
> above.

Still feel the new proposed API can be avoided as it looks like a different combination of existing API instead of adding some new features.

> If not, I can go ahead and send v1.
> 
> Thanks,
> Shijith
> 
> >>> The proposed API, rte_event_eth_rx_adapter_queues_add, addresses
> >>> this limitation by:
> >>>
> >>> - Enabling users to specify an array of rx_queue_id values alongside
> >>>   individual configurations for each queue.
> >>>
> >>> - Supporting a nb_rx_queues argument to define the number of queues to
> >>>   configure. When set to 0, the API applies a common configuration to
> >>>   all queues, similar to the existing rx_queue_id = -1 behavior.
> >>>
> >>> This enhancement allows for more granular control when configuring
> >multiple
> >>> Rx queues. Additionally, the API can act as a replacement for the
> >>> older API, offering both flexibility and improved functionality.
> >>>
> >>> Signed-off-by: Shijith Thotton <sthotton@marvell.com>
> >>> ---
> >>>  lib/eventdev/eventdev_pmd.h             | 34
> +++++++++++++++++++++++++
> >>>  lib/eventdev/rte_event_eth_rx_adapter.h | 34
> >>> +++++++++++++++++++++++++
> >>>  2 files changed, 68 insertions(+)
> >>>
> >>> diff --git a/lib/eventdev/eventdev_pmd.h
> >>> b/lib/eventdev/eventdev_pmd.h index 36148f8d86..2e458a9779
> 100644
> >>> --- a/lib/eventdev/eventdev_pmd.h
> >>> +++ b/lib/eventdev/eventdev_pmd.h
> >>> @@ -25,6 +25,7 @@
> >>>  #include <rte_mbuf_dyn.h>
> >>>
> >>>  #include "event_timer_adapter_pmd.h"
> >>> +#include "rte_event_eth_rx_adapter.h"
> >>>  #include "rte_eventdev.h"
> >>>
> >>>  #ifdef __cplusplus
> >>> @@ -708,6 +709,37 @@ typedef int
> >>> (*eventdev_eth_rx_adapter_queue_add_t)(
> >>>  		int32_t rx_queue_id,
> >>>  		const struct rte_event_eth_rx_adapter_queue_conf
> >>> *queue_conf);
> >>>
> >>> +/**
> >>> + * Add ethernet Rx queues to event device. This callback is invoked
> >>> +if
> >>> + * the caps returned from rte_eventdev_eth_rx_adapter_caps_get(,
> >>> +eth_port_id)
> >>> + * has RTE_EVENT_ETH_RX_ADAPTER_CAP_INTERNAL_PORT set.
> >>> + *
> >>> + * @param dev
> >>> + *   Event device pointer
> >>> + *
> >>> + * @param eth_dev
> >>> + *   Ethernet device pointer
> >>> + *
> >>> + * @param rx_queue_id
> >>> + *   Ethernet device receive queue index array
> >>> + *
> >>> + * @param queue_conf
> >>> + *   Additional configuration structure array
> >>> + *
> >>> + * @param nb_rx_queues
> >>> + *   Number of ethernet device receive queues
> >>> + *
> >>> + * @return
> >>> + *   - 0: Success, ethernet receive queues added successfully.
> >>> + *   - <0: Error code returned by the driver function.
> >>> + */
> >>> +typedef int (*eventdev_eth_rx_adapter_queues_add_t)(
> >>> +		const struct rte_eventdev *dev,
> >>> +		const struct rte_eth_dev *eth_dev,
> >>> +		int32_t rx_queue_id[],
> >>> +		const struct rte_event_eth_rx_adapter_queue_conf
> >>> queue_conf[],
> >>> +		uint16_t nb_rx_queues);
> >>> +
> >>>  /**
> >>>   * Delete ethernet Rx queues from event device. This callback is invoked if
> >>>   * the caps returned from eventdev_eth_rx_adapter_caps_get(,
> >eth_port_id)
> >>> @@ -1578,6 +1610,8 @@ struct eventdev_ops {
> >>>  	/**< Get ethernet Rx adapter capabilities */
> >>>  	eventdev_eth_rx_adapter_queue_add_t eth_rx_adapter_queue_add;
> >>>  	/**< Add Rx queues to ethernet Rx adapter */
> >>> +	eventdev_eth_rx_adapter_queues_add_t
> >>> eth_rx_adapter_queues_add;
> >>> +	/**< Add Rx queues to ethernet Rx adapter */
> >>>  	eventdev_eth_rx_adapter_queue_del_t eth_rx_adapter_queue_del;
> >>>  	/**< Delete Rx queues from ethernet Rx adapter */
> >>>  	eventdev_eth_rx_adapter_queue_conf_get_t
> >>> eth_rx_adapter_queue_conf_get; diff --git
> >>> a/lib/eventdev/rte_event_eth_rx_adapter.h
> >>> b/lib/eventdev/rte_event_eth_rx_adapter.h
> >>> index 9237e198a7..9a5c560b67 100644
> >>> --- a/lib/eventdev/rte_event_eth_rx_adapter.h
> >>> +++ b/lib/eventdev/rte_event_eth_rx_adapter.h
> >>> @@ -553,6 +553,40 @@ int
> rte_event_eth_rx_adapter_queue_add(uint8_t
> >>> id,
> >>>  			int32_t rx_queue_id,
> >>>  			const struct rte_event_eth_rx_adapter_queue_conf
> >>> *conf);
> >>>
> >>> +/**
> >>> + * Add multiple receive queues to an event adapter.
> >>> + *
> >>> + * @param id
> >>> + *  Adapter identifier.
> >>> + *
> >>> + * @param eth_dev_id
> >>> + *  Port identifier of Ethernet device.
> >>> + *
> >>> + * @param rx_queue_id
> >>> + *  Array of Ethernet device receive queue indices.
> >>> + *  If nb_rx_queues is 0, then rx_queue_id is ignored.
> >>> + *
> >>> + * @param conf
> >>> + *  Array of additional configuration structures of type
> >>> + *  *rte_event_eth_rx_adapter_queue_conf*. conf[i] is used for
> >>> rx_queue_id[i].
> >>> + *  If nb_rx_queues is 0, then conf[0] is used for all Rx queues.
> >>> + *
> >>> + * @param nb_rx_queues
> >>> + *  Number of receive queues to add.
> >>> + *  If nb_rx_queues is 0, then all Rx queues configured for
> >>> + *  the device are added with the same configuration in conf[0].
> >>> + * @see RTE_EVENT_ETH_RX_ADAPTER_CAP_MULTI_EVENTQ
> >>> + *
> >>> + * @return
> >>> + *  - 0: Success, Receive queues added correctly.
> >>> + *  - <0: Error code on failure.
> >>> + */
> >>> +__rte_experimental
> >>> +int rte_event_eth_rx_adapter_queues_add(
> >>> +			uint8_t id, uint16_t eth_dev_id, int32_t
> >>> rx_queue_id[],
> >>> +			const struct rte_event_eth_rx_adapter_queue_conf
> >>> conf[],
> >>> +			uint16_t nb_rx_queues);
> >>> +
> >>>  /**
> >>>   * Delete receive queue from an event adapter.
> >>>   *
> >>> --
> >>> 2.25.1