Re: [dpdk-dev] [RFC PATCH] ethdev: support congestion management

[Ajit Khaparde <ajit.khaparde@broadcom.com>]

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On Mon, May 30, 2022 at 6:16 AM <jerinj@marvell.com> wrote:
>
> From: Jerin Jacob <jerinj@marvell.com>
>
> NIC HW controllers often come with congestion management support on
> various HW objects such as Rx queue depth or mempool queue depth.
>
> Also, it can support various modes of operation such as RED
> (Random early discard), WRED etc on those HW objects.
>
> This patch adds a framework to express such modes(enum rte_cman_mode)
> and introduce (enum rte_eth_cman_obj) to enumerate the different
> objects where the modes can operate on.
>
> This patch adds RTE_CMAN_RED mode of operation and
> RTE_ETH_CMAN_OBJ_RX_QUEUE, RTE_ETH_CMAN_OBJ_RX_QUEUE_MEMPOOL object.
>
> Introduced reserved fields in configuration structure
> backed by rte_eth_cman_config_init() to add new configuration
> parameters without ABI breakage.
>
> Added rte_eth_cman_info_get() API to get the information such as
> supported modes and objects.
>
> Added rte_eth_cman_config_init(), rte_eth_cman_config_set() APIs
> to configure congestion management on those object with associated mode.
>
> Finally, Added rte_eth_cman_config_get() API to retrieve the
> applied configuration.

Can you also add How all this helps an application? Thanks

>
>
> Signed-off-by: Jerin Jacob <jerinj@marvell.com>
> ---
>  doc/guides/nics/features.rst         |  12 +++
>  doc/guides/nics/features/default.ini |   1 +
>  lib/eal/include/meson.build          |   1 +
>  lib/eal/include/rte_cman.h           |  51 ++++++++++
>  lib/ethdev/rte_ethdev.h              | 145 +++++++++++++++++++++++++++
>  5 files changed, 210 insertions(+)
>  create mode 100644 lib/eal/include/rte_cman.h
>
> diff --git a/doc/guides/nics/features.rst b/doc/guides/nics/features.rst
> index 21bedb743f..ffcc2bcc92 100644
> --- a/doc/guides/nics/features.rst
> +++ b/doc/guides/nics/features.rst
> @@ -727,6 +727,18 @@ Supports configuring per-queue stat counter mapping.
>    ``rte_eth_dev_set_tx_queue_stats_mapping()``.
>
>
> +.. _nic_features_congestion_management
> +
> +Congestion management
> +---------------------
> +
> +Supports congestion management.
> +
> +* **[implements] eth_dev_ops**: ``cman_info_get``, ``cman_config_set``, ``cman_config_get``.
> +* **[related]    API**: ``rte_eth_cman_info_get()``, ``rte_eth_cman_config_init()``,
> +  ``rte_eth_cman_config_set()``, ``rte_eth_cman_config_get()``.
> +
> +
>  .. _nic_features_fw_version:
>
>  FW version
> diff --git a/doc/guides/nics/features/default.ini b/doc/guides/nics/features/default.ini
> index b1d18ac62c..060497e41f 100644
> --- a/doc/guides/nics/features/default.ini
> +++ b/doc/guides/nics/features/default.ini
> @@ -60,6 +60,7 @@ Tx descriptor status =
>  Basic stats          =
>  Extended stats       =
>  Stats per queue      =
> +Congestion management =
>  FW version           =
>  EEPROM dump          =
>  Module EEPROM dump   =
> diff --git a/lib/eal/include/meson.build b/lib/eal/include/meson.build
> index 9700494816..40e31e0e6d 100644
> --- a/lib/eal/include/meson.build
> +++ b/lib/eal/include/meson.build
> @@ -10,6 +10,7 @@ headers += files(
>          'rte_branch_prediction.h',
>          'rte_bus.h',
>          'rte_class.h',
> +        'rte_cman.h',
>          'rte_common.h',
>          'rte_compat.h',
>          'rte_debug.h',
> diff --git a/lib/eal/include/rte_cman.h b/lib/eal/include/rte_cman.h
> new file mode 100644
> index 0000000000..e6dad2ebf7
> --- /dev/null
> +++ b/lib/eal/include/rte_cman.h
> @@ -0,0 +1,51 @@
> +/* SPDX-License-Identifier: BSD-3-Clause
> + * Copyright(C) 2022 Marvell International Ltd.
> + */
> +
> +#ifndef RTE_CMAN_H
> +#define RTE_CMAN_H
> +
> +#ifdef __cplusplus
> +extern "C" {
> +#endif
> +
> +#include <rte_bitops.h>
> +
> +/**
> + * @file
> + * Congestion management related parameters for DPDK.
> + */
> +
> +/** Congestion management modes */
> +enum rte_cman_mode {
> +       /** Congestion based on Random Early Detection.
> +        *
> +        * https://en.wikipedia.org/wiki/Random_early_detection
> +        * @see struct rte_cman_red_params
> +        */
> +       RTE_CMAN_RED = RTE_BIT64(0),
> +};
> +
> +/**
> + * RED based congestion management configuration parameters.
> + */
> +struct rte_cman_red_params {
> +       /**< Minimum threshold (min_th) value
> +        *
> +        * Value expressed as percentage. Value must be in 0 to 100(inclusive).
> +        */
> +       uint8_t min_th;
> +       /**< Maximum threshold (max_th) value
> +        *
> +        * Value expressed as percentage. Value must be in 0 to 100(inclusive).
> +        */
> +       uint8_t max_th;
> +       /** Inverse of packet marking probability maximum value (maxp = 1 / maxp_inv) */
> +       uint16_t maxp_inv;
> +};
> +
> +#ifdef __cplusplus
> +}
> +#endif
> +
> +#endif /* RTE_CMAN_H */
> diff --git a/lib/ethdev/rte_ethdev.h b/lib/ethdev/rte_ethdev.h
> index 04cff8ee10..7c8718bb2e 100644
> --- a/lib/ethdev/rte_ethdev.h
> +++ b/lib/ethdev/rte_ethdev.h
> @@ -160,6 +160,7 @@ extern "C" {
>  #define RTE_ETHDEV_DEBUG_TX
>  #endif
>
> +#include <rte_cman.h>
>  #include <rte_compat.h>
>  #include <rte_log.h>
>  #include <rte_interrupts.h>
> @@ -5452,6 +5453,150 @@ typedef struct {
>  __rte_experimental
>  int rte_eth_dev_priv_dump(uint16_t port_id, FILE *file);
>
> +/* Congestion management */
> +
> +/** Enumerate list of ethdev congestion management objects */
> +enum rte_eth_cman_obj {
> +       /** Congestion management based on Rx queue depth */
> +       RTE_ETH_CMAN_OBJ_RX_QUEUE = RTE_BIT64(0),
> +       /** Congestion management based on mempool depth associated with Rx queue
> +        * @see rte_eth_rx_queue_setup()
> +        */
> +       RTE_ETH_CMAN_OBJ_RX_QUEUE_MEMPOOL = RTE_BIT64(1),
> +};
> +
> +/**
> + * @warning
> + * @b EXPERIMENTAL: this API may change, or be removed, without prior notice
> + *
> + * A structure used to retrieve information of ethdev congestion management.
> + */
> +struct rte_eth_cman_info {
> +       /** Set of supported congestion management modes
> +        * @see enum rte_cman_mode
> +        */
> +       uint64_t modes_supported;
> +       /** Set of supported congestion management objects
> +        * @see enum rte_eth_cman_obj
> +        */
> +       uint64_t objs_supported;
> +       /** Reserved for future fields */
> +       uint8_t rsvd[64];
> +};
> +
> +/**
> + * @warning
> + * @b EXPERIMENTAL: this API may change, or be removed, without prior notice
> + *
> + * A structure used to configure the ethdev congestion management.
> + */
> +struct rte_eth_cman_config {
> +       /** Congestion management object */
> +       enum rte_eth_cman_obj obj;
> +       /** Congestion management mode */
> +       enum rte_cman_mode mode;
> +       union {
> +               /** Rx queue to configure congestion management.
> +                *
> +                * Valid when object is RTE_ETH_CMAN_OBJ_RX_QUEUE or
> +                * RTE_ETH_CMAN_OBJ_RX_QUEUE_MEMPOOL.
> +                */
> +               uint16_t rx_queue;
> +               /** Reserved for future fields */
> +               uint8_t rsvd_obj_params[16];
> +       } obj_param;
> +       union {
> +               /** RED configuration parameters.
> +                *
> +                * Valid when mode is RTE_CMAN_RED.
> +                */
> +               struct rte_cman_red_params red;
> +               /** Reserved for future fields */
> +               uint8_t rsvd_mode_params[64];
> +       } mode_param;
> +};
> +
> +/**
> + * @warning
> + * @b EXPERIMENTAL: this API may change, or be removed, without prior notice
> + *
> + * Retrieve the information for ethdev congestion management
> + *
> + * @param port_id
> + *   The port identifier of the Ethernet device.
> + * @param info
> + *   A pointer to a structure of type *rte_eth_cman_info* to be filled with
> + *   the information about congestion management.
> + * @return
> + *   - (0) if successful.
> + *   - (-ENOTSUP) if support for cman_info_get does not exist.
> + *   - (-ENODEV) if *port_id* invalid.
> + *   - (-EINVAL) if bad parameter.
> + */
> +__rte_experimental
> +int rte_eth_cman_info_get(uint16_t port_id, struct rte_eth_cman_info *info);
> +
> +/**
> + * @warning
> + * @b EXPERIMENTAL: this API may change, or be removed, without prior notice
> + *
> + * Initialize the ethdev congestion management configuration structure with default values.
> + *
> + * @param port_id
> + *   The port identifier of the Ethernet device.
> + * @param config
> + *   A pointer to a structure of type *rte_eth_cman_config* to be initialized
> + *   with default value.
> + * @return
> + *   - (0) if successful.
> + *   - (-ENODEV) if *port_id* invalid.
> + *   - (-EINVAL) if bad parameter.
> + */
> +__rte_experimental
> +int rte_eth_cman_config_init(uint16_t port_id, struct rte_eth_cman_config *config);
> +
> +/**
> + * @warning
> + * @b EXPERIMENTAL: this API may change, or be removed, without prior notice
> + *
> + * Configure ethdev congestion management
> + *
> + * @param port_id
> + *   The port identifier of the Ethernet device.
> + * @param config
> + *   A pointer to a structure of type *rte_eth_cman_config* to be configured.
> + * @return
> + *   - (0) if successful.
> + *   - (-ENOTSUP) if support for cman_config_set does not exist.
> + *   - (-ENODEV) if *port_id* invalid.
> + *   - (-EINVAL) if bad parameter.
> + */
> +__rte_experimental
> +int rte_eth_cman_config_set(uint16_t port_id, struct rte_eth_cman_config *config);
> +
> +/**
> + * @warning
> + * @b EXPERIMENTAL: this API may change, or be removed, without prior notice
> + *
> + * Retrieve the applied ethdev congestion management parameters for the given port.
> + *
> + * @param port_id
> + *   The port identifier of the Ethernet device.
> + * @param config
> + *   A pointer to a structure of type *rte_eth_cman_config* to retrieve
> + *   congestion management parameters for the given object.
> + *   Application must fill all parameters except mode_param parameter in
> + *   struct rte_eth_cman_config.
> + *
> + * @return
> + *   - (0) if successful.
> + *   - (-ENOTSUP) if support for cman_config_get does not exist.
> + *   - (-ENODEV) if *port_id* invalid.
> + *   - (-EINVAL) if bad parameter.
> + */
> +__rte_experimental
> +int rte_eth_cman_config_get(uint16_t port_id, struct rte_eth_cman_config *config);
> +
>  #include <rte_ethdev_core.h>
>
>  /**
> --
> 2.36.1
>

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