Re: [PATCH v2 1/1] ethdev: support congestion management

[Jerin Jacob <jerinjacobk@gmail.com>]

On Wed, Sep 28, 2022 at 1:50 PM Andrew Rybchenko
<andrew.rybchenko@oktetlabs.ru> wrote:
>
> Cc David. See some kind of reincarnation of RTE_FUNC_PTR_*
> macro below.
>

> > +
> > +/**
> > + * @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
> > +      * http://www.aciri.org/floyd/papers/red/red.html
> > +      * @see struct rte_cman_red_params
> > +      */
> > +     RTE_CMAN_RED = RTE_BIT64(0),
>
> I believe enums with 64-bit values are bad.

No strong opinion. Will change to 32bit.

> > --- /dev/null
> > +++ b/lib/ethdev/rte_cman.c
> > @@ -0,0 +1,101 @@
> > +/* SPDX-License-Identifier: BSD-3-Clause
> > + * Copyright(C) 2022 Marvell International Ltd.
> > + */
> > +
> > +#include <stdint.h>
> > +
> > +#include <rte_errno.h>
> > +#include "rte_ethdev.h"
> > +#include "ethdev_driver.h"
> > +
> > +static int
> > +eth_err(uint16_t port_id, int ret)
> > +{
> > +     if (ret == 0)
> > +             return 0;
> > +
> > +     if (rte_eth_dev_is_removed(port_id))
> > +             return -EIO;
> > +
> > +     return ret;
> > +}
>
> It is a dup from rte_ethdev.c. I think it should be moved to some
> internal header.

Ack.


>
> > +
> > +#define RTE_CMAN_FUNC_ERR_RET(func)                                  \
>
> There is nothing CMAN specific in the function except location.
>
> Cc David who deprecated similar macros in the release cycle,
> but this one have a log message.

Yes. It has an additional log function. No strong opinion
Will remove this macro.

>
> > +do {                                                                 \
> > +     if (func == NULL) {                                             \
> > +             RTE_ETHDEV_LOG(ERR, "Function not implemented\n");      \
> > +             return -ENOTSUP;                                        \
> > +     }                                                               \
> > +} while (0)
> > +
> > +/* Get congestion management information for a port */
> > +int
> > +rte_eth_cman_info_get(uint16_t port_id, struct rte_eth_cman_info *info)
> > +{
> > +     struct rte_eth_dev *dev;
> > +
> > +     RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -ENODEV);
> > +     dev = &rte_eth_devices[port_id];
> > +
> > +     if (info == NULL) {
> > +             RTE_ETHDEV_LOG(ERR, "congestion management info is NULL\n");
> > +             return -EINVAL;
> > +     }
> > +
> > +     RTE_CMAN_FUNC_ERR_RET(dev->dev_ops->cman_info_get);
>
> I think we should memset(&info, 0, sizeof(*info)) here since
> all drivers must do it anyway.

Will do.

>
> > +     return eth_err(port_id, (*dev->dev_ops->cman_info_get)(dev, info));
> > +}
> > +
> > +/* Initialize congestion management structure with default values */
> > +int
> > +rte_eth_cman_config_init(uint16_t port_id, struct rte_eth_cman_config *config)
> > +{
> > +     struct rte_eth_dev *dev;
> > +
> > +     RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -ENODEV);
> > +     dev = &rte_eth_devices[port_id];
> > +
> > +     if (config == NULL) {
> > +             RTE_ETHDEV_LOG(ERR, "congestion management config is NULL\n");
> > +             return -EINVAL;
> > +     }
> > +
> > +     RTE_CMAN_FUNC_ERR_RET(dev->dev_ops->cman_config_init);
> > +     return eth_err(port_id, (*dev->dev_ops->cman_config_init)(dev, config));
> > +}
> > +
> > +/* Configure congestion management on a port */
> > +int
> > +rte_eth_cman_config_set(uint16_t port_id, struct rte_eth_cman_config *config)
> > +{
> > +     struct rte_eth_dev *dev;
> > +
> > +     RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -ENODEV);
> > +     dev = &rte_eth_devices[port_id];
> > +
> > +     if (config == NULL) {
> > +             RTE_ETHDEV_LOG(ERR, "congestion management config is NULL\n");
> > +             return -EINVAL;
> > +     }
> > +
> > +     RTE_CMAN_FUNC_ERR_RET(dev->dev_ops->cman_config_set);
> > +     return eth_err(port_id, (*dev->dev_ops->cman_config_set)(dev, config));
> > +}
> > +
> > +/* Retrieve congestion management configuration of a port */
> > +int
> > +rte_eth_cman_config_get(uint16_t port_id, struct rte_eth_cman_config *config)
> > +{
> > +     struct rte_eth_dev *dev;
> > +
> > +     RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -ENODEV);
> > +     dev = &rte_eth_devices[port_id];
> > +
> > +     if (config == NULL) {
> > +             RTE_ETHDEV_LOG(ERR, "congestion management config is NULL\n");
> > +             return -EINVAL;
> > +     }
> > +
> > +     RTE_CMAN_FUNC_ERR_RET(dev->dev_ops->cman_config_get);
>
> memset(&config, 0, sizeof(*config));

Ack

>
> > +     return eth_err(port_id, (*dev->dev_ops->cman_config_get)(dev, config));
> > +}
> > diff --git a/lib/ethdev/rte_ethdev.h b/lib/ethdev/rte_ethdev.h
> > index de9e970d4d..f4bb644c6a 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>
> > @@ -5506,6 +5507,156 @@ 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),
>
> Do we really want one more enum with 64-bit initialized member?
> IMHO, it should be either defines or 32-bit.

Will keep it 32 bit.

>
> > +};
> > +
> > +/**
> > + * @warning
> > + * @b EXPERIMENTAL: this structure 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 */
>
> I think we should highlight that it is set to zeros on get
> right now.

Will change as "Reserved for future fields. Always return as zero when
rte_eth_cman_config_get() invoked"


>
> > +     uint8_t rsvd[8];
> > +};
> > +
> > +/**
> > + * @warning
> > + * @b EXPERIMENTAL: this structure 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 */
>
> Must be zeros on get and set right now.

Will change as "Reserved for future fields. Must be set to zero on get
and set operation "

>
> > +             uint8_t rsvd_obj_params[4];
> > +     } 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[4];
>
> same here.

Ack

> > +     } mode_param;
> > +};
> > +
>
> [snip]
>
> > +/**
> > + * @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);
>
> Just a niot, but may be config should be 'const'?

Yes. We can keep as const.

>
> [snip]