Re: [dpdk-dev] [PATCH v4 1/7] ethdev: add set ptype function

[Andrew Rybchenko <arybchenko@solarflare.com>]

On 10/1/19 9:34 AM, pbhagavatula@marvell.com wrote:
> From: Pavan Nikhilesh <pbhagavatula@marvell.com>
>
> Add `rte_eth_dev_set_supported_ptypes` function that will allow the
> application to inform the PMD the packet types it is interested in.
> Based on the ptypes set PMDs can optimize their Rx path.
>
> -If application doesn’t want any ptype information it can call
> `rte_eth_dev_set_supported_ptypes(ethdev_id, RTE_PTYPE_UNKNOWN, NULL, 0)`
> and PMD may skip packet type processing and set rte_mbuf::packet_type to
> RTE_PTYPE_UNKNOWN.
>
> -If application doesn’t call `rte_eth_dev_set_supported_ptypes` PMD can
> return `rte_mbuf::packet_type` with `rte_eth_dev_get_supported_ptypes`.
>
> -If application is interested only in L2/L3 layer, it can inform the PMD
> to update `rte_mbuf::packet_type` with L2/L3 ptype by calling
> `rte_eth_dev_set_supported_ptypes(ethdev_id,
> 		RTE_PTYPE_L2_MASK | RTE_PTYPE_L3_MASK, NULL, 0)`.
>
> Suggested-by: Konstantin Ananyev <konstantin.ananyev@intel.com>
> Signed-off-by: Pavan Nikhilesh <pbhagavatula@marvell.com>



> diff --git a/doc/guides/rel_notes/release_19_11.rst b/doc/guides/rel_notes/release_19_11.rst
> index 27cfbd9e3..7e31b9401 100644
> --- a/doc/guides/rel_notes/release_19_11.rst
> +++ b/doc/guides/rel_notes/release_19_11.rst
> @@ -56,6 +56,13 @@ New Features
>        Also, make sure to start the actual text at the margin.
>        =========================================================
>   
> +* **Added ethdev API to set supported packet types**
> +
> +  *  Added new API ``rte_eth_dev_set_supported_ptypes`` that allows an
> +     application to inform PMD about packet types classification the application
> +     is interested in
> +  *  This scheme will allow PMDs to avoid lookup to internal ptype table on Rx
> +     and thereby improve Rx performance if application wishes do so.

Extra empty line is required here in accordance with documentation 
guidelines.

>   Removed Items
>   -------------
> diff --git a/lib/librte_ethdev/rte_ethdev.c b/lib/librte_ethdev/rte_ethdev.c
> index 17d183e1f..061de7ac5 100644
> --- a/lib/librte_ethdev/rte_ethdev.c
> +++ b/lib/librte_ethdev/rte_ethdev.c
> @@ -2602,6 +2602,44 @@ rte_eth_dev_get_supported_ptypes(uint16_t port_id, uint32_t ptype_mask,
>   	return j;
>   }
>   
> +int
> +rte_eth_dev_set_supported_ptypes(uint16_t port_id, uint32_t ptype_mask,
> +				 uint32_t *set_ptypes, int num)

May be num should be unsigned int?

> +{
> +	int i, j;
> +	struct rte_eth_dev *dev;
> +	const uint32_t *all_ptypes;
> +
> +	RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -ENODEV);
> +	dev = &rte_eth_devices[port_id];
> +	RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->dev_supported_ptypes_get, 0);
> +	RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->dev_supported_ptypes_set, 0);

if (num > 0 && set_ptypes == NULL)
     return -EINVAL;

> +
> +	if (ptype_mask == 0)

if (num > 0)
      set_ptypes[0] = RTE_PTYPE_UNKNOWN;

> +		return (*dev->dev_ops->dev_supported_ptypes_set)(dev,
> +				ptype_mask);
> +
> +	all_ptypes = (*dev->dev_ops->dev_supported_ptypes_get)(dev);
> +	if (all_ptypes == NULL)

if (num > 0)
      set_ptypes[0] = RTE_PTYPE_UNKNOWN;

> +		return 0;
> +
> +	for (i = 0, j = 0; set_ptypes && (all_ptypes[i] != RTE_PTYPE_UNKNOWN);

set_ptypes != NULL in accordance with coding guidelines

> +									++i) {

Please, consider to put condition check and increment in its own lines.
IMHO, above it a bit hard to read.

> +		if (ptype_mask & all_ptypes[i]) {

Should it be done if all_ptypes[i] have some bits out of ptype_mask?
Should set_ptypes have bits out of ptype_mask when set below?

> +			if (j < num - 1) {
> +				set_ptypes[j] = all_ptypes[i];
> +				j++;
> +				continue;
> +			}
> +			break;

Do we need an indication if provided set_ptype is not enough
to return all ptypes? I think it should be explained/highlighted
in the function description with explanation why.

> +		}
> +	}
> +
> +	set_ptypes[j] = RTE_PTYPE_UNKNOWN;

I think we should allow set_ptypes == NULL if num == 0.
So, it should be set here if not NULL only.

> +
> +	return (*dev->dev_ops->dev_supported_ptypes_set)(dev, ptype_mask);
> +}
> +
>   void
>   rte_eth_macaddr_get(uint16_t port_id, struct rte_ether_addr *mac_addr)
>   {
> diff --git a/lib/librte_ethdev/rte_ethdev.h b/lib/librte_ethdev/rte_ethdev.h
> index d9871782e..6c5fd789a 100644
> --- a/lib/librte_ethdev/rte_ethdev.h
> +++ b/lib/librte_ethdev/rte_ethdev.h
> @@ -2431,6 +2431,35 @@ int rte_eth_dev_fw_version_get(uint16_t port_id,
>    */
>   int rte_eth_dev_get_supported_ptypes(uint16_t port_id, uint32_t ptype_mask,
>   				     uint32_t *ptypes, int num);
> +/**
> + * @warning
> + * @b EXPERIMENTAL: this API may change without prior notice.
> + *
> + * Inform Ethernet device of the packet types classification in which
> + * the recipient is interested.
> + *
> + * Application can use this function to set only specific ptypes that it's
> + * interested. This information can be used by the PMD to optimize Rx path.
> + *
> + * @param port_id
> + *   The port identifier of the Ethernet device.
> + * @param ptype_mask
> + *   The ptype family that application is interested in.
> + * @param set_ptypes
> + *   An array pointer to store set packet types, allocated by caller. The
> + *   function marks the end of array with RTE_PTYPE_UNKNOWN.
> + * @param num
> + *   Size of the array pointed by param ptypes.
> + *   Should be rte_eth_dev_get_supported_ptypes() + 1 to accomodate the
> + *   set ptypes.
> + * @return
> + *   - (0) if Success.
> + *   - (-ENODEV) if *port_id* invalid.
> + *   - (-EINVAL) if *ptype_mask* is invalid.

or set_ptype is NULL when num is greater than zero.

> + */
> +__rte_experimental
> +int rte_eth_dev_set_supported_ptypes(uint16_t port_id, uint32_t ptype_mask,
> +				     uint32_t *set_ptypes, int num);
>   
>   /**
>    * Retrieve the MTU of an Ethernet device.
> diff --git a/lib/librte_ethdev/rte_ethdev_core.h b/lib/librte_ethdev/rte_ethdev_core.h
> index 2922d5b7c..93bc34480 100644
> --- a/lib/librte_ethdev/rte_ethdev_core.h
> +++ b/lib/librte_ethdev/rte_ethdev_core.h
> @@ -110,6 +110,10 @@ typedef void (*eth_dev_infos_get_t)(struct rte_eth_dev *dev,
>   typedef const uint32_t *(*eth_dev_supported_ptypes_get_t)(struct rte_eth_dev *dev);
>   /**< @internal Get supported ptypes of an Ethernet device. */
>   
> +typedef uint32_t (*eth_dev_supported_ptypes_set_t)(struct rte_eth_dev *dev,
> +					      uint32_t ptype_mask);
> +/**< @internal Inform device about packet types in which the recipient is interested. */
> +
>   typedef int (*eth_queue_start_t)(struct rte_eth_dev *dev,
>   				    uint16_t queue_id);
>   /**< @internal Start rx and tx of a queue of an Ethernet device. */
> @@ -421,6 +425,8 @@ struct eth_dev_ops {
>   	eth_fw_version_get_t       fw_version_get; /**< Get firmware version. */
>   	eth_dev_supported_ptypes_get_t dev_supported_ptypes_get;
>   	/**< Get packet types supported and identified by device. */
> +	eth_dev_supported_ptypes_set_t dev_supported_ptypes_set;
> +	/**< Inform device about packet types in which the recipient is interested. */
>   
>   	vlan_filter_set_t          vlan_filter_set; /**< Filter VLAN Setup. */
>   	vlan_tpid_set_t            vlan_tpid_set; /**< Outer/Inner VLAN TPID Setup. */
> diff --git a/lib/librte_ethdev/rte_ethdev_version.map b/lib/librte_ethdev/rte_ethdev_version.map
> index 6df42a47b..e14745b9c 100644
> --- a/lib/librte_ethdev/rte_ethdev_version.map
> +++ b/lib/librte_ethdev/rte_ethdev_version.map
> @@ -283,4 +283,7 @@ EXPERIMENTAL {
>   
>   	# added in 19.08
>   	rte_eth_read_clock;
> +
> +	# added in 19.11
> +	rte_eth_dev_set_supported_ptypes;
>   };