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

[Pavan Nikhilesh Bhagavatula <pbhagavatula@marvell.com>]

>-----Original Message-----
>From: Andrew Rybchenko <arybchenko@solarflare.com>
>Sent: Friday, August 16, 2019 1:53 PM
>To: Pavan Nikhilesh Bhagavatula <pbhagavatula@marvell.com>; Jerin
>Jacob Kollanukkaran <jerinj@marvell.com>; ferruh.yigit@intel.com;
>John McNamara <john.mcnamara@intel.com>; Marko Kovacevic
><marko.kovacevic@intel.com>; Thomas Monjalon
><thomas@monjalon.net>
>Cc: dev@dpdk.org
>Subject: [EXT] Re: [dpdk-dev] [PATCH 1/7] ethdev: add set ptype
>function
>
>External Email
>
>----------------------------------------------------------------------
>The patch should add item in release notes (as well as all other
>subsequent patches which add more features).

Will update release notes in v2.
>
>On 8/16/19 8:55 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)` and PMD
>> will set rte_mbuf::packet_type to 0.
>
>As I understand PMD may provide more reach classification
>than set. So, it is not obliged to set packet type to 0.

Yes it would be undefined. 
>
>> -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)`.
>>
>> Suggested-by: Konstantin Ananyev <konstantin.ananyev@intel.com>
>> Signed-off-by: Pavan Nikhilesh <pbhagavatula@marvell.com>
>> ---
>>   doc/guides/nics/features.rst        | 12 ++++++++----
>>   lib/librte_ethdev/rte_ethdev.c      | 28
>++++++++++++++++++++++++++++
>>   lib/librte_ethdev/rte_ethdev.h      | 17 +++++++++++++++++
>>   lib/librte_ethdev/rte_ethdev_core.h |  6 ++++++
>>   4 files changed, 59 insertions(+), 4 deletions(-)
>>
>> diff --git a/doc/guides/nics/features.rst
>b/doc/guides/nics/features.rst
>> index c4e128d2f..d4d55f721 100644
>> --- a/doc/guides/nics/features.rst
>> +++ b/doc/guides/nics/features.rst
>> @@ -582,10 +582,14 @@ Supports inner packet L4 checksum.
>>   Packet type parsing
>>   -------------------
>>
>> -Supports packet type parsing and returns a list of supported types.
>> -
>> -* **[implements] eth_dev_ops**: ``dev_supported_ptypes_get``.
>> -* **[related]    API**: ``rte_eth_dev_get_supported_ptypes()``.
>> +Supports packet type parsing and returns a list of supported types.
>Allows
>> +application to set ptypes it is interested in.
>> +
>> +* **[implements] eth_dev_ops**: ``dev_supported_ptypes_get``,
>> +  ``dev_supported_ptypes_set``.
>> +* **[related]    API**: ``rte_eth_dev_get_supported_ptypes()``,
>> +  ``rte_eth_dev_set_supported_ptypes()``.
>> +* **[provides]   mbuf**: ``mbuf.packet_type``.
>>
>>
>>   .. _nic_features_timesync:
>> diff --git a/lib/librte_ethdev/rte_ethdev.c
>b/lib/librte_ethdev/rte_ethdev.c
>> index 17d183e1f..72fe660c3 100644
>> --- a/lib/librte_ethdev/rte_ethdev.c
>> +++ b/lib/librte_ethdev/rte_ethdev.c
>> @@ -2602,6 +2602,34 @@
>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)
>> +{
>> +	int i;
>> +	struct rte_eth_dev *dev;
>> +	const uint32_t *all_ptypes;
>> +	uint32_t all_ptype_mask = 0;
>> +
>> +	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_set,
>> +				-ENOTSUP);
>> +	RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops-
>>dev_supported_ptypes_get,
>> +				-ENOTSUP);
>> +	all_ptypes = (*dev->dev_ops-
>>dev_supported_ptypes_get)(dev);
>> +
>> +	if (!all_ptypes)
>
>If I remember correctly DPDK style prefers to compare vs 0.
>
>> +		return -ENOTSUP;
>> +
>> +	for (i = 0; all_ptypes[i] != RTE_PTYPE_UNKNOWN; ++i)
>> +		all_ptype_mask |= all_ptypes[i];
>> +
>> +	if ((all_ptype_mask & ptype_mask) != ptype_mask)
>> +		return -ENOTSUP;
>
>Do we really want so strict check here? May be just check
>that intersection is not empty if ptype_mask is not empty?
>
I was thinking the same maybe we can return the successfully set mask?  
And the application can use software parser to parse the rest?.

>I think that setting ptype_mask to 0 could be pretty often and
>may be it makes sense to avoid get in the case.

Agreed.

>Also consider
>to return OK even if there is no get/set callbacks at all.

I think if we are ok with the above approach i.e. returning successfully set ptypes, 
we will return 0 if there are no supported get/set call backs and the application 
can softparse the ptypes.

>
>> +
>> +	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 dc6596bc9..f97f0a6e5 100644
>> --- a/lib/librte_ethdev/rte_ethdev.h
>> +++ b/lib/librte_ethdev/rte_ethdev.h
>> @@ -2431,6 +2431,23 @@ 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);
>> +/**
>> + * Request Ethernet device to set only specific packet types in the
>packet.
>> + *
>> + * 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.
>> + * @return
>> + *   - (0) Successfully set supported ptypes.
>> + *   - (-ENODEV) if *port_id* is invalid.
>> + *   - (-ENOTSUP) Packet type mask supplied is not supported by the
>Ethernet
>> + *		  device.
>> + */
>> +int rte_eth_dev_set_supported_ptypes(uint16_t port_id, uint32_t
>ptype_mask);
>
>Should it be experimental?
>
>Please, add it to .map file.

Will fix in v2.
>
>>   /**
>>    * 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..02ee7c12c 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 int (*eth_dev_supported_ptypes_set_t)(struct
>rte_eth_dev *dev,
>> +					      uint32_t ptype_mask);
>> +/**< @internal Set required ptypes of an Ethernet device. */
>> +
>>   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 the interested ptypes. */
>>
>>   	vlan_filter_set_t          vlan_filter_set; /**< Filter VLAN Setup. */
>>   	vlan_tpid_set_t            vlan_tpid_set; /**< Outer/Inner VLAN
>TPID Setup. */
>> --
>> 2.22.0
>>