Re: [dpdk-dev] [PATCH v2 1/7] ethdev: add set ptype function

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

>On 8/21/19 11:47 PM, 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.
>
>I would say that "... and PMD may skip packet type processing and just
>set
>rte_mbuf::packet_type to RTE_PTYPE_UNKNOWN."
>
>I.e. PMD is not obligated to skip packet type processing, it just has
>permission to do it.
>
>> -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 ++++++---
>>   doc/guides/rel_notes/release_19_11.rst   |  7 ++++++
>>   lib/librte_ethdev/rte_ethdev.c           | 32
>++++++++++++++++++++++++
>>   lib/librte_ethdev/rte_ethdev.h           | 16 ++++++++++++
>>   lib/librte_ethdev/rte_ethdev_core.h      |  6 +++++
>>   lib/librte_ethdev/rte_ethdev_version.map |  3 +++
>>   6 files changed, 72 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.
>
>It is better to start new sentence from new line. It will keep the first
>line
>untouched.

Ack.

>
>> +
>> +* **[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/doc/guides/rel_notes/release_19_11.rst
>b/doc/guides/rel_notes/release_19_11.rst
>> index 8490d897c..a7cec1fe8 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 API in ethdev to set supported packet types**
>
>May I suggest:
>Added ethdev API to set supported packet types.

Ack.
>
>> +
>> +  *  Added new API ``rte_eth_dev_set_supported_ptypes`` that
>allows an
>> +     application to request PMD to set specific ptypes defined
>> +     through ``rte_eth_dev_set_supported_ptypes`` in
>``rte_mbuf::packet_type``.
>
>Consider:
>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.
>

Ack.

>> +  *  This scheme will allow PMDs to avoid lookup to internal ptype
>table on Rx
>> +     and thereby improve Rx performance if application wishes do so.
>>
>>   Removed Items
>>   -------------
>> diff --git a/lib/librte_ethdev/rte_ethdev.c
>b/lib/librte_ethdev/rte_ethdev.c
>> index 17d183e1f..f529cbe9f 100644
>> --- a/lib/librte_ethdev/rte_ethdev.c
>> +++ b/lib/librte_ethdev/rte_ethdev.c
>> @@ -2602,6 +2602,38 @@
>rte_eth_dev_get_supported_ptypes(uint16_t port_id, uint32_t
>ptype_mask,
>>   	return j;
>>   }
>>
>> +uint32_t
>> +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;
>> +	uint32_t supp_ptype_mask = 0;
>> +
>> +	RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -ENODEV);
>
>We should either return 0 or change prototype to return successfully
>set ptypes in optional (may be NULL) output parameter.
>I would change the prototype.

Ack. I will change the prototype.

>
>> +	dev = &rte_eth_devices[port_id];
>> +	RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops-
>>dev_supported_ptypes_get, 0);
>
>Since API is not mandatory and provides just hits for optimizations, I
>think
>it should return error in really unexpected cases only. It looks like
>invalid
>port_id is the only case.

Ack.

>
>> +	if (ptype_mask == 0) {
>> +		RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops-
>>dev_supported_ptypes_set,
>> +					0);
>> +		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)
>> +		return 0;
>> +
>> +	for (i = 0; all_ptypes[i] != RTE_PTYPE_UNKNOWN; ++i)
>> +		all_ptype_mask |= all_ptypes[i];
>> +
>> +	supp_ptype_mask = all_ptype_mask & ptype_mask;
>
>I think it is not that useful to do here. Moreover, it is invalid in a
>way how
>it is implemented right now. E.g. if get returns:
>RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV4 | RTE_PTYPE_L4_TCP
>RTE_PTYPE_L2_ETHER | RTE_PTYPE_L3_IPV4 | RTE_PTYPE_L4_UDP
>RTE_PTYPE_L2_ARP
>and mask is RTE_PTYPE_L2_MASK | RTE_PTYPE_L3_MASK |
>RTE_PTYPE_L4_MASK
>the result will be:
>RTE_PTYPE_L2_ARP | RTE_PTYPE_L3_IPV4 | RTE_PTYPE_L4_FRAG
>

Ack. I will change the check.

>
>> +	return (*dev->dev_ops->dev_supported_ptypes_set)(dev,
>supp_ptype_mask);
>
>It is not checked that  dev_supported_ptypes_set is not NULL.
>
>> +}
>> +
>>   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..1ab0af4d8 100644
>> --- a/lib/librte_ethdev/rte_ethdev.h
>> +++ b/lib/librte_ethdev/rte_ethdev.h
>> @@ -2431,6 +2431,22 @@ 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);
>> +/**
>
>Missing:
>  * @warning
>  * @b EXPERIMENTAL: this API may change without prior notice.
>
>> + * Request Ethernet device to set only specific packet types in the
>packet.
>
>Request sounds mandatory. Consider:
>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.
>
>It should be highligted that for each layer it should be either
>full mask (e.g. RTE_PTYPE_L4_MASK) or only one specific type
>(e.g. RTE_PTYPE_L4_TCP) since otherwise caller may try
>RTE_PTYPE_L4_TCP|RTE_PTYPE_L4_UDP which is RTE_PTYPE_L4_FRAG
>in fact.
>
>> + * @return
>> + *   - (>=0) Ptype mask that has been set successfully.
>
>uint32_t is always >=0, so I think (>=0) should be removed.
>However, in fact I think it should be:
>Negative errno value on error, 0 on success.
>
>I think that "Ptype mask that has been set successfully" could be
>misleading since for each layer it is not a bit mark, but enum.
>The output should be supported_ptype_get-slyle. I.e. an array
>which is terminated by RTE_PTYPE_UNKNOWN entry.
>

I will make it ptype_get-style with mask in place.

>> + */
>> +__rte_experimental
>> +uint32_t rte_eth_dev_set_supported_ptypes(uint16_t port_id,
>> +					  uint32_t ptype_mask);
>>
>>   /**
>>    * 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..e65ae983d 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 Set required ptypes of an Ethernet device. */
>
>Consider:
>Inform device about packet types in which the recipient is interested.

Ack.

>
>> +
>>   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. */
>
>Consider
>Inform device about packet types in which the recipient is interested.

Ack.

>
>>
>>   	vlan_filter_set_t          vlan_filter_set; /**< Filter VLAN Setup. */
>>   	vlan_tpid_set_t            vlan_tpid_set; /**< Outer/Inner VLAN
>TPID Setup. */
>
><snip>