31. ABI and API Deprecation

See the guidelines document for details of the ABI policy. API and ABI deprecation notices are to be posted here.

31.1. Deprecation Notices

  • kvargs: The function rte_kvargs_process will get a new parameter for returning key match count. It will ease handling of no-match case.
  • eal: The function rte_eal_remote_launch will return new error codes after read or write error on the pipe, instead of calling rte_panic.
  • rte_atomicNN_xxx: These APIs do not take memory order parameter. This does not allow for writing optimized code for all the CPU architectures supported in DPDK. DPDK has adopted the atomic operations from https://gcc.gnu.org/onlinedocs/gcc/_005f_005fatomic-Builtins.html. These operations must be used for patches that need to be merged in 20.08 onwards. This change will not introduce any performance degradation.
  • rte_smp_*mb: These APIs provide full barrier functionality. However, many use cases do not require full barriers. To support such use cases, DPDK has adopted atomic operations from https://gcc.gnu.org/onlinedocs/gcc/_005f_005fatomic-Builtins.html. These operations and a new wrapper rte_atomic_thread_fence instead of __atomic_thread_fence must be used for patches that need to be merged in 20.08 onwards. This change will not introduce any performance degradation.
  • mempool: Helper macro MEMPOOL_HEADER_SIZE() is deprecated and will be removed in DPDK 22.11. The replacement macro RTE_MEMPOOL_HEADER_SIZE() is internal only.
  • mempool: Macro to register mempool driver MEMPOOL_REGISTER_OPS() is deprecated and will be removed in DPDK 22.11. Use replacement macro RTE_MEMPOOL_REGISTER_OPS().
  • mempool: The mempool API macros MEMPOOL_PG_* are deprecated and will be removed in DPDK 22.11.
  • bus: The rte_bus object will be made opaque in DPDK 22.11. The goal is to remove it from the public ABI and make this object extendable. As a side effect, registering a bus will be marked as an internal API: external users may still register their bus using a new driver header (see enable_driver_sdk meson option).
  • drivers: As a follow-up of the work on the rte_bus object, the rte_driver and rte_device objects (and as a domino effect, their bus-specific counterparts) will be made opaque in DPDK 22.11. Registering a driver on a bus will be marked as an internal API: external users may still register their drivers using the bus-specific driver header (see enable_driver_sdk meson option).
  • bus: The dev->device.numa_node field is set by each bus driver for every device it manages to indicate on which NUMA node this device lies. When this information is unknown, the assigned value is not consistent across the bus drivers. In DPDK 22.11, the default value will be set to -1 by all bus drivers when the NUMA information is unavailable.
  • kni: The KNI kernel module and library are not recommended for use by new applications - other technologies such as virtio-user are recommended instead. Following the DPDK technical board decision and refinement:
    • Some deprecation warnings will be added in DPDK 22.11.
    • The KNI example application will be removed from DPDK 22.11.
    • The KNI kernel module, library and PMD will be removed from the DPDK 23.11.
  • lib: will fix extending some enum/define breaking the ABI. There are multiple samples in DPDK that enum/define terminated with a .*MAX.* value which is used by iterators, and arrays holding these values are sized with this .*MAX.* value. So extending this enum/define increases the .*MAX.* value which increases the size of the array and depending on how/where the array is used this may break the ABI. RTE_ETH_FLOW_MAX is one sample of the mentioned case, adding a new flow type will break the ABI because of flex_mask[RTE_ETH_FLOW_MAX] array usage in following public struct hierarchy: rte_eth_fdir_flex_conf -> rte_eth_fdir_conf -> rte_eth_conf (in the middle). Need to identify this kind of usages and fix in 20.11, otherwise this blocks us extending existing enum/define. One solution can be using a fixed size array instead of .*MAX.* value.
  • ethdev: The function rte_eth_set_queue_rate_limit takes rate in Mbps. The queue rate is limited to 64 Gbps because declared as uint16_t. The rate parameter will be modified to uint32_t in DPDK 22.11 so that it can work for more than 64 Gbps.
  • ethdev: Since no single PMD supports RTE_ETH_RX_OFFLOAD_HEADER_SPLIT offload and the split_hdr_size field in structure rte_eth_rxmode to enable per-port header split, they will be removed in DPDK 22.11. The per-queue Rx packet split offload RTE_ETH_RX_OFFLOAD_BUFFER_SPLIT can still be used, and it is configured by rte_eth_rxseg_split.
  • ethdev: The flow director API, including rte_eth_conf.fdir_conf field, and the related structures (rte_fdir_* and rte_eth_fdir_*), will be removed in DPDK 20.11.
  • ethdev: Announce moving from dedicated modify function for each field, to using the general rte_flow_modify_field action.
  • ethdev: The flow API matching pattern structures, struct rte_flow_item_*, should start with relevant protocol header. Some matching pattern structures implements this by duplicating protocol header fields in the struct. To clarify the intention and to be sure protocol header is intact, will replace those fields with relevant protocol header struct. In v21.02 both individual protocol header fields and the protocol header struct will be added as union, target is switch usage to the protocol header by time. In v21.11 LTS, protocol header fields will be cleaned and only protocol header struct will remain.
  • ethdev: Queue specific stats fields will be removed from struct rte_eth_stats. Mentioned fields are: q_ipackets, q_opackets, q_ibytes, q_obytes, q_errors. Instead queue stats will be received via xstats API. Current method support will be limited to maximum 256 queues. Also compile time flag RTE_ETHDEV_QUEUE_STAT_CNTRS will be removed.
  • ethdev: Items and actions PF, VF, PHY_PORT, PORT_ID are deprecated as hard-to-use / ambiguous and will be removed in DPDK 22.11.
  • ethdev: The use of attributes ingress / egress in “transfer” flows is deprecated as ambiguous with respect to the embedded switch. The use of these attributes will become invalid starting from DPDK 22.11.
  • ethdev: Actions OF_SET_MPLS_TTL, OF_DEC_MPLS_TTL, OF_SET_NW_TTL, OF_COPY_TTL_OUT, OF_COPY_TTL_IN are deprecated as not supported by any PMD, so they will be removed in DPDK 22.11.
  • ethdev: Actions OF_DEC_NW_TTL, SET_IPV4_SRC, SET_IPV4_DST, SET_IPV6_SRC, SET_IPV6_DST, SET_TP_SRC, SET_TP_DST, DEC_TTL, SET_TTL, SET_MAC_SRC, SET_MAC_DST, INC_TCP_SEQ, DEC_TCP_SEQ, INC_TCP_ACK, DEC_TCP_ACK, SET_IPV4_DSCP, SET_IPV6_DSCP, SET_TAG, SET_META are marked as legacy and superseded by the generic MODIFY_FIELD action. The legacy actions should be deprecated in 22.07, once MODIFY_FIELD alternative is implemented. The legacy actions should be removed in DPDK 22.11.
  • ethdev: The enum rte_eth_event_ipsec_subtype will be extended to add new subtype values RTE_ETH_EVENT_IPSEC_SA_PKT_EXPIRY, RTE_ETH_EVENT_IPSEC_SA_BYTE_HARD_EXPIRY and RTE_ETH_EVENT_IPSEC_SA_PKT_HARD_EXPIRY in DPDK 22.11.
  • bbdev: RTE_BBDEV_OP_TYPE_COUNT terminating the rte_bbdev_op_type enum will be deprecated and instead use fixed array size when required to allow for future enum extension. Will extend API to support new operation type RTE_BBDEV_OP_FFT as per this RFC. New members will be added in rte_bbdev_driver_info to expose PMD queue topology inspired by this RFC. New member will be added in rte_bbdev_driver_info to expose the device status as per this RFC. This should be updated in DPDK 22.11.
  • cryptodev: Hide structures rte_cryptodev_sym_session and rte_cryptodev_asym_session to remove unnecessary indirection between session and the private data of session. An opaque pointer can be exposed directly to application which can be attached to the rte_crypto_op.
  • cryptodev: The function rte_cryptodev_cb_fn will be updated to have another parameter qp_id to return the queue pair ID which got error interrupt to the application, so that application can reset that particular queue pair.
  • security: Hide structure rte_security_session and expose an opaque pointer for the private data to the application which can be attached to the packet while enqueuing.
  • security: MACsec support is planned to be added in DPDK 22.11, which would result in updates to structures rte_security_macsec_xform, rte_security_macsec_stats and security capability structure rte_security_capability to accommodate MACsec capabilities.
  • eventdev: The function rte_event_crypto_adapter_queue_pair_add will accept configuration of type rte_event_crypto_adapter_queue_conf instead of rte_event, similar to rte_event_eth_rx_adapter_queue_add signature. Event will be one of the configuration fields, together with additional vector parameters.
  • eventdev: The structure rte_event_timer_adapter_stats will be extended by adding a new field evtim_drop_count. This counter will represent the number of times an event_timer expiry event is dropped by the timer adapter. This field will be used to add periodic mode support to the software timer adapter in DPDK 22.11.
  • eventdev: The function pointer declaration eventdev_stop_flush_t will be renamed to rte_eventdev_stop_flush_t in DPDK 22.11.
  • eventdev: The element *u64s in the structure rte_event_vector is deprecated and will be replaced with u64s in DPDK 22.11.
  • eventdev: The structure rte_event_vector will be modified to include elem_offset:12 bits taken from rsvd:15. The elem_offset defines the offset into the vector array from which valid elements are present. The difference between rte_event_vector::nb_elem and rte_event_vector::elem_offset gives the number of valid elements left to process from the rte_event_vector::elem_offset.
  • eventdev: New fields to represent event queue weight and affinity will be added to rte_event_queue_conf structure in DPDK 22.11.
  • metrics: The function rte_metrics_init will have a non-void return in order to notify errors instead of calling rte_exit.
  • telemetry: The allowed characters in names for dictionary values will be limited to alphanumeric characters and a small subset of additional printable characters. This will ensure that all dictionary parameter names can be output without escaping in JSON - or in any future output format used. Names for the telemetry commands will be similarly limited. The parameters for telemetry commands are unaffected by this change.
  • net/octeontx_ep: The driver octeontx_ep was to support OCTEON TX line of products. It will be renamed to octeon_ep in DPDK 22.11 to apply for all OCTEON EP products: OCTEON TX and future OCTEON chipsets.
  • raw/dpaa2_cmdif: The dpaa2_cmdif rawdev driver will be deprecated in DPDK 22.11, as it is no longer in use, no active user known.
  • raw/ifgpa: The function rte_pmd_ifpga_get_pci_bus will be removed in DPDK 22.11.
  • raw/ioat: The ioat rawdev driver has been deprecated, since it’s functionality is provided through the new dmadev infrastructure. To continue to use hardware previously supported by the ioat rawdev driver, applications should be updated to use the dmadev library instead, with the underlying HW-functionality being provided by the ioat or idxd dma drivers