- Open system with configurable amount of outstanding events limited only by
DRAM
- HW accelerated dequeue timeout support to enable power management
+- HW managed event timers support through TIM, with high precision and
+ time granularity of 2.5us on CN9K and 1us on CN10K.
+- Up to 256 TIM rings a.k.a event timer adapters.
+- Up to 8 rings traversed in parallel.
+- HW managed packets enqueued from ethdev to eventdev exposed through event eth
+ RX adapter.
+- N:1 ethernet device Rx queue to Event queue mapping.
+- Lockfree Tx from event eth Tx adapter using ``RTE_ETH_TX_OFFLOAD_MT_LOCKFREE``
+ capability while maintaining receive packet order.
+- Full Rx/Tx offload support defined through ethdev queue configuration.
+- HW managed event vectorization on CN10K for packets enqueued from ethdev to
+ eventdev configurable per each Rx queue in Rx adapter.
+- Event vector transmission via Tx adapter.
Prerequisites and Compilation procedure
---------------------------------------
See :doc:`../platform/cnxk` for setup information.
+
+Runtime Config Options
+----------------------
+
+- ``Maximum number of in-flight events`` (default ``8192``)
+
+ In **Marvell OCTEON cnxk** the max number of in-flight events are only limited
+ by DRAM size, the ``xae_cnt`` devargs parameter is introduced to provide
+ upper limit for in-flight events.
+
+ For example::
+
+ -a 0002:0e:00.0,xae_cnt=16384
+
+- ``CN9K Getwork mode``
+
+ CN9K ``single_ws`` devargs parameter is introduced to select single workslot
+ mode in SSO and disable the default dual workslot mode.
+
+ For example::
+
+ -a 0002:0e:00.0,single_ws=1
+
+- ``CN10K Getwork mode``
+
+ CN10K supports multiple getwork prefetch modes, by default the prefetch
+ mode is set to none.
+
+ For example::
+
+ -a 0002:0e:00.0,gw_mode=1
+
+- ``Event Group QoS support``
+
+ SSO GGRPs i.e. queue uses DRAM & SRAM buffers to hold in-flight
+ events. By default the buffers are assigned to the SSO GGRPs to
+ satisfy minimum HW requirements. SSO is free to assign the remaining
+ buffers to GGRPs based on a preconfigured threshold.
+ We can control the QoS of SSO GGRP by modifying the above mentioned
+ thresholds. GGRPs that have higher importance can be assigned higher
+ thresholds than the rest. The dictionary format is as follows
+ [Qx-XAQ-TAQ-IAQ][Qz-XAQ-TAQ-IAQ] expressed in percentages, 0 represents
+ default.
+
+ For example::
+
+ -a 0002:0e:00.0,qos=[1-50-50-50]
+
+- ``Force Rx Back pressure``
+
+ Force Rx back pressure when same mempool is used across ethernet device
+ connected to event device.
+
+ For example::
+
+ -a 0002:0e:00.0,force_rx_bp=1
+
+- ``TIM disable NPA``
+
+ By default chunks are allocated from NPA then TIM can automatically free
+ them when traversing the list of chunks. The ``tim_disable_npa`` devargs
+ parameter disables NPA and uses software mempool to manage chunks
+
+ For example::
+
+ -a 0002:0e:00.0,tim_disable_npa=1
+
+- ``TIM modify chunk slots``
+
+ The ``tim_chnk_slots`` devargs can be used to modify number of chunk slots.
+ Chunks are used to store event timers, a chunk can be visualised as an array
+ where the last element points to the next chunk and rest of them are used to
+ store events. TIM traverses the list of chunks and enqueues the event timers
+ to SSO. The default value is 255 and the max value is 4095.
+
+ For example::
+
+ -a 0002:0e:00.0,tim_chnk_slots=1023
+
+- ``TIM enable arm/cancel statistics``
+
+ The ``tim_stats_ena`` devargs can be used to enable arm and cancel stats of
+ event timer adapter.
+
+ For example::
+
+ -a 0002:0e:00.0,tim_stats_ena=1
+
+- ``TIM limit max rings reserved``
+
+ The ``tim_rings_lmt`` devargs can be used to limit the max number of TIM
+ rings i.e. event timer adapter reserved on probe. Since, TIM rings are HW
+ resources we can avoid starving other applications by not grabbing all the
+ rings.
+
+ For example::
+
+ -a 0002:0e:00.0,tim_rings_lmt=5
+
+- ``TIM ring control internal parameters``
+
+ When using multiple TIM rings the ``tim_ring_ctl`` devargs can be used to
+ control each TIM rings internal parameters uniquely. The following dict
+ format is expected [ring-chnk_slots-disable_npa-stats_ena]. 0 represents
+ default values.
+
+ For Example::
+
+ -a 0002:0e:00.0,tim_ring_ctl=[2-1023-1-0]
+
Debugging Options
-----------------
+===+============+=======================================================+
| 1 | SSO | --log-level='pmd\.event\.cnxk,8' |
+---+------------+-------------------------------------------------------+
+ | 2 | TIM | --log-level='pmd\.event\.cnxk\.timer,8' |
+ +---+------------+-------------------------------------------------------+
+
+Limitations
+-----------
+
+Rx adapter support
+~~~~~~~~~~~~~~~~~~
+
+Using the same mempool for all the ethernet device ports connected to
+event device would cause back pressure to be asserted only on the first
+ethernet device.
+Back pressure is automatically disabled when using same mempool for all the
+ethernet devices connected to event device to override this applications can
+use `force_rx_bp=1` device arguments.
+Using unique mempool per each ethernet device is recommended when they are
+connected to event device.
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