- 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
---------------------------------------
-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.