X-Git-Url: http://git.droids-corp.org/?a=blobdiff_plain;f=doc%2Fguides%2Fprog_guide%2Fevent_ethernet_rx_adapter.rst;h=c7dda92215ea44d438497d7e0206f099147dffd3;hb=47909357a0697fe9aaf4f0f27939f4edcdbb5e22;hp=319e4f0557a191cc4a941949b45a2e67ad87e536;hpb=569758758dcd9bece5f2cc079f7e427a227040cd;p=dpdk.git diff --git a/doc/guides/prog_guide/event_ethernet_rx_adapter.rst b/doc/guides/prog_guide/event_ethernet_rx_adapter.rst index 319e4f0557..c7dda92215 100644 --- a/doc/guides/prog_guide/event_ethernet_rx_adapter.rst +++ b/doc/guides/prog_guide/event_ethernet_rx_adapter.rst @@ -135,6 +135,11 @@ This function calls the start callbacks of the eventdev PMDs for hardware based eventdev-ethdev connections and ``rte_service_run_state_set()`` to enable the service function if one exists. +.. Note:: + + The eventdev to which the event_eth_rx_adapter is connected needs to + be started before calling rte_event_eth_rx_adapter_start(). + Getting Adapter Statistics ~~~~~~~~~~~~~~~~~~~~~~~~~~ @@ -144,3 +149,44 @@ enqueued event counts are a sum of the counts from the eventdev PMD callbacks if the callback is supported, and the counts maintained by the service function, if one exists. The service function also maintains a count of cycles for which it was not able to enqueue to the event device. + +Interrupt Based Rx Queues +~~~~~~~~~~~~~~~~~~~~~~~~~~ + +The service core function is typically set up to poll ethernet Rx queues for +packets. Certain queues may have low packet rates and it would be more +efficient to enable the Rx queue interrupt and read packets after receiving +the interrupt. + +The servicing_weight member of struct rte_event_eth_rx_adapter_queue_conf +is applicable when the adapter uses a service core function. The application +has to enable Rx queue interrupts when configuring the ethernet device +using the ``rte_eth_dev_configure()`` function and then use a servicing_weight +of zero when adding the Rx queue to the adapter. + +The adapter creates a thread blocked on the interrupt, on an interrupt this +thread enqueues the port id and the queue id to a ring buffer. The adapter +service function dequeues the port id and queue id from the ring buffer, +invokes the ``rte_eth_rx_burst()`` to receive packets on the queue and +converts the received packets to events in the same manner as packets +received on a polled Rx queue. The interrupt thread is affinitized to the same +CPUs as the lcores of the Rx adapter service function, if the Rx adapter +service function has not been mapped to any lcores, the interrupt thread +is mapped to the master lcore. + +Rx Callback for SW Rx Adapter +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +For SW based packet transfers, i.e., when the +``RTE_EVENT_ETH_RX_ADAPTER_CAP_INTERNAL_PORT`` is not set in the adapter's +capabilities flags for a particular ethernet device, the service function +temporarily enqueues mbufs to an event buffer before batch enqueuing these +to the event device. If the buffer fills up, the service function stops +dequeuing packets from the ethernet device. The application may want to +monitor the buffer fill level and instruct the service function to selectively +enqueue packets to the event device. The application may also use some other +criteria to decide which packets should enter the event device even when +the event buffer fill level is low. The +``rte_event_eth_rx_adapter_cb_register()`` function allow the application +to register a callback that selects which packets to enqueue to the event +device.