diff options
author | Luca Boccassi <luca.boccassi@gmail.com> | 2018-11-01 11:59:50 +0000 |
---|---|---|
committer | Luca Boccassi <luca.boccassi@gmail.com> | 2018-11-01 12:00:19 +0000 |
commit | 8d01b9cd70a67cdafd5b965a70420c3bd7fb3f82 (patch) | |
tree | 208e3bc33c220854d89d010e3abf720a2e62e546 /doc/guides/eventdevs/dsw.rst | |
parent | b63264c8342e6a1b6971c79550d2af2024b6a4de (diff) |
New upstream version 18.11-rc1upstream/18.11-rc1
Change-Id: Iaa71986dd6332e878d8f4bf493101b2bbc6313bb
Signed-off-by: Luca Boccassi <luca.boccassi@gmail.com>
Diffstat (limited to 'doc/guides/eventdevs/dsw.rst')
-rw-r--r-- | doc/guides/eventdevs/dsw.rst | 96 |
1 files changed, 96 insertions, 0 deletions
diff --git a/doc/guides/eventdevs/dsw.rst b/doc/guides/eventdevs/dsw.rst new file mode 100644 index 00000000..6653f501 --- /dev/null +++ b/doc/guides/eventdevs/dsw.rst @@ -0,0 +1,96 @@ +.. SPDX-License-Identifier: BSD-3-Clause + Copyright(c) 2018 Ericsson AB + +Distributed Software Eventdev Poll Mode Driver +============================================== + +The distributed software event device is an eventdev driver which +distributes the task of scheduling events among all the eventdev ports +and the lcore threads using them. + +Features +-------- + +Queues + * Atomic + * Parallel + * Single-Link + +Ports + * Load balanced (for Atomic, Ordered, Parallel queues) + * Single Link (for single-link queues) + +Configuration and Options +------------------------- + +The distributed software eventdev is a vdev device, and as such can be +created from the application code, or from the EAL command line: + +* Call ``rte_vdev_init("event_dsw0")`` from the application + +* Use ``--vdev="event_dsw0"`` in the EAL options, which will call + rte_vdev_init() internally + +Example: + +.. code-block:: console + + ./your_eventdev_application --vdev="event_dsw0" + +Limitations +----------- + +Unattended Ports +~~~~~~~~~~~~~~~~ + +The distributed software eventdev uses an internal signaling schema +between the ports to achieve load balancing. In order for this to +work, the application must perform enqueue and/or dequeue operations +on all ports. + +Producer-only ports which currently have no events to enqueue should +periodically call rte_event_enqueue_burst() with a zero-sized burst. + +Ports left unattended for longer periods of time will prevent load +balancing, and also cause traffic interruptions on the flows which +are in the process of being migrated. + +Output Buffering +~~~~~~~~~~~~~~~~ + +For efficiency reasons, the distributed software eventdev might not +send enqueued events immediately to the destination port, but instead +store them in an internal buffer in the source port. + +In case no more events are enqueued on a port with buffered events, +these events will be sent after the application has performed a number +of enqueue and/or dequeue operations. + +For explicit flushing, an application may call +rte_event_enqueue_burst() with a zero-sized burst. + + +Priorities +~~~~~~~~~~ + +The distributed software eventdev does not support event priorities. + +Ordered Queues +~~~~~~~~~~~~~~ + +The distributed software eventdev does not support the ordered queue type. + + +"All Types" Queues +~~~~~~~~~~~~~~~~~~ + +The distributed software eventdev does not support queues of type +RTE_EVENT_QUEUE_CFG_ALL_TYPES, which allow both atomic, ordered, and +parallel events on the same queue. + +Dynamic Link/Unlink +~~~~~~~~~~~~~~~~~~~ + +The distributed software eventdev does not support calls to +rte_event_port_link() or rte_event_port_unlink() after +rte_event_dev_start() has been called. |