-.. BSD LICENSE
- Copyright(c) 2017 Intel Corporation. All rights reserved.
-
- Redistribution and use in source and binary forms, with or without
- modification, are permitted provided that the following conditions
- are met:
-
- * Redistributions of source code must retain the above copyright
- notice, this list of conditions and the following disclaimer.
- * Redistributions in binary form must reproduce the above copyright
- notice, this list of conditions and the following disclaimer in
- the documentation and/or other materials provided with the
- distribution.
- * Neither the name of Intel Corporation nor the names of its
- contributors may be used to endorse or promote products derived
- from this software without specific prior written permission.
-
- THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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- LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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- OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+.. SPDX-License-Identifier: BSD-3-Clause
+ Copyright(c) 2017 Intel Corporation.
Software Eventdev Poll Mode Driver
==================================
The software eventdev is an implementation of the eventdev API, that provides a
wide range of the eventdev features. The eventdev relies on a CPU core to
-perform event scheduling.
+perform event scheduling. This PMD can use the service core library to run the
+scheduling function, allowing an application to utilize the power of service
+cores to multiplex other work on the same core if required.
Features
The software eventdev is a vdev device, and as such can be created from the
application code, or from the EAL command line:
-* Call ``rte_eal_vdev_init("event_sw0")`` from the application
+* Call ``rte_vdev_init("event_sw0")`` from the application
* Use ``--vdev="event_sw0"`` in the EAL options, which will call
- rte_eal_vdev_init() internally
+ rte_vdev_init() internally
Example:
~~~~~~~~~~~~~~~~~
The scheduling quanta sets the number of events that the device attempts to
-schedule before returning to the application from the ``rte_event_schedule()``
-function. Note that is a *hint* only, and that fewer or more events may be
-scheduled in a given iteration.
+schedule in a single schedule call performed by the service core. Note that
+is a *hint* only, and that fewer or more events may be scheduled in a given
+iteration.
The scheduling quanta can be set using a string argument to the vdev
create call:
The credit quanta is the number of credits that a port will fetch at a time from
the instance's credit pool. Higher numbers will cause less overhead in the
atomic credit fetch code, however it also reduces the overall number of credits
-in the system faster. A balanced number (eg 32) ensures that only small numbers
+in the system faster. A balanced number (e.g. 32) ensures that only small numbers
of credits are pre-allocated at a time, while also mitigating performance impact
of the atomics.
~~~~~~~~~~~~~~~~~~
The software eventdev does not support creating queues that handle all types of
-traffic. An eventdev with this capability allows enqueueing Atomic, Ordered and
+traffic. An eventdev with this capability allows enqueuing Atomic, Ordered and
Parallel traffic to the same queue, but scheduling each of them appropriately.
The reason to not allow Atomic, Ordered and Parallel event types in the
Distributed Scheduler
~~~~~~~~~~~~~~~~~~~~~
-The software eventdev is a centralized scheduler, requiring the
-``rte_event_schedule()`` function to be called by a CPU core to perform the
-required event distribution. This is not really a limitation but rather a
-design decision.
+The software eventdev is a centralized scheduler, requiring a service core to
+perform the required event distribution. This is not really a limitation but
+rather a design decision.
The ``RTE_EVENT_DEV_CAP_DISTRIBUTED_SCHED`` flag is not set in the
``event_dev_cap`` field of the ``rte_event_dev_info`` struct for the software