On Fri, Feb 2, 2024 at 7:29 PM Bruce Richardson
<bruce.richard...@intel.com> wrote:
Make some textual improvements to the introduction to eventdev and event
devices in the eventdev header file. This text appears in the doxygen
output for the header file, and introduces the key concepts, for
example: events, event devices, queues, ports and scheduling.
This patch makes the following improvements:
* small textual fixups, e.g. correcting use of singular/plural
* rewrites of some sentences to improve clarity
* using doxygen markdown to split the whole large block up into
sections, thereby making it easier to read.
No large-scale changes are made, and blocks are not reordered
Signed-off-by: Bruce Richardson <bruce.richard...@intel.com>
Thanks Bruce, While you are cleaning up, Please add following or
similar change to fix for not properly
parsing the struct rte_event_vector. i.e it is coming as global
variables in html files.
l[dpdk.org] $ git diff
diff --git a/lib/eventdev/rte_eventdev.h b/lib/eventdev/rte_eventdev.h
index e31c927905..ce4a195a8f 100644
--- a/lib/eventdev/rte_eventdev.h
+++ b/lib/eventdev/rte_eventdev.h
@@ -1309,9 +1309,9 @@ struct rte_event_vector {
*/
struct {
uint16_t port;
- /* Ethernet device port id. */
+ /**< Ethernet device port id. */
uint16_t queue;
- /* Ethernet device queue id. */
+ /**< Ethernet device queue id. */
};
};
/**< Union to hold common attributes of the vector array. */
@@ -1340,7 +1340,11 @@ struct rte_event_vector {
* vector array can be an array of mbufs or pointers or opaque u64
* values.
*/
+#ifndef __DOXYGEN__
} __rte_aligned(16);
+#else
+};
+#endif
/* Scheduler type definitions */
#define RTE_SCHED_TYPE_ORDERED 0
---
V3: reworked following feedback from Mattias
---
lib/eventdev/rte_eventdev.h | 132 ++++++++++++++++++++++--------------
1 file changed, 81 insertions(+), 51 deletions(-)
diff --git a/lib/eventdev/rte_eventdev.h b/lib/eventdev/rte_eventdev.h
index ec9b02455d..a741832e8e 100644
--- a/lib/eventdev/rte_eventdev.h
+++ b/lib/eventdev/rte_eventdev.h
@@ -12,25 +12,33 @@
* @file
*
* RTE Event Device API
+ * ====================
*
- * In a polling model, lcores poll ethdev ports and associated rx queues
- * directly to look for packet. In an event driven model, by contrast, lcores
- * call the scheduler that selects packets for them based on programmer
- * specified criteria. Eventdev library adds support for event driven
- * programming model, which offer applications automatic multicore scaling,
- * dynamic load balancing, pipelining, packet ingress order maintenance and
- * synchronization services to simplify application packet processing.
+ * In a traditional run-to-completion application model, lcores pick up packets
Can we keep it is as poll mode instead of run-to-completion as event mode also
supports run to completion by having dequuee() and then Tx.
+ * from Ethdev ports and associated RX queues, run the packet processing to
completion,
+ * and enqueue the completed packets to a TX queue. NIC-level receive-side
scaling (RSS)
+ * may be used to balance the load across multiple CPU cores.
+ *
+ * In contrast, in an event-driver model, as supported by this "eventdev"
library,
+ * incoming packets are fed into an event device, which schedules those
packets across
packets -> events. We may need to bring in Rx adapter if the event is packet.
+ * the available lcores, in accordance with its configuration.
+ * This event-driven programming model offers applications automatic multicore
scaling,
+ * dynamic load balancing, pipelining, packet order maintenance,
synchronization,
+ * and prioritization/quality of service.
*
* The Event Device API is composed of two parts:
*
* - The application-oriented Event API that includes functions to setup
* an event device (configure it, setup its queues, ports and start it), to
- * establish the link between queues to port and to receive events, and so
on.
+ * establish the links between queues and ports to receive events, and so on.
*
* - The driver-oriented Event API that exports a function allowing
- * an event poll Mode Driver (PMD) to simultaneously register itself as
+ * an event poll Mode Driver (PMD) to register itself as
* an event device driver.
*
+ * Application-oriented Event API
+ * ------------------------------
+ *
* Event device components:
*
* +-----------------+
@@ -75,27 +83,39 @@
* | |
* +-----------------------------------------------------------+
*
- * Event device: A hardware or software-based event scheduler.
+ * **Event device**: A hardware or software-based event scheduler.
*
- * Event: A unit of scheduling that encapsulates a packet or other datatype
- * like SW generated event from the CPU, Crypto work completion notification,
- * Timer expiry event notification etc as well as metadata.
- * The metadata includes flow ID, scheduling type, event priority, event_type,
- * sub_event_type etc.
+ * **Event**: Represents an item of work and is the smallest unit of
scheduling.
+ * An event carries metadata, such as queue ID, scheduling type, and event
priority,
+ * and data such as one or more packets or other kinds of buffers.
+ * Some examples of events are:
+ * - a software-generated item of work originating from a lcore,
lcore.
+ * perhaps carrying a packet to be processed,
processed.
+ * - a crypto work completion notification
notification.
+ * - a timer expiry notification.
*
- * Event queue: A queue containing events that are scheduled by the event dev.
+ * **Event queue**: A queue containing events that are scheduled by the event
device.
Shouldn't we add "to be" or so?
i.e
A queue containing events that are to be scheduled by the event device.
* An event queue contains events of different flows associated with
scheduling
* types, such as atomic, ordered, or parallel.
+ * Each event given to an event device must have a valid event queue id field
in the metadata,
+ * to specify on which event queue in the device the event must be placed,
+ * for later scheduling.
*
- * Event port: An application's interface into the event dev for enqueue and
+ * **Event port**: An application's interface into the event dev for enqueue
and
* dequeue operations. Each event port can be linked with one or more
* event queues for dequeue operations.
- *
- * By default, all the functions of the Event Device API exported by a PMD
- * are lock-free functions which assume to not be invoked in parallel on
- * different logical cores to work on the same target object. For instance,
- * the dequeue function of a PMD cannot be invoked in parallel on two logical
- * cores to operates on same event port. Of course, this function
+ * Enqueue and dequeue from a port is not thread-safe, and the expected
use-case is
+ * that each port is polled by only a single lcore. [If this is not the case,
+ * a suitable synchronization mechanism should be used to prevent simultaneous
+ * access from multiple lcores.]
+ * To schedule events to an lcore, the event device will schedule them to the
event port(s)
+ * being polled by that lcore.
+ *
+ * *NOTE*: By default, all the functions of the Event Device API exported by a
PMD
+ * are non-thread-safe functions, which must not be invoked on the same object
in parallel on
+ * different logical cores.
+ * For instance, the dequeue function of a PMD cannot be invoked in parallel
on two logical
+ * cores to operate on same event port. Of course, this function
* can be invoked in parallel by different logical cores on different ports.
* It is the responsibility of the upper level application to enforce this
rule.
*
@@ -107,22 +127,19 @@
*
* Event devices are dynamically registered during the PCI/SoC device probing
* phase performed at EAL initialization time.
- * When an Event device is being probed, a *rte_event_dev* structure and
- * a new device identifier are allocated for that device. Then, the
- * event_dev_init() function supplied by the Event driver matching the probed
- * device is invoked to properly initialize the device.
+ * When an Event device is being probed, an *rte_event_dev* structure is
allocated
+ * for it and the event_dev_init() function supplied by the Event driver
+ * is invoked to properly initialize the device.
*
- * The role of the device init function consists of resetting the hardware or
- * software event driver implementations.
+ * The role of the device init function is to reset the device hardware or
+ * to initialize the software event driver implementation.
*
- * If the device init operation is successful, the correspondence between
- * the device identifier assigned to the new device and its associated
- * *rte_event_dev* structure is effectively registered.
- * Otherwise, both the *rte_event_dev* structure and the device identifier are
- * freed.
+ * If the device init operation is successful, the device is assigned a device
+ * id (dev_id) for application use.
+ * Otherwise, the *rte_event_dev* structure is freed.
*
* The functions exported by the application Event API to setup a device
- * designated by its device identifier must be invoked in the following order:
+ * must be invoked in the following order:
* - rte_event_dev_configure()
* - rte_event_queue_setup()
* - rte_event_port_setup()
@@ -130,10 +147,15 @@
* - rte_event_dev_start()
*
* Then, the application can invoke, in any order, the functions
- * exported by the Event API to schedule events, dequeue events, enqueue
events,
- * change event queue(s) to event port [un]link establishment and so on.
- *
- * Application may use rte_event_[queue/port]_default_conf_get() to get the
+ * exported by the Event API to dequeue events, enqueue events,
+ * and link and unlink event queue(s) to event ports.
+ *
+ * Before configuring a device, an application should call
rte_event_dev_info_get()
+ * to determine the capabilities of the event device, and any queue or port
+ * limits of that device. The parameters set in the various device
configuration
+ * structures may need to be adjusted based on the max values provided in the
+ * device information structure returned from the info_get API.
Can we add full name of info_get()?
