[v3,2/3] event/dsw: make use of eventdev maintenance facility
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Commit Message
Set the RTE_EVENT_DEV_CAP_REQUIRES_MAINT flag, and perform DSW
background tasks on rte_event_maintain() calls.
PATCH v3:
- Add support for output buffer flushing by means of the new
rte_event_maintain() op parameter, and RTE_EVENT_DEV_MAINT_OP_FLUSH.
PATCH v2:
- Update DSW documentation.
RFC v2:
- Have dsw_event_maintain() occasionally flush the port output
buffers.
Signed-off-by: Mattias Rönnblom <mattias.ronnblom@ericsson.com>
Tested-by: Richard Eklycke <richard.eklycke@ericsson.com>
Tested-by: Liron Himi <lironh@marvell.com>
---
doc/guides/eventdevs/dsw.rst | 27 +++++++++++++++------------
drivers/event/dsw/dsw_evdev.c | 4 +++-
drivers/event/dsw/dsw_evdev.h | 1 +
drivers/event/dsw/dsw_event.c | 12 ++++++++++++
4 files changed, 31 insertions(+), 13 deletions(-)
@@ -40,20 +40,20 @@ Example:
Limitations
-----------
-Unattended Ports
+Port Maintenance
~~~~~~~~~~~~~~~~
-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.
+The distributed software eventdev uses an internal signaling scheme
+between the ports to achieve load balancing. Therefore, it sets the
+``RTE_EVENT_DEV_CAP_REQUIRES_MAINT`` flag.
-Producer-only ports which currently have no events to enqueue should
-periodically call rte_event_enqueue_burst() with a zero-sized burst.
+During periods when the application thread using a particular port is
+neither attempting to enqueue nor to dequeue events, it must
+repeatedly call rte_event_maintain() on that port.
-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.
+Ports left unmaintained for long periods of time will prevent load
+balancing and cause traffic interruptions on flows which are in the
+process of being migrated.
Output Buffering
~~~~~~~~~~~~~~~~
@@ -66,8 +66,11 @@ 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.
+To immediately flush a port's output buffer, an application may call
+rte_event_maintain() with op set to ``RTE_EVENT_DEV_MAINT_OP_FLUSH``.
+
+Repeated calls to rte_event_maintain() will also flush the output
+buffers.
Priorities
@@ -222,7 +222,8 @@ dsw_info_get(struct rte_eventdev *dev __rte_unused,
RTE_EVENT_DEV_CAP_DISTRIBUTED_SCHED|
RTE_EVENT_DEV_CAP_NONSEQ_MODE|
RTE_EVENT_DEV_CAP_MULTIPLE_QUEUE_PORT|
- RTE_EVENT_DEV_CAP_CARRY_FLOW_ID
+ RTE_EVENT_DEV_CAP_CARRY_FLOW_ID|
+ RTE_EVENT_DEV_CAP_REQUIRES_MAINT
};
}
@@ -441,6 +442,7 @@ dsw_probe(struct rte_vdev_device *vdev)
dev->enqueue_forward_burst = dsw_event_enqueue_forward_burst;
dev->dequeue = dsw_event_dequeue;
dev->dequeue_burst = dsw_event_dequeue_burst;
+ dev->maintain = dsw_event_maintain;
if (rte_eal_process_type() != RTE_PROC_PRIMARY)
return 0;
@@ -271,6 +271,7 @@ uint16_t dsw_event_enqueue_forward_burst(void *port,
uint16_t dsw_event_dequeue(void *port, struct rte_event *ev, uint64_t wait);
uint16_t dsw_event_dequeue_burst(void *port, struct rte_event *events,
uint16_t num, uint64_t wait);
+void dsw_event_maintain(void *port, int op);
int dsw_xstats_get_names(const struct rte_eventdev *dev,
enum rte_event_dev_xstats_mode mode,
@@ -1400,3 +1400,15 @@ dsw_event_dequeue_burst(void *port, struct rte_event *events, uint16_t num,
return dequeued;
}
+
+void dsw_event_maintain(void *port, int op)
+{
+ struct dsw_port *source_port = port;
+ struct dsw_evdev *dsw = source_port->dsw;
+
+ dsw_port_note_op(source_port, 0);
+ dsw_port_bg_process(dsw, source_port);
+
+ if (op & RTE_EVENT_DEV_MAINT_OP_FLUSH)
+ dsw_port_flush_out_buffers(dsw, source_port);
+}