app/testpmd: display Rx queue used descriptor count

[dpdk.git] / doc / guides / eventdevs / dlb.rst

diff --git a/doc/guides/eventdevs/dlb.rst b/doc/guides/eventdevs/dlb.rst
index 7e2fefb..d44afcd 100644 (file)
--- a/doc/guides/eventdevs/dlb.rst
+++ b/doc/guides/eventdevs/dlb.rst
@@ -318,3 +318,24 @@ increase a vdev's per-queue atomic-inflight allocation to (for example) 64:
 
        --vdev=dlb1_event,atm_inflights=64
 
+Deferred Scheduling
+~~~~~~~~~~~~~~~~~~~
+
+The DLB PMD's default behavior for managing a CQ is to "pop" the CQ once per
+dequeued event before returning from rte_event_dequeue_burst(). This frees the
+corresponding entries in the CQ, which enables the DLB to schedule more events
+to it.
+
+To support applications seeking finer-grained scheduling control -- for example
+deferring scheduling to get the best possible priority scheduling and
+load-balancing -- the PMD supports a deferred scheduling mode. In this mode,
+the CQ entry is not popped until the *subsequent* rte_event_dequeue_burst()
+call. This mode only applies to load-balanced event ports with dequeue depth of
+1.
+
+To enable deferred scheduling, use the defer_sched vdev argument like so:
+
+    .. code-block:: console
+
+       --vdev=dlb1_event,defer_sched=on
+