event/dsw: reduce latency in low-load situations

In DSW, in case a port can't produce any events for the application to
consume, the port is considered idle.

To slightly reduce wall-time latency, flush the port's output buffer
in case of such an empty dequeue.

Signed-off-by: Mattias Rönnblom <mattias.ronnblom@ericsson.com>
This commit is contained in:
Mattias Rönnblom 2020-03-09 07:50:59 +01:00 committed by Jerin Jacob
parent aeb2494688
commit 3db0a0984f

View File

@ -1242,11 +1242,11 @@ dsw_event_dequeue_burst(void *port, struct rte_event *events, uint16_t num,
* seem to improve performance.
*/
dsw_port_record_seen_events(port, events, dequeued);
}
/* XXX: Assuming the port can't produce any more work,
* consider flushing the output buffer, on dequeued ==
* 0.
*/
} else /* Zero-size dequeue means a likely idle port, and thus
* we can afford trading some efficiency for a slightly
* reduced event wall-time latency.
*/
dsw_port_flush_out_buffers(dsw, port);
#ifdef DSW_SORT_DEQUEUED
dsw_stable_sort(events, dequeued, sizeof(events[0]), dsw_cmp_event);