We are sending data to controller at wrong average rate not equal to
1 packet / SDU interval, if Transport_Latency is not an integer multiple
of SDU_Interval. The calculation currently may also give zero, so no
data gets sent.
We are sending data in bursts of num ~= Transport_Latency/SDU_Interval
packets, in hopes that possibly larger timer interval makes things more
efficient.
Fix the data rate by sending num packets every num*SDU_Interval, so that
the average data rate is correct.
Also fix use of itimerspect.it_value with TFD_TIMER_ABSTIME. The value
set previously is going to always be in the past in CLOCK_MONOTONIC so
just set it to 1.
---
Notes:
v2: Buffer one interval immediately as before.
This assumes kernel shall set qos.interval to SDU_Interval and not
ISO_Interval.
client/player.c | 19 ++++++++++++++-----
1 file changed, 14 insertions(+), 5 deletions(-)
diff --git a/client/player.c b/client/player.c
index 7f67425aa..df5cb8924 100644
--- a/client/player.c
+++ b/client/player.c
@@ -5066,21 +5066,30 @@ static int transport_send(struct transport *transport, int fd,
if (timer_fd < 0)
return -errno;
+ /* Send data in bursts of
+ * num = ROUND_CLOSEST(Transport_Latency (ms) / SDU_Interval (us))
+ * with average data rate = 1 packet / SDU_Interval
+ */
+ transport->num = ROUND_CLOSEST(qos->latency * 1000, qos->interval);
+ if (!transport->num)
+ transport->num = 1;
+
memset(&ts, 0, sizeof(ts));
- ts.it_value.tv_nsec = qos->latency * 1000000;
- ts.it_interval.tv_nsec = qos->latency * 1000000;
+ ts.it_value.tv_nsec = 1;
+ ts.it_interval.tv_nsec = transport->num * qos->interval * 1000;
- if (timerfd_settime(timer_fd, TFD_TIMER_ABSTIME, &ts, NULL) < 0)
+ if (timerfd_settime(timer_fd, TFD_TIMER_ABSTIME, &ts, NULL) < 0) {
+ close(timer_fd);
return -errno;
+ }
transport->fd = fd;
- /* num of packets = ROUND_CLOSEST(latency (ms) / interval (us)) */
- transport->num = ROUND_CLOSEST(qos->latency * 1000, qos->interval);
transport->timer_io = io_new(timer_fd);
io_set_read_handler(transport->timer_io, transport_timer_read,
transport, NULL);
+ /* One extra packet to buffers immediately */
return transport_send_seq(transport, fd, 1);
}
--
2.45.0
