llc: Calculate the average queuing delay of the LLC queues
Use a formula like it is used with TCP. This can help to make
decisions about if frames should be dropped or not at the time
we enqueue them.
This code will store two timeval structs in fron the of the
actual data and compute the average at the time of the dequeue.
diff --git a/src/tbf.cpp b/src/tbf.cpp
index 4c0e845..5d7e4ef 100644
--- a/src/tbf.cpp
+++ b/src/tbf.cpp
@@ -100,12 +100,14 @@
/* the TBF exists, so we must write it in the queue
* we prepend lifetime in front of PDU */
struct timeval *tv;
- struct msgb *llc_msg = msgb_alloc(len + sizeof(*tv),
+ struct msgb *llc_msg = msgb_alloc(len + sizeof(*tv) * 2,
"llc_pdu_queue");
if (!llc_msg)
return -ENOMEM;
tv = (struct timeval *)msgb_put(llc_msg, sizeof(*tv));
gprs_llc::calc_pdu_lifetime(bts, pdu_delay_csec, tv);
+ tv = (struct timeval *)msgb_put(llc_msg, sizeof(*tv));
+ gettimeofday(tv, NULL);
memcpy(msgb_put(llc_msg, len), data, len);
m_llc.enqueue(llc_msg);
tbf_update_ms_class(this, ms_class);
@@ -633,6 +635,7 @@
while ((msg = m_llc.dequeue())) {
tv = (struct timeval *)msg->data;
msgb_pull(msg, sizeof(*tv));
+ msgb_pull(msg, sizeof(*tv));
if (gprs_llc::is_frame_expired(&tv_now, tv)) {
LOGP(DRLCMACDL, LOGL_NOTICE, "%s Discarding LLC PDU "