bssgp: Compute and transmit queue delay
The specification 28.018, allows to transmit the average LLC downlink
queueing delay in FLOW CONTROL BVC messages (BVC Measurement IE, see
GSM 28.018, 10.4.4 and 11.3.7).
This commit extends gprs_bssgp_pcu.cpp to compute the average delay
time between two subsequent FLOW CONTROL BVC messages. The average is
implemented as an arithmetic average without any weighting.
Ticket: OW#1432
Sponsored-by: On-Waves ehf
diff --git a/src/gprs_bssgp_pcu.cpp b/src/gprs_bssgp_pcu.cpp
index bb6f7c5..b0e17f0 100644
--- a/src/gprs_bssgp_pcu.cpp
+++ b/src/gprs_bssgp_pcu.cpp
@@ -553,6 +553,23 @@
return bucket_size;
}
+static uint32_t get_and_reset_avg_queue_delay(void)
+{
+ struct timeval *delay_sum = &the_pcu.queue_delay_sum;
+ uint64_t delay_sum_ms = delay_sum->tv_sec * 1000 +
+ delay_sum->tv_usec / 1000000;
+ uint32_t avg_delay_ms = 0;
+
+ if (the_pcu.queue_delay_count > 0)
+ avg_delay_ms = delay_sum_ms / the_pcu.queue_delay_count;
+
+ /* Reset accumulator */
+ delay_sum->tv_sec = delay_sum->tv_usec = 0;
+ the_pcu.queue_delay_count = 0;
+
+ return avg_delay_ms;
+}
+
int gprs_bssgp_tx_fc_bvc(void)
{
struct gprs_rlcmac_bts *bts;
@@ -560,6 +577,7 @@
uint32_t ms_bucket_size; /* oct */
uint32_t leak_rate; /* oct/s */
uint32_t ms_leak_rate; /* oct/s */
+ uint32_t avg_delay_ms;
int num_pdch = -1;
if (!the_pcu.bctx) {
@@ -621,16 +639,19 @@
if (ms_leak_rate > FC_MAX_BUCKET_LEAK_RATE)
ms_leak_rate = FC_MAX_BUCKET_LEAK_RATE;
- /* TODO: Implement avg queue delay monitoring */
+ /* Avg queue delay monitoring */
+ avg_delay_ms = get_and_reset_avg_queue_delay();
LOGP(DBSSGP, LOGL_DEBUG,
- "Sending FLOW CONTROL BVC, Bmax = %d, R = %d, Bmax_MS = %d, R_MS = %d\n",
- bucket_size, leak_rate, ms_bucket_size, ms_leak_rate);
+ "Sending FLOW CONTROL BVC, Bmax = %d, R = %d, Bmax_MS = %d, "
+ "R_MS = %d, avg_dly = %d\n",
+ bucket_size, leak_rate, ms_bucket_size, ms_leak_rate,
+ avg_delay_ms);
return bssgp_tx_fc_bvc(the_pcu.bctx, 1,
bucket_size, leak_rate,
ms_bucket_size, ms_leak_rate,
- NULL, NULL);
+ NULL, &avg_delay_ms);
}
static void bvc_timeout(void *_priv)
@@ -763,3 +784,15 @@
{
return the_pcu.bctx;
}
+
+void gprs_bssgp_update_queue_delay(struct timeval *tv_recv,
+ struct timeval *tv_now)
+{
+ struct timeval *delay_sum = &the_pcu.queue_delay_sum;
+ struct timeval tv_delay;
+
+ timersub(tv_now, tv_recv, &tv_delay);
+ timeradd(delay_sum, &tv_delay, delay_sum);
+
+ the_pcu.queue_delay_count += 1;
+}