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authorOliver Smith <osmith@sysmocom.de>2019-09-05 15:12:20 +0200
committerOliver Smith <osmith@sysmocom.de>2019-09-05 15:36:37 +0200
commitca581d5d0c619c467ad54cbe5f65a87cb8fe68e3 (patch)
tree4639fefde09377002c18e0010001c90bb76f2c84
parentee8edd9e33483daec7675a2e6c27ce07cefa5396 (diff)
tbf_dl: make preemptive re-transmission optionalosmith/preemptive-retransmission
Since [1], OsmoPCU already starts to re-transmit downlink blocks before the MS has had a chance to receive them and/or send the related acknowledgement in uplink. Make this optional with the new VTY option "no dl-tbf-preemptive-retransmission". [1] e25b5b91f60f20f61096bc6199a05b58ee6c6328 ("tbf: Only create dummy frames if necessary") Related: OS#2408 Change-Id: Id08aed513d4033aa0d4324c6ce07cbb2852f2f92
-rw-r--r--src/bts.cpp1
-rw-r--r--src/bts.h1
-rw-r--r--src/pcu_vty.c30
-rw-r--r--src/tbf_dl.cpp2
4 files changed, 33 insertions, 1 deletions
diff --git a/src/bts.cpp b/src/bts.cpp
index 26dd401..60f74dd 100644
--- a/src/bts.cpp
+++ b/src/bts.cpp
@@ -216,6 +216,7 @@ BTS::BTS()
{
memset(&m_bts, 0, sizeof(m_bts));
m_bts.bts = this;
+ m_bts.dl_tbf_preemptive_retransmission = true;
/* initialize back pointers */
for (size_t trx_no = 0; trx_no < ARRAY_SIZE(m_bts.trx); ++trx_no) {
diff --git a/src/bts.h b/src/bts.h
index 767605c..45d52a9 100644
--- a/src/bts.h
+++ b/src/bts.h
@@ -135,6 +135,7 @@ struct gprs_rlcmac_bts {
uint8_t alpha, gamma;
uint8_t egprs_enabled;
uint32_t dl_tbf_idle_msec; /* hold time for idle DL TBFs */
+ bool dl_tbf_preemptive_retransmission;
uint8_t si13[GSM_MACBLOCK_LEN];
bool si13_is_set;
/* 0 to support resegmentation in DL, 1 for no reseg */
diff --git a/src/pcu_vty.c b/src/pcu_vty.c
index 1e4f50c..f444e41 100644
--- a/src/pcu_vty.c
+++ b/src/pcu_vty.c
@@ -254,6 +254,8 @@ static int config_write_pcu(struct vty *vty)
if (bts->dl_tbf_idle_msec)
vty_out(vty, " dl-tbf-idle-time %d%s", bts->dl_tbf_idle_msec,
VTY_NEWLINE);
+ if (!bts->dl_tbf_preemptive_retransmission)
+ vty_out(vty, " no dl-tbf-preemptive-retransmission%s", VTY_NEWLINE);
if (strcmp(bts->pcu_sock_path, PCU_SOCK_DEFAULT))
vty_out(vty, " pcu-socket %s%s", bts->pcu_sock_path, VTY_NEWLINE);
@@ -870,6 +872,32 @@ DEFUN(cfg_pcu_no_dl_tbf_idle_time,
return CMD_SUCCESS;
}
+#define RETRANSMISSION_STR "re-transmit blocks even before the MS had a chance to receive them (better throughput," \
+ " less readable traces)"
+DEFUN(cfg_pcu_dl_tbf_preemptive_retransmission,
+ cfg_pcu_dl_tbf_preemptive_retransmission_cmd,
+ "dl-tbf-preemptive-retransmission",
+ RETRANSMISSION_STR " (enabled by default)")
+{
+ struct gprs_rlcmac_bts *bts = bts_main_data();
+
+ bts->dl_tbf_preemptive_retransmission = true;
+
+ return CMD_SUCCESS;
+}
+
+DEFUN(cfg_pcu_no_dl_tbf_preemptive_retransmission,
+ cfg_pcu_no_dl_tbf_preemptive_retransmission_cmd,
+ "no dl-tbf-preemptive-retransmission",
+ NO_STR RETRANSMISSION_STR)
+{
+ struct gprs_rlcmac_bts *bts = bts_main_data();
+
+ bts->dl_tbf_preemptive_retransmission = false;
+
+ return CMD_SUCCESS;
+}
+
#define MS_IDLE_TIME_STR "keep an idle MS object alive for the time given\n"
DEFUN(cfg_pcu_ms_idle_time,
cfg_pcu_ms_idle_time_cmd,
@@ -1215,6 +1243,8 @@ int pcu_vty_init(void)
install_element(PCU_NODE, &cfg_pcu_gamma_cmd);
install_element(PCU_NODE, &cfg_pcu_dl_tbf_idle_time_cmd);
install_element(PCU_NODE, &cfg_pcu_no_dl_tbf_idle_time_cmd);
+ install_element(PCU_NODE, &cfg_pcu_dl_tbf_preemptive_retransmission_cmd);
+ install_element(PCU_NODE, &cfg_pcu_no_dl_tbf_preemptive_retransmission_cmd);
install_element(PCU_NODE, &cfg_pcu_ms_idle_time_cmd);
install_element(PCU_NODE, &cfg_pcu_no_ms_idle_time_cmd);
install_element(PCU_NODE, &cfg_pcu_gsmtap_categ_cmd);
diff --git a/src/tbf_dl.cpp b/src/tbf_dl.cpp
index d5e4a45..71fde66 100644
--- a/src/tbf_dl.cpp
+++ b/src/tbf_dl.cpp
@@ -431,7 +431,7 @@ int gprs_rlcmac_dl_tbf::take_next_bsn(uint32_t fn,
m_window.v_s(), mcs_name(new_cs));
bsn = create_new_bsn(fn, new_cs);
- } else if (!m_window.window_empty()) {
+ } else if (!m_window.window_empty() && bts->bts_data()->dl_tbf_preemptive_retransmission) {
LOGPTBFDL(this, LOGL_DEBUG,
"Restarting at BSN %d, because all blocks have been transmitted (FLOW).\n",
m_window.v_a());