Review at https://gerrit.osmocom.org/3930
Simplify TS alloc: split USF/UL allocation
* move USF allocation into separate function
* document USF allocation
This allows to clearly see where selected UL TS is forced into single TS
in algorithm B allocator.
Change-Id: I563dc10827ce68295553f88f3bf2e1fc0ba595c1
Related: OS#2282
---
M src/gprs_rlcmac_ts_alloc.cpp
1 file changed, 42 insertions(+), 20 deletions(-)
git pull ssh://gerrit.osmocom.org:29418/osmo-pcu refs/changes/30/3930/1
diff --git a/src/gprs_rlcmac_ts_alloc.cpp b/src/gprs_rlcmac_ts_alloc.cpp
index cfef05a..6dfb13b 100644
--- a/src/gprs_rlcmac_ts_alloc.cpp
+++ b/src/gprs_rlcmac_ts_alloc.cpp
@@ -950,6 +950,44 @@
return sl;
}
+/*! Allocate USF according to a given UL TS mapping
+ *
+ * N. B: this is legacy implementation which ignores given selected_ul_slots
+ * \param[in] trx Pointer to TRX object
+ * \param[in] tbf Pointer to TBF object
+ * \param[in] first_common_ts First TS which is common to both UL and DL
+ * \param[in] selected_ul_slots set of UL timeslots selected for allocation
+ * \param[in] dl_slots set of DL timeslots
+ * \param[out] usf array for allocated USF
+ * \returns updated UL TS or negative on error
+ */
+static int allocate_usf(const gprs_rlcmac_trx *trx, int8_t first_common_ts,
uint8_t selected_ul_slots, uint8_t dl_slots,
+ int *usf)
+{
+ int free_usf = -1, ts;
+ uint8_t ul_slots = selected_ul_slots;
+
+ if (first_common_ts >= 0)
+ ul_slots = 1 << first_common_ts;
+ else
+ ul_slots = ul_slots & dl_slots;
+
+ ts = find_least_busy_pdch(trx, GPRS_RLCMAC_UL_TBF, ul_slots,
compute_usage_by_num_tbfs, NULL, &free_usf);
+
+ if (free_usf < 0 || ts < 0) {
+ LOGP(DRLCMAC, LOGL_NOTICE, "No USF available\n");
+ return -EBUSY;
+ }
+
+ OSMO_ASSERT(ts >= 0 && ts <= 8);
+
+ /* We will stick to that single UL slot, unreserve the others */
+ ul_slots = 1 << ts;
+ usf[ts] = free_usf;
+
+ return ul_slots;
+}
+
/*! Slot Allocation: Algorithm B
*
* Assign as many downlink slots as possible.
@@ -973,7 +1011,6 @@
int8_t first_common_ts;
uint8_t slotcount = 0;
uint8_t avail_count = 0, trx_no;
- int ts;
int first_ts = -1;
int usf[8] = {-1, -1, -1, -1, -1, -1, -1, -1};
int rc;
@@ -1027,27 +1064,12 @@
dl_slots = rc;
update_slot_counters(dl_slots, reserved_dl_slots, &slotcount,
&avail_count);
} else {
- int free_usf = -1;
-
- ul_slots = rc;
-
- if (first_common_ts >= 0)
- ul_slots = 1 << first_common_ts;
- else
- ul_slots = ul_slots & dl_slots;
-
- ts = find_least_busy_pdch(trx, GPRS_RLCMAC_UL_TBF, ul_slots,
compute_usage_by_num_tbfs, NULL, &free_usf);
-
- if (free_usf < 0) {
- LOGP(DRLCMAC, LOGL_NOTICE, "No USF available\n");
- return -EBUSY;
- }
-
- OSMO_ASSERT(ts >= 0 && ts <= 8);
+ rc = allocate_usf(trx, first_common_ts, rc, dl_slots, usf);
+ if (rc < 0)
+ return rc;
/* We will stick to that single UL slot, unreserve the others */
- ul_slots = 1 << ts;
- usf[ts] = free_usf;
+ ul_slots = rc;
reserved_ul_slots = ul_slots;
update_slot_counters(ul_slots, reserved_ul_slots, &slotcount,
&avail_count);
--
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Gerrit-MessageType: newchange
Gerrit-Change-Id: I563dc10827ce68295553f88f3bf2e1fc0ba595c1
Gerrit-PatchSet: 1
Gerrit-Project: osmo-pcu
Gerrit-Branch: master
Gerrit-Owner: Max <msur...@sysmocom.de>
