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authoraravind sirsikar <arvind.sirsikar@radisys.com>2016-12-30 12:24:38 +0530
committeraravind sirsikar <arvind.sirsikar@radisys.com>2016-12-30 12:24:38 +0530
commit9ddc3c7845b094911b3eba1d17e6a74d7e7503ee (patch)
tree035d753a3f4770dbc6c7a2ffb551fae78d27276b /src/bts.cpp
parentd3ae14c18f44d24c0a5c592fa9bdc9350b90cfd3 (diff)
PDCH allocation across two TRXradisys/egprs_features
Implementation: PCU keeps track of number PDCH across all the TRXs at BTS context and also keeps number of active PDCHs in each TRX context. This ratio gives the CAPACITY of each TRX. 1st Phase: While selection of TRX, functions get_possible_trxs(for multiple TS) and get_possible_trxs_sba(Single block allocation, Ex: during RACH) gets possible TRXs based on TFIs availability. 2nd Phase: outcome of TRXs(from get_possible_trxs, get_possible_trxs_sba) will be fed to get_suitable_trx function. Which does actual load balancing on each TRX. And selects the best fit TRX, based on below equation PROBABILITY = MAX_PROBABILITY – ((LOAD * 100)/CAPACITY); If same PROBABILITY Select the one with higher capacity Else Find the TRX with higher PROBABILITY MAX_PROBABILITY = 65535; LOAD: Initialized to 0, Later gets incremented with number of TS allocated. and decremented whle TBF deletion, based on number of TS allocated Below are the test executed on Unit test environment 1) 2 TRXs, with same Capacity 2) 2 TRX with ½ capacity 3) 2 TRXs with ¼ capacity 4) 2 TRX with UL and DL allocation to ensure Tbfs on both direction is hosted on same TRX 5) 2 TRX with same Capacity and DL TBF creation and deletion scenarios to ensure proper load balancing criteria for actual Load. Below are the Test executed on Integration setup with Ettus B200 setup with 2 TRXs with same CAPACITY. 1) TRX allocation during RACH procedure(SBA allocation) 2) TRX allocation during DL TBF creation with multi time slots(4 time slots) 3) TRX allocation while Ping Test 4) TRX allocation while UDP test 5) TRX allocation for web browsing. 6) 2 MS test with each TRX sharing 1 MS. Received aggregate throughput of 446 kbps(223 Kbps each) Limitation: 1) BSSGP flow control needs to be tuned since test with 2 MS with each MS on different TRX runs for 20 mins 2) USF resource availibility is not checked while selecting the TRX as existing implementation Change-Id: Ifb61a7862d55af828383b6dfe728628e546ed12b Related: OS# 1775
Diffstat (limited to 'src/bts.cpp')
-rw-r--r--src/bts.cpp158
1 files changed, 142 insertions, 16 deletions
diff --git a/src/bts.cpp b/src/bts.cpp
index cfccec9..c116eed 100644
--- a/src/bts.cpp
+++ b/src/bts.cpp
@@ -188,11 +188,13 @@ BTS::BTS()
{
memset(&m_bts, 0, sizeof(m_bts));
m_bts.bts = this;
-
+ m_total_pdch = 0;
/* initialize back pointers */
for (size_t trx_no = 0; trx_no < ARRAY_SIZE(m_bts.trx); ++trx_no) {
struct gprs_rlcmac_trx *trx = &m_bts.trx[trx_no];
trx->trx_no = trx_no;
+ trx->num_pdch = 0;
+ trx->current_load = 0;
trx->bts = this;
for (size_t ts_no = 0; ts_no < ARRAY_SIZE(trx->pdch); ++ts_no) {
@@ -417,9 +419,82 @@ int BTS::tfi_find_free(enum gprs_rlcmac_tbf_direction dir,
uint8_t *_trx, int8_t use_trx)
{
struct gprs_rlcmac_pdch *pdch;
+ uint32_t free_tfis = 0xffffffff;
+ uint8_t ts, tfi;
+ bool possible_trx[8];
+ int ret;
+
+ /* This function will get list of possible TRXs */
+ ret = get_possible_trxs(dir, possible_trx, use_trx);
+ if (ret < 0)
+ return -EBUSY;
+
+
+ if (use_trx >= 0)
+ *_trx = use_trx;
+ else
+ *_trx = get_suitable_trx(possible_trx);
+
+ LOGP(DRLCMAC, LOGL_DEBUG,
+ "Searching for first unallocated TFI: TRX=%d\n", *_trx);
+
+ for (ts = 0; ts < 8; ts++) {
+ pdch = &m_bts.trx[*_trx].pdch[ts];
+ free_tfis &= ~pdch->assigned_tfi(dir);
+ }
+ /* find the first */
+ for (tfi = 0; tfi < 32; tfi++) {
+ if (free_tfis & 1 << tfi)
+ break;
+ }
+
+ OSMO_ASSERT(tfi < 32);
+
+ LOGP(DRLCMAC, LOGL_DEBUG, " Found TFI=%d.\n", tfi);
+
+ return tfi;
+}
+
+/*
+ * Search for free TFI and return TFI, TRX.
+ * This method returns the first TFI that is currently not used in any PDCH of
+ * a TRX. The first TRX that contains such an TFI is returned. Negative values
+ * indicate errors.
+ */
+int BTS::get_possible_trxs_sba(
+ bool *_trx)
+{
+ uint8_t trx;
+ bool has_pdch = false;
+
+ for (trx = 0; trx < 8; trx++) {
+ if (bts_data()->trx[trx].num_pdch) {
+ _trx[trx] = true;
+ has_pdch = true;
+ LOGP(DRLCMAC, LOGL_DEBUG, " Valid TRX=%d.\n", trx);
+ } else {
+ _trx[trx] = false;
+ LOGP(DRLCMAC, LOGL_DEBUG, " Not valid TRX=%d.\n", trx);
+ }
+ }
+ if (has_pdch)
+ return 0;
+
+ return -EINVAL;
+}
+
+/*
+ * This method loops through all possible TRX and
+ * returns subset of possible TRXs based on availability.
+ */
+int BTS::get_possible_trxs(enum gprs_rlcmac_tbf_direction dir,
+ bool *_trx, int8_t use_trx)
+{
+ struct gprs_rlcmac_pdch *pdch;
uint32_t free_tfis;
+ uint32_t is_tfis_available = false;
bool has_pdch = false;
- uint8_t trx_from, trx_to, trx, ts, tfi;
+ uint8_t trx_from, trx_to, trx, ts;
if (use_trx >= 0 && use_trx < 8)
trx_from = trx_to = use_trx;
@@ -442,8 +517,12 @@ int BTS::tfi_find_free(enum gprs_rlcmac_tbf_direction dir,
trx_has_pdch = true;
has_pdch = true;
}
- if (trx_has_pdch && free_tfis)
- break;
+ if (trx_has_pdch && free_tfis) {
+ _trx[trx] = true;
+ is_tfis_available = true;
+ } else {
+ _trx[trx] = false;
+ }
free_tfis = 0;
}
@@ -452,26 +531,69 @@ int BTS::tfi_find_free(enum gprs_rlcmac_tbf_direction dir,
return -EINVAL;
}
- if (!free_tfis) {
+ if (!is_tfis_available) {
LOGP(DRLCMAC, LOGL_NOTICE, "No TFI available.\n");
return -EBUSY;
}
+ return 0;
+}
+/*
+ * This method loops through all subset of TRXs provided by
+ * get_possible_trxs and does the load balancing algorithm. and
+ * selects best TRX possible based on load and capacity
+ */
+int BTS::get_suitable_trx(bool *avail_trx)
+{
+ uint8_t trx_from, trx_to, trx;
+ uint32_t select_probability = 0;
+ uint32_t temp_probability = 0;
+ int selected_trx = -1;
+ bool is_better_trx = false;
- LOGP(DRLCMAC, LOGL_DEBUG,
- "Searching for first unallocated TFI: TRX=%d\n", trx);
+ trx_from = 0;
+ trx_to = 7;
- /* find the first */
- for (tfi = 0; tfi < 32; tfi++) {
- if (free_tfis & 1 << tfi)
- break;
- }
+ for (trx = trx_from; trx <= trx_to; trx++) {
+ /* Check if this TRX is in possible list */
+ if (!avail_trx[trx])
+ continue;
- OSMO_ASSERT(tfi < 32);
+ is_better_trx = false;
+
+ temp_probability = MAX_LOAD_PROBABILITY -
+ (get_num_pdch() * 100 *
+ m_bts.trx[trx].current_load)
+ / m_bts.trx[trx].num_pdch;
+
+ LOGP(DRLCMAC, LOGL_DEBUG, "trx(%d) cur load(%d)"
+ " numpdch(%d) prob1(%u) seleprob(%u)"
+ " btsnumpdch(%d)\n", trx,
+ m_bts.trx[trx].current_load,
+ m_bts.trx[trx].num_pdch,
+ temp_probability, select_probability,
+ get_num_pdch());
+
+ if (temp_probability >= select_probability) {
+ if (temp_probability > select_probability)
+ is_better_trx = true;
+ else if (temp_probability == select_probability)
+ if (selected_trx >= 0 || selected_trx < 8)
+ if (m_bts.trx[selected_trx].num_pdch
+ < m_bts.trx[trx].num_pdch)
+ is_better_trx = true;
+ }
+ if (is_better_trx) {
+ selected_trx = trx;
+ select_probability =
+ temp_probability;
+ LOGP(DRLCMAC, LOGL_DEBUG, "selected pro(%u)"
+ "selected_trx(%d)\n",
+ select_probability, selected_trx);
+ }
+ }
- LOGP(DRLCMAC, LOGL_DEBUG, " Found TFI=%d.\n", tfi);
- *_trx = trx;
- return tfi;
+ return selected_trx;
}
int BTS::rcv_imm_ass_cnf(const uint8_t *data, uint32_t fn)
@@ -783,13 +905,17 @@ void gprs_rlcmac_pdch::enable()
{
/* TODO: Check if there are still allocated resources.. */
INIT_LLIST_HEAD(&paging_list);
+ trx->num_pdch++;
m_is_enabled = 1;
+ bts()->increment_num_pdch();
}
void gprs_rlcmac_pdch::disable()
{
/* TODO.. kick free_resources once we know the TRX/TS we are on */
m_is_enabled = 0;
+ trx->num_pdch--;
+ bts()->decrement_num_pdch();
}
void gprs_rlcmac_pdch::free_resources()