mac,optimization: use rnti memory pool to create mac::ue objects

lib/include/srsran/interfaces/enb_mac_interfaces.h

@@ -210,7 +210,6 @@ class mac_interface_rrc
 public:
   /* Provides cell configuration including SIB periodicity, etc. */
   virtual int cell_cfg(const std::vector<sched_interface::cell_cfg_t>& cell_cfg) = 0;
-  virtual void reset()                                                            = 0;
 
   /* Manages UE configuration context */
   virtual int ue_cfg(uint16_t rnti, sched_interface::ue_cfg_t* cfg) = 0;

srsenb/hdr/stack/mac/mac.h

@@ -14,6 +14,7 @@
 #define SRSENB_MAC_H
 
 #include "sched.h"
+#include "srsenb/hdr/common/rnti_pool.h"
 #include "srsenb/hdr/stack/mac/schedulers/sched_time_rr.h"
 #include "srsran/adt/circular_map.h"
 #include "srsran/adt/pool/batch_mem_pool.h"
@@ -74,7 +75,6 @@ public:
   /******** Interface from RRC (RRC -> MAC) ****************/
   /* Provides cell configuration including SIB periodicity, etc. */
   int cell_cfg(const std::vector<sched_interface::cell_cfg_t>& cell_cfg) override;
-  void reset() override;
 
   /* Manages UE scheduling context */
   int ue_cfg(uint16_t rnti, sched_interface::ue_cfg_t* cfg) override;
@@ -107,11 +107,9 @@ public:
 private:
   static const uint32_t cfi = 3;
 
-  bool     check_ue_exists(uint16_t rnti);
+  bool     check_ue_active(uint16_t rnti);
-  uint16_t allocate_rnti();
   uint16_t allocate_ue();
-
+  bool     is_valid_rnti_unprotected(uint16_t rnti);
-  std::mutex rnti_mutex;
 
   srslog::basic_logger& logger;
 
@@ -140,12 +138,9 @@ private:
   sched_interface::dl_pdu_mch_t mch = {};
 
   /* Map of active UEs */
-  rnti_map_t<std::unique_ptr<ue> >         ue_db;
+  static const uint16_t            FIRST_RNTI = 0x46;
-  std::map<uint16_t, std::unique_ptr<ue> > ues_to_rem;
+  rnti_map_t<unique_rnti_ptr<ue> > ue_db;
-  uint16_t                                 last_rnti = 70;
+  std::atomic<uint16_t>            ue_counter;
-
-  srsran::static_blocking_queue<std::unique_ptr<ue>, 32> ue_pool; ///< Pool of pre-allocated UE objects
-  void                                                   prealloc_ue(uint32_t nof_ue);
 
   uint8_t* assemble_rar(sched_interface::dl_sched_rar_grant_t* grants,
                         uint32_t                               enb_cc_idx,

srsenb/hdr/stack/mac/ue.h

@@ -142,6 +142,8 @@ public:
   uint32_t set_ta_us(float ta_us) { return ta_fsm.push_value(ta_us); };
   void     tic();
   void     trigger_padding(int lcid);
+  void     set_active(bool active) { active_state.store(active, std::memory_order_relaxed); }
+  bool     is_active() const { return active_state.load(std::memory_order_relaxed); }
 
   uint8_t* generate_pdu(uint32_t                              ue_cc_idx,
                         uint32_t                              harq_pid,
@@ -189,6 +191,8 @@ private:
   uint32_t              last_tti     = 0;
   uint32_t              nof_failures = 0;
 
+  std::atomic<bool> active_state{true};
+
   uint32_t         phr_counter    = 0;
   uint32_t         dl_cqi_counter = 0;
   uint32_t         dl_ri_counter  = 0;

srsenb/src/stack/mac/mac.cc

@@ -48,10 +48,6 @@ bool mac::init(const mac_args_t&        args_,
                rrc_interface_mac*       rrc)
 {
   started = false;
-
-  if (not phy or not rlc) {
-    return false;
-  }
   phy_h   = phy;
   rlc_h   = rlc;
   rrc_h   = rrc;
@@ -74,8 +70,6 @@ bool mac::init(const mac_args_t&        args_,
     srsran_softbuffer_tx_init(&cc.rar_softbuffer_tx, args.nof_prb);
   }
 
-  reset();
-
   // Initiate common pool of softbuffers
   uint32_t nof_prb          = args.nof_prb;
   auto     init_softbuffers = [nof_prb](void* ptr) {
@@ -85,9 +79,6 @@ bool mac::init(const mac_args_t&        args_,
   softbuffer_pool.reset(new srsran::background_obj_pool<ue_cc_softbuffers>(
       8, 8, args.nof_prealloc_ues, init_softbuffers, recycle_softbuffers));
 
-  // Pre-alloc UE objects for first attaching users
-  prealloc_ue(10);
-
   detected_rachs.resize(cells.size());
 
   started = true;
@@ -108,21 +99,9 @@ void mac::stop()
       srsran_softbuffer_tx_free(&cc.pcch_softbuffer_tx);
       srsran_softbuffer_tx_free(&cc.rar_softbuffer_tx);
     }
-    ue_pool.stop();
   }
 }
 
-// Implement Section 5.9
-void mac::reset()
-{
-  logger.info("Resetting MAC");
-
-  last_rnti = 70;
-
-  /* Setup scheduler */
-  scheduler.reset();
-}
-
 void mac::start_pcap(srsran::mac_pcap* pcap_)
 {
   srsran::rwlock_read_guard lock(rwlock);
@@ -148,11 +127,12 @@ void mac::start_pcap_net(srsran::mac_pcap_net* pcap_net_)
  * RLC interface
  *
  *******************************************************/
+
 int mac::rlc_buffer_state(uint16_t rnti, uint32_t lc_id, uint32_t tx_queue, uint32_t retx_queue)
 {
   srsran::rwlock_read_guard lock(rwlock);
   int                       ret = -1;
-  if (ue_db.contains(rnti)) {
+  if (check_ue_active(rnti)) {
     if (rnti != SRSRAN_MRNTI) {
       ret = scheduler.dl_rlc_buffer_state(rnti, lc_id, tx_queue, retx_queue);
     } else {
@@ -163,34 +143,20 @@ int mac::rlc_buffer_state(uint16_t rnti, uint32_t lc_id, uint32_t tx_queue, uint
       }
       ret = 0;
     }
-  } else {
-    logger.error("User rnti=0x%x not found", rnti);
   }
   return ret;
 }
 
 int mac::bearer_ue_cfg(uint16_t rnti, uint32_t lc_id, sched_interface::ue_bearer_cfg_t* cfg)
 {
-  int                       ret = -1;
   srsran::rwlock_read_guard lock(rwlock);
-  if (ue_db.contains(rnti)) {
+  return check_ue_active(rnti) ? scheduler.bearer_ue_cfg(rnti, lc_id, *cfg) : -1;
-    ret = scheduler.bearer_ue_cfg(rnti, lc_id, *cfg);
-  } else {
-    logger.error("User rnti=0x%x not found", rnti);
-  }
-  return ret;
 }
 
 int mac::bearer_ue_rem(uint16_t rnti, uint32_t lc_id)
 {
   srsran::rwlock_read_guard lock(rwlock);
-  int                       ret = -1;
+  return check_ue_active(rnti) ? scheduler.bearer_ue_rem(rnti, lc_id) : -1;
-  if (ue_db.contains(rnti)) {
-    ret = scheduler.bearer_ue_rem(rnti, lc_id);
-  } else {
-    logger.error("User rnti=0x%x not found", rnti);
-  }
-  return ret;
 }
 
 void mac::phy_config_enabled(uint16_t rnti, bool enabled)
@@ -202,14 +168,10 @@ void mac::phy_config_enabled(uint16_t rnti, bool enabled)
 int mac::ue_cfg(uint16_t rnti, sched_interface::ue_cfg_t* cfg)
 {
   srsran::rwlock_read_guard lock(rwlock);
-
+  if (not check_ue_active(rnti)) {
-  auto it     = ue_db.find(rnti);
-  ue*  ue_ptr = nullptr;
-  if (it == ue_db.end()) {
-    logger.error("User rnti=0x%x not found", rnti);
     return SRSRAN_ERROR;
   }
-  ue_ptr = it->second.get();
+  ue* ue_ptr = ue_db[rnti].get();
 
   // Start TA FSM in UE entity
   ue_ptr->start_ta();
@@ -227,10 +189,9 @@ int mac::ue_rem(uint16_t rnti)
 {
   // Remove UE from the perspective of L2/L3
   {
-    srsran::rwlock_write_guard lock(rwlock);
+    srsran::rwlock_read_guard lock(rwlock);
-    if (ue_db.contains(rnti)) {
+    if (check_ue_active(rnti)) {
-      ues_to_rem[rnti] = std::move(ue_db[rnti]);
+      ue_db[rnti]->set_active(false);
-      ue_db.erase(rnti);
     } else {
       logger.error("User rnti=0x%x not found", rnti);
       return SRSRAN_ERROR;
@@ -242,7 +203,8 @@ int mac::ue_rem(uint16_t rnti)
   // Note: Let any pending retx ACK to arrive, so that PHY recognizes rnti
   task_sched.defer_callback(FDD_HARQ_DELAY_DL_MS + FDD_HARQ_DELAY_UL_MS, [this, rnti]() {
     phy_h->rem_rnti(rnti);
-    ues_to_rem.erase(rnti);
+    srsran::rwlock_write_guard lock(rwlock);
+    ue_db.erase(rnti);
     logger.info("User rnti=0x%x removed from MAC/PHY", rnti);
   });
   return SRSRAN_SUCCESS;
@@ -259,11 +221,7 @@ int mac::ue_set_crnti(uint16_t temp_crnti, uint16_t crnti, sched_interface::ue_c
     // Schedule ConRes Msg4
     scheduler.dl_mac_buffer_state(crnti, (uint32_t)srsran::dl_sch_lcid::CON_RES_ID);
   }
-  int ret = ue_cfg(crnti, cfg);
+  return ue_cfg(crnti, cfg);
-  if (ret != SRSRAN_SUCCESS) {
-    return ret;
-  }
-  return ret;
 }
 
 int mac::cell_cfg(const std::vector<sched_interface::cell_cfg_t>& cell_cfg_)
@@ -313,7 +271,7 @@ int mac::ack_info(uint32_t tti_rx, uint16_t rnti, uint32_t enb_cc_idx, uint32_t
   logger.set_context(tti_rx);
   srsran::rwlock_read_guard lock(rwlock);
 
-  if (not check_ue_exists(rnti)) {
+  if (not check_ue_active(rnti)) {
     return SRSRAN_ERROR;
   }
 
@@ -330,7 +288,7 @@ int mac::crc_info(uint32_t tti_rx, uint16_t rnti, uint32_t enb_cc_idx, uint32_t
   logger.set_context(tti_rx);
   srsran::rwlock_read_guard lock(rwlock);
 
-  if (not check_ue_exists(rnti)) {
+  if (not check_ue_active(rnti)) {
     return SRSRAN_ERROR;
   }
 
@@ -352,7 +310,7 @@ int mac::push_pdu(uint32_t tti_rx,
 {
   srsran::rwlock_read_guard lock(rwlock);
 
-  if (not check_ue_exists(rnti)) {
+  if (not check_ue_active(rnti)) {
     return SRSRAN_ERROR;
   }
 
@@ -380,8 +338,10 @@ int mac::push_pdu(uint32_t tti_rx,
                   (int)pdu->size());
     auto process_pdu_task = [this, rnti, ul_nof_prbs](srsran::unique_byte_buffer_t& pdu) {
       srsran::rwlock_read_guard lock(rwlock);
-      if (ue_db.contains(rnti)) {
+      if (check_ue_active(rnti)) {
         ue_db[rnti]->process_pdu(std::move(pdu), ul_nof_prbs);
+      } else {
+        logger.debug("Discarding PDU rnti=0x%x", rnti);
       }
     };
     auto ret = stack_task_queue.try_push(std::bind(process_pdu_task, std::move(pdu)));
@@ -396,7 +356,7 @@ int mac::ri_info(uint32_t tti, uint16_t rnti, uint32_t enb_cc_idx, uint32_t ri_v
   logger.set_context(tti);
   srsran::rwlock_read_guard lock(rwlock);
 
-  if (not check_ue_exists(rnti)) {
+  if (not check_ue_active(rnti)) {
     return SRSRAN_ERROR;
   }
 
@@ -411,7 +371,7 @@ int mac::pmi_info(uint32_t tti, uint16_t rnti, uint32_t enb_cc_idx, uint32_t pmi
   logger.set_context(tti);
   srsran::rwlock_read_guard lock(rwlock);
 
-  if (not check_ue_exists(rnti)) {
+  if (not check_ue_active(rnti)) {
     return SRSRAN_ERROR;
   }
 
@@ -426,7 +386,7 @@ int mac::cqi_info(uint32_t tti, uint16_t rnti, uint32_t enb_cc_idx, uint32_t cqi
   logger.set_context(tti);
   srsran::rwlock_read_guard lock(rwlock);
 
-  if (not check_ue_exists(rnti)) {
+  if (not check_ue_active(rnti)) {
     return SRSRAN_ERROR;
   }
 
@@ -441,7 +401,7 @@ int mac::snr_info(uint32_t tti_rx, uint16_t rnti, uint32_t enb_cc_idx, float snr
   logger.set_context(tti_rx);
   srsran::rwlock_read_guard lock(rwlock);
 
-  if (not check_ue_exists(rnti)) {
+  if (not check_ue_active(rnti)) {
     return SRSRAN_ERROR;
   }
 
@@ -454,13 +414,13 @@ int mac::ta_info(uint32_t tti, uint16_t rnti, float ta_us)
 {
   srsran::rwlock_read_guard lock(rwlock);
 
-  if (not check_ue_exists(rnti)) {
+  if (not check_ue_active(rnti)) {
     return SRSRAN_ERROR;
   }
 
   uint32_t nof_ta_count = ue_db[rnti]->set_ta_us(ta_us);
-  if (nof_ta_count) {
+  if (nof_ta_count > 0) {
-    scheduler.dl_mac_buffer_state(rnti, (uint32_t)srsran::dl_sch_lcid::TA_CMD, nof_ta_count);
+    return scheduler.dl_mac_buffer_state(rnti, (uint32_t)srsran::dl_sch_lcid::TA_CMD, nof_ta_count);
   }
   return SRSRAN_SUCCESS;
 }
@@ -470,65 +430,64 @@ int mac::sr_detected(uint32_t tti, uint16_t rnti)
   logger.set_context(tti);
   srsran::rwlock_read_guard lock(rwlock);
 
-  if (not check_ue_exists(rnti)) {
+  if (not check_ue_active(rnti)) {
     return SRSRAN_ERROR;
   }
 
   return scheduler.ul_sr_info(tti, rnti);
 }
 
-uint16_t mac::allocate_rnti()
+bool mac::is_valid_rnti_unprotected(uint16_t rnti)
 {
-  std::lock_guard<std::mutex> lock(rnti_mutex);
+  if (not started) {
-
+    logger.info("RACH ignored as eNB is being shutdown");
-  // Assign a c-rnti
+    return false;
-  uint16_t rnti = last_rnti++;
-  if (last_rnti >= 60000) {
-    last_rnti = 70;
   }
-
+  if (ue_db.full()) {
-  return rnti;
+    logger.warning("Maximum number of connected UEs %zd connected to the eNB. Ignoring PRACH", SRSENB_MAX_UES);
+    return false;
+  }
+  if (not ue_db.has_space(rnti)) {
+    logger.info("Failed to allocate rnti=0x%x. Attempting a different rnti.", rnti);
+    return false;
+  }
+  return true;
 }
 
 uint16_t mac::allocate_ue()
 {
   ue*      inserted_ue = nullptr;
+  uint16_t rnti        = SRSRAN_INVALID_RNTI;
+
   do {
-    // Get pre-allocated UE object
+    // Assign new RNTI
-    std::unique_ptr<ue> ue_ptr;
+    rnti = FIRST_RNTI + (ue_counter.fetch_add(1, std::memory_order_relaxed) % 60000);
-    if (not ue_pool.try_pop(ue_ptr)) {
-      logger.error("UE pool empty. Ignoring RACH attempt.");
-      return SRSRAN_INVALID_RNTI;
-    }
-    uint16_t rnti = ue_ptr->get_rnti();
 
-    // Add UE to map
+    // Pre-check if rnti is valid
     {
-      srsran::rwlock_write_guard lock(rwlock);
+      srsran::rwlock_read_guard read_lock(rwlock);
-      if (not started) {
+      if (not is_valid_rnti_unprotected(rnti)) {
-        logger.info("RACH ignored as eNB is being shutdown");
+        continue;
-        return SRSRAN_INVALID_RNTI;
       }
-      if (ue_db.size() >= SRSENB_MAX_UES) {
+    }
-        logger.warning("Maximum number of connected UEs %zd connected to the eNB. Ignoring PRACH", SRSENB_MAX_UES);
+
-        return SRSRAN_INVALID_RNTI;
+    // Allocate and initialize UE object
+    unique_rnti_ptr<ue> ue_ptr = make_rnti_obj<ue>(
+        rnti, rnti, args.nof_prb, &scheduler, rrc_h, rlc_h, phy_h, logger, cells.size(), softbuffer_pool.get());
+
+    // Add UE to rnti map
+    srsran::rwlock_write_guard rw_lock(rwlock);
+    if (not is_valid_rnti_unprotected(rnti)) {
+      continue;
     }
     auto ret = ue_db.insert(rnti, std::move(ue_ptr));
-      if (ret) {
+    if (ret.has_value()) {
       inserted_ue = ret.value()->second.get();
     } else {
       logger.info("Failed to allocate rnti=0x%x. Attempting a different rnti.", rnti);
     }
-    }
-
-    // Allocate one new UE object in advance
-    srsran::get_background_workers().push_task([this]() { prealloc_ue(1); });
-
   } while (inserted_ue == nullptr);
 
-  // RNTI allocation was successful
-  uint16_t rnti = inserted_ue->get_rnti();
-
   // Set PCAP if available
   if (pcap != nullptr) {
     inserted_ue->start_pcap(pcap);
@@ -614,18 +573,6 @@ void mac::rach_detected(uint32_t tti, uint32_t enb_cc_idx, uint32_t preamble_idx
   });
 }
 
-void mac::prealloc_ue(uint32_t nof_ue)
-{
-  for (uint32_t i = 0; i < nof_ue; i++) {
-    std::unique_ptr<ue> ptr = std::unique_ptr<ue>(new ue(
-        allocate_rnti(), args.nof_prb, &scheduler, rrc_h, rlc_h, phy_h, logger, cells.size(), softbuffer_pool.get()));
-    if (not ue_pool.try_push(std::move(ptr))) {
-      logger.info("Cannot preallocate more UEs as pool is full");
-      return;
-    }
-  }
-}
-
 int mac::get_dl_sched(uint32_t tti_tx_dl, dl_sched_list_t& dl_sched_res_list)
 {
   if (!started) {
@@ -1045,15 +992,13 @@ void mac::write_mcch(const srsran::sib2_mbms_t* sib2_,
 }
 
 // Internal helper function, caller must hold UE DB rwlock
-bool mac::check_ue_exists(uint16_t rnti)
+bool mac::check_ue_active(uint16_t rnti)
 {
   if (not ue_db.contains(rnti)) {
-    if (not ues_to_rem.count(rnti)) {
     logger.error("User rnti=0x%x not found", rnti);
-    }
     return false;
   }
-  return true;
+  return ue_db[rnti]->is_active();
 }
 
 } // namespace srsenb

srsenb/test/common/dummy_classes.h

@@ -28,7 +28,6 @@ class mac_dummy : public mac_interface_rrc
 {
 public:
   int  cell_cfg(const std::vector<sched_interface::cell_cfg_t>& cell_cfg) override { return 0; }
-  void reset() override {}
   int  ue_cfg(uint16_t rnti, sched_interface::ue_cfg_t* cfg) override { return 0; }
   int  ue_rem(uint16_t rnti) override { return 0; }
   int  ue_set_crnti(uint16_t temp_crnti, uint16_t crnti, sched_interface::ue_cfg_t* cfg) override { return 0; }