documentation,bugfix - added documentation to new blocking queues, changed class names, and removed blocking pushes from the critical path

lib/include/srslte/adt/circular_buffer.h

@@ -39,6 +39,14 @@ size_t get_max_size(const std::vector<T>& a)
   return a.capacity();
 }
 
+/**
+ * Base common class for definition of circular buffer data structures with the following features:
+ * - no allocations while pushing/popping new elements. Just an internal index update
+ * - it provides helper methods to add/remove objects
+ * - it provides an iterator interface to iterate over added elements in the buffer
+ * - not thread-safe
+ * @tparam Container underlying container type used as buffer (e.g. std::array<T, N> or std::vector<T>)
+ */
 template <typename Container>
 class base_circular_buffer
 {
@@ -85,9 +93,16 @@ public:
   };
 
   template <typename... Args>
-  base_circular_buffer(Args&&... args) : buffer(std::forward<Args>(args)...)
+  explicit base_circular_buffer(Args&&... args) : buffer(std::forward<Args>(args)...)
   {}
 
+  bool try_push(T&& t)
+  {
+    if (full()) {
+      return false;
+    }
+    push(std::move(t));
+  }
   void push(T&& t)
   {
     assert(not full());
@@ -95,6 +110,13 @@ public:
     buffer[wpos] = std::move(t);
     count++;
   }
+  bool try_push(const T& t)
+  {
+    if (full()) {
+      return false;
+    }
+    push(t);
+  }
   void push(const T& t)
   {
     assert(not full());
@@ -148,17 +170,26 @@ struct noop_operator {
   }
 };
 
+/**
+ * Base common class for definition of blocking queue data structures with the following features:
+ * - it stores pushed/popped samples in an internal circular buffer
+ * - provides blocking and non-blocking push/pop APIs
+ * - thread-safe
+ * @tparam CircBuffer underlying circular buffer data type (e.g. static_circular_buffer<T, N> or dyn_circular_buffer<T>)
+ * @tparam PushingFunc function void(const T&) called while pushing an element to the queue
+ * @tparam PoppingFunc function void(const T&) called while popping an element from the queue
+ */
 template <typename CircBuffer, typename PushingFunc, typename PoppingFunc>
-class base_block_queue
+class base_blocking_queue
 {
   using T = typename CircBuffer::value_type;
 
 public:
   template <typename... Args>
-  base_block_queue(PushingFunc push_func_, PoppingFunc pop_func_, Args&&... args) :
+  base_blocking_queue(PushingFunc push_func_, PoppingFunc pop_func_, Args&&... args) :
     circ_buffer(std::forward<Args>(args)...), push_func(push_func_), pop_func(pop_func_)
   {}
-  ~base_block_queue() { stop(); }
+  ~base_blocking_queue() { stop(); }
 
   void stop()
   {
@@ -323,10 +354,24 @@ protected:
 
 } // namespace detail
 
+/**
+ * Circular buffer with fixed, embedded buffer storage via a std::array<T, N>.
+ * - Single allocation at object creation for std::array. Given that the buffer size is known at compile-time, the
+ *   circular iteration over the buffer may be more optimized (e.g. when N is a power of 2, % operator can be avoided)
+ * - not thread-safe
+ * @tparam T value type stored by buffer
+ * @tparam N size of the queue
+ */
 template <typename T, size_t N>
 class static_circular_buffer : public detail::base_circular_buffer<std::array<T, N> >
 {};
 
+/**
+ * Circular buffer with buffer storage via a std::vector<T>.
+ * - size can be defined at run-time.
+ * - not thread-safe
+ * @tparam T value type stored by buffer
+ */
 template <typename T>
 class dyn_circular_buffer : public detail::base_circular_buffer<std::vector<T> >
 {
@@ -344,31 +389,52 @@ public:
   }
 };
 
+/**
+ * Blocking queue with fixed, embedded buffer storage via a std::array<T, N>.
+ * - Blocking push/pop API via push_blocking(...) and pop_blocking(...) methods
+ * - Non-blocking push/pop API via try_push(...) and try_pop(...) methods
+ * - Only one initial allocation for the std::array<T, N>
+ * - thread-safe
+ * @tparam T value type stored by buffer
+ * @tparam N size of queue
+ * @tparam PushingCallback function void(const T&) called while pushing an element to the queue
+ * @tparam PoppingCallback function void(const T&) called while popping an element from the queue
+ */
 template <typename T,
           size_t N,
           typename PushingCallback = detail::noop_operator,
           typename PoppingCallback = detail::noop_operator>
-class static_block_queue
-  : public detail::base_block_queue<static_circular_buffer<T, N>, PushingCallback, PoppingCallback>
+class static_blocking_queue
+  : public detail::base_blocking_queue<static_circular_buffer<T, N>, PushingCallback, PoppingCallback>
 {
-  using base_t = detail::base_block_queue<static_circular_buffer<T, N>, PushingCallback, PoppingCallback>;
+  using base_t = detail::base_blocking_queue<static_circular_buffer<T, N>, PushingCallback, PoppingCallback>;
 
 public:
-  explicit static_block_queue(PushingCallback push_callback = {}, PoppingCallback pop_callback = {}) :
+  explicit static_blocking_queue(PushingCallback push_callback = {}, PoppingCallback pop_callback = {}) :
     base_t(push_callback, pop_callback)
   {}
 };
 
+/**
+ * Blocking queue with buffer storage represented via a std::vector<T>. Features:
+ * - Blocking push/pop API via push_blocking(...) and pop_blocking(...) methods
+ * - Non-blocking push/pop API via try_push(...) and try_pop(...) methods
+ * - Size can be defined at runtime.
+ * - thread-safe
+ * @tparam T value type stored by buffer
+ * @tparam PushingCallback function void(const T&) called while pushing an element to the queue
+ * @tparam PoppingCallback function void(const T&) called while popping an element from the queue
+ */
 template <typename T,
           typename PushingCallback = detail::noop_operator,
           typename PoppingCallback = detail::noop_operator>
-class dyn_block_queue : public detail::base_block_queue<dyn_circular_buffer<T>, PushingCallback, PoppingCallback>
+class dyn_blocking_queue : public detail::base_blocking_queue<dyn_circular_buffer<T>, PushingCallback, PoppingCallback>
 {
-  using base_t = detail::base_block_queue<dyn_circular_buffer<T>, PushingCallback, PoppingCallback>;
+  using base_t = detail::base_blocking_queue<dyn_circular_buffer<T>, PushingCallback, PoppingCallback>;
 
 public:
-  dyn_block_queue() = default;
-  explicit dyn_block_queue(size_t size, PushingCallback push_callback = {}, PoppingCallback pop_callback = {}) :
+  dyn_blocking_queue() = default;
+  explicit dyn_blocking_queue(size_t size, PushingCallback push_callback = {}, PoppingCallback pop_callback = {}) :
     base_t(push_callback, pop_callback, size)
   {}
   void set_size(size_t size) { base_t::circ_buffer.set_size(size); }

lib/include/srslte/common/mac_pcap_base.h

@@ -96,7 +96,7 @@ protected:
   std::mutex                             mutex;
   srslog::basic_logger&                  logger;
   bool                                   running = false;
-  static_block_queue<pcap_pdu_t, 256> queue;
+  static_blocking_queue<pcap_pdu_t, 256> queue;
   uint16_t                               ue_id = 0;
 
 private:

lib/include/srslte/mac/pdu_queue.h

@@ -61,7 +61,7 @@ private:
 
   } pdu_t;
 
-  dyn_block_queue<pdu_t*> pdu_q;
+  dyn_blocking_queue<pdu_t*> pdu_q;
   buffer_pool<pdu_t>         pool;
 
   process_callback*     callback;

lib/include/srslte/upper/byte_buffer_queue.h

@@ -79,7 +79,7 @@ private:
     uint32_t* unread_bytes;
   };
 
-  dyn_block_queue<unique_byte_buffer_t, push_callback, pop_callback> queue;
+  dyn_blocking_queue<unique_byte_buffer_t, push_callback, pop_callback> queue;
   uint32_t                                                              unread_bytes = 0;
 };
 

lib/include/srslte/upper/rlc_common.h

@@ -303,8 +303,8 @@ private:
     uint32_t nof_bytes;
   } pdu_t;
 
-  static_block_queue<pdu_t, 256>                rx_pdu_resume_queue;
-  static_block_queue<unique_byte_buffer_t, 256> tx_sdu_resume_queue;
+  static_blocking_queue<pdu_t, 256>                rx_pdu_resume_queue;
+  static_blocking_queue<unique_byte_buffer_t, 256> tx_sdu_resume_queue;
 };
 
 } // namespace srslte

lib/src/common/mac_pcap_base.cc

@@ -84,7 +84,9 @@ void mac_pcap_base::pack_and_queue(uint8_t* payload,
       // copy payload into PDU buffer
       memcpy(pdu.pdu->msg, payload, payload_len);
       pdu.pdu->N_bytes = payload_len;
-      queue.push_blocking(std::move(pdu));
+      if (not queue.try_push(std::move(pdu))) {
+        logger.error("Failed to push message to pcap writer queue");
+      }
     } else {
       logger.info("Dropping PDU in PCAP. No buffer available or not enough space (pdu_len=%d).", payload_len);
     }
@@ -119,7 +121,9 @@ void mac_pcap_base::pack_and_queue_nr(uint8_t* payload,
       // copy payload into PDU buffer
       memcpy(pdu.pdu->msg, payload, payload_len);
       pdu.pdu->N_bytes = payload_len;
-      queue.push_blocking(std::move(pdu));
+      if (not queue.try_push(std::move(pdu))) {
+        logger.error("Failed to push message to pcap writer queue");
+      }
     } else {
       logger.info("Dropping PDU in NR PCAP. No buffer available or not enough space (pdu_len=%d).", payload_len);
     }

lib/test/adt/circular_buffer_test.cc

@@ -66,7 +66,7 @@ int test_static_circular_buffer()
 
 int test_queue_block_api()
 {
-  dyn_block_queue<int> queue(100);
+  dyn_blocking_queue<int> queue(100);
 
   std::thread t([&queue]() {
     int count = 0;
@@ -94,7 +94,7 @@ int test_queue_block_api_2()
   std::thread t;
 
   {
-    dyn_block_queue<int> queue(100);
+    dyn_blocking_queue<int> queue(100);
 
     t = std::thread([&queue]() {
       int count = 0;

srsenb/hdr/stack/enb_stack_lte.h

@@ -162,7 +162,7 @@ private:
   // state
   bool started = false;
 
-  srslte::dyn_block_queue<stack_metrics_t> pending_stack_metrics;
+  srslte::dyn_blocking_queue<stack_metrics_t> pending_stack_metrics;
 };
 
 } // namespace srsenb

srsenb/hdr/stack/mac/mac.h

@@ -140,7 +140,7 @@ private:
   std::map<uint16_t, std::unique_ptr<ue> > ue_db, ues_to_rem;
   uint16_t                                 last_rnti = 70;
 
-  srslte::static_block_queue<std::unique_ptr<ue>, 32> ue_pool; ///< Pool of pre-allocated UE objects
+  srslte::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,

srsenb/hdr/stack/rrc/rrc.h

@@ -190,7 +190,7 @@ private:
   const static uint32_t LCID_RTX_USER = 0xffff0005;
 
   bool                                running = false;
-  srslte::dyn_block_queue<rrc_pdu> rx_pdu_queue;
+  srslte::dyn_blocking_queue<rrc_pdu> rx_pdu_queue;
 
   asn1::rrc::mcch_msg_s  mcch;
   bool                   enable_mbms     = false;