[HICN-316] improve rtc for low rate streams

Signed-off-by: michele papalini <micpapal@cisco.com>
Change-Id: I29d9720450f8cee429eb02a494092f208c298355

4 files changed, 26 insertions, 107 deletions

diff --git a/libtransport/src/hicn/transport/interfaces/rtc_socket_producer.cc b/libtransport/src/hicn/transport/interfaces/rtc_socket_producer.cc
index 5667b0640..009db812f 100644
--- a/libtransport/src/hicn/transport/interfaces/rtc_socket_producer.cc
+++ b/libtransport/src/hicn/transport/interfaces/rtc_socket_producer.cc
@@ -32,8 +32,8 @@
 #define HICN_MAX_DATA_SEQ 0xefffffff
 
 //slow production rate param
-#define MIN_PRODUCTION_RATE 8000 // in bytes per sec. this value is computed
-                                 // through experiments
+#define MIN_PRODUCTION_RATE 10 // in pacekts per sec. this value is computed
+                               // through experiments
 #define LIFETIME_FRACTION 0.5
 
 // NACK HEADER
@@ -63,8 +63,7 @@ RTCProducerSocket::RTCProducerSocket(asio::io_service &io_service)
       bytesProductionRate_(INIT_PACKET_PRODUCTION_RATE * 1400),
       packetsProductionRate_(INIT_PACKET_PRODUCTION_RATE),
       perSecondFactor_(MILLI_IN_A_SEC / STATS_INTERVAL_DURATION),
-      timer_on_(false),
-      active_(false) {
+      timer_on_(false){
   lastStats_ = std::chrono::duration_cast<std::chrono::milliseconds>(
                    std::chrono::steady_clock::now().time_since_epoch())
                    .count();
@@ -82,8 +81,7 @@ RTCProducerSocket::RTCProducerSocket()
       bytesProductionRate_(INIT_PACKET_PRODUCTION_RATE * 1400),
       packetsProductionRate_(INIT_PACKET_PRODUCTION_RATE),
       perSecondFactor_(MILLI_IN_A_SEC / STATS_INTERVAL_DURATION),
-      timer_on_(false),
-      active_(false) {
+      timer_on_(false){
   lastStats_ = std::chrono::duration_cast<std::chrono::milliseconds>(
                    std::chrono::steady_clock::now().time_since_epoch())
                    .count();
@@ -143,12 +141,6 @@ void RTCProducerSocket::produce(std::unique_ptr<utils::MemBuf> &&buffer) {
                      std::chrono::steady_clock::now().time_since_epoch())
                      .count();
 
-  {
-    utils::SpinLock::Acquire locked(lock_);
-    active_ = true;
-    lastProduced_ = now;
-  }
-
   updateStats((uint32_t)(buffer_size + headerSize_ + TIMESTAMP_LEN), now);
 
   ContentObject content_object(flowName_.setSuffix(currentSeg_));
@@ -203,27 +195,14 @@ void RTCProducerSocket::onInterest(Interest::Ptr &&interest) {
                          std::chrono::steady_clock::now().time_since_epoch())
                          .count();
 
-  bool isActive;
-  {
-    utils::SpinLock::Acquire locked(lock_);
-    isActive = active_;
-    if (isActive) {
-      if ((now - lastProduced_) > INACTIVE_TIME) {
-        // socket is inactive
-        active_ = false;
-        isActive = false;
-      }
-    }
-  }
-
   if(interestSeg > HICN_MAX_DATA_SEQ){
-    sendNack(interestSeg, isActive);
+    sendNack(interestSeg);
     return;
   }
 
   // if the production rate is less than MIN_PRODUCTION_RATE we put the
   // interest in a queue, otherwise we handle it in the usual way
-  if(bytesProductionRate_ < MIN_PRODUCTION_RATE && interestSeg > currentSeg_){
+  if(packetsProductionRate_.load() < MIN_PRODUCTION_RATE && interestSeg >= currentSeg_){
 
     utils::SpinLock::Acquire locked(interests_cache_lock_);
 
@@ -276,18 +255,13 @@ void RTCProducerSocket::onInterest(Interest::Ptr &&interest) {
     return;
   }
 
-  if (TRANSPORT_EXPECT_FALSE(!isActive)) {
-    sendNack(interestSeg, false);
-    return;
-  }
-
   uint32_t max_gap = (uint32_t)floor(
       (double)((double)((double)lifetime * INTEREST_LIFETIME_REDUCTION_FACTOR /
                         1000.0) *
                (double)packetsProductionRate_.load()));
 
   if (interestSeg < currentSeg_ || interestSeg > (max_gap + currentSeg_)) {
-    sendNack(interestSeg, true);
+    sendNack(interestSeg);
   }
   // else drop packet
 }
@@ -312,7 +286,7 @@ void RTCProducerSocket::interestCacheTimer(){
     uint64_t expire = it_timers->first;
     if(expire <= now){
       uint32_t seq = it_timers->second;
-      sendNack(seq, active_);
+      sendNack(seq);
       //remove the interest from the other map
       seqs_map_.erase(seq);
       it_timers = timers_map_.erase(it_timers);
@@ -329,7 +303,7 @@ void RTCProducerSocket::interestCacheTimer(){
   }
 }
 
-void RTCProducerSocket::sendNack(uint32_t sequence, bool isActive) {
+void RTCProducerSocket::sendNack(uint32_t sequence) {
   auto nack_payload = utils::MemBuf::create(NACK_HEADER_SIZE);
   nack_payload->append(NACK_HEADER_SIZE);
   ContentObject nack;
@@ -340,11 +314,7 @@ void RTCProducerSocket::sendNack(uint32_t sequence, bool isActive) {
   uint32_t *payload_ptr = (uint32_t *)nack.getPayload()->data();
   *payload_ptr = currentSeg_;
 
-  if (isActive) {
-    *(++payload_ptr) = bytesProductionRate_;
-  } else {
-    *(++payload_ptr) = 0;
-  }
+  *(++payload_ptr) = bytesProductionRate_.load();
 
   nack.setLifetime(0);
   nack.setPathLabel(prodLabel_);
diff --git a/libtransport/src/hicn/transport/interfaces/rtc_socket_producer.h b/libtransport/src/hicn/transport/interfaces/rtc_socket_producer.h
index aa67f1a29..62aa7a296 100644
--- a/libtransport/src/hicn/transport/interfaces/rtc_socket_producer.h
+++ b/libtransport/src/hicn/transport/interfaces/rtc_socket_producer.h
@@ -41,7 +41,7 @@ class RTCProducerSocket : public ProducerSocket {
   void onInterest(Interest::Ptr &&interest) override;
 
  private:
-  void sendNack(uint32_t sequence, bool isActive);
+  void sendNack(uint32_t sequence);
   void updateStats(uint32_t packet_size, uint64_t now);
   void scheduleTimer(uint64_t wait);
   void interestCacheTimer();
@@ -52,7 +52,7 @@ class RTCProducerSocket : public ProducerSocket {
   Name flowName_;
   uint32_t producedBytes_;
   uint32_t producedPackets_;
-  uint32_t bytesProductionRate_;
+  std::atomic<uint32_t> bytesProductionRate_;
   std::atomic<uint32_t> packetsProductionRate_;
   uint32_t perSecondFactor_;
   uint64_t lastStats_;
@@ -70,10 +70,6 @@ class RTCProducerSocket : public ProducerSocket {
   bool timer_on_;
   std::unique_ptr<asio::steady_timer> interests_cache_timer_;
   utils::SpinLock interests_cache_lock_;
-
-  uint64_t lastProduced_;
-  bool active_;
-  utils::SpinLock lock_;
 };
 
 }  // namespace interface
diff --git a/libtransport/src/hicn/transport/protocols/rtc.cc b/libtransport/src/hicn/transport/protocols/rtc.cc
index 4104d8883..accd98495 100644
--- a/libtransport/src/hicn/transport/protocols/rtc.cc
+++ b/libtransport/src/hicn/transport/protocols/rtc.cc
@@ -31,10 +31,8 @@ RTCTransportProtocol::RTCTransportProtocol(
       inflightInterests_(1 << default_values::log_2_default_buffer_size),
       modMask_((1 << default_values::log_2_default_buffer_size) - 1) {
   icnet_socket->getSocketOption(PORTAL, portal_);
-  nack_timer_ = std::make_unique<asio::steady_timer>(portal_->getIoService());
   rtx_timer_ = std::make_unique<asio::steady_timer>(portal_->getIoService());
   probe_timer_ = std::make_unique<asio::steady_timer>(portal_->getIoService());
-  nack_timer_used_ = false;
   reset();
 }
 
@@ -92,7 +90,6 @@ void RTCTransportProtocol::reset() {
   highestReceived_ = 0;
   firstSequenceInRound_ = 0;
 
-  nack_timer_used_ = false;
   rtx_timer_used_ = false;
   for(int i = 0; i < (1 << default_values::log_2_default_buffer_size); i++){
     inflightInterests_[i] = {0};
@@ -673,36 +670,6 @@ void RTCTransportProtocol::onTimeout(Interest::Ptr &&interest) {
   scheduleNextInterests();
 }
 
-bool RTCTransportProtocol::checkIfProducerIsActive(
-    const ContentObject &content_object) {
-  uint32_t *payload = (uint32_t *)content_object.getPayload()->data();
-  uint32_t productionSeg = *payload;
-  uint32_t productionRate = *(++payload);
-
-  if (productionRate == 0) {
-    // the producer socket is not active
-    // in this case we consider only the first nack
-    if (nack_timer_used_) {
-      return false;
-    }
-
-    nack_timer_used_ = true;
-    // actualSegment_ should be the one in the nack, which will be the next in
-    // production
-    actualSegment_ = productionSeg;
-    // all the rest (win size should not change)
-    // we wait a bit before pull the socket again
-    nack_timer_->expires_from_now(std::chrono::milliseconds(500));
-    nack_timer_->async_wait([this](std::error_code ec) {
-      if (ec) return;
-      nack_timer_used_ = false;
-      scheduleNextInterests();
-    });
-    return false;
-  }
-  return true;
-}
-
 bool RTCTransportProtocol::onNack(const ContentObject &content_object, bool rtx) {
   uint32_t *payload = (uint32_t *)content_object.getPayload()->data();
   uint32_t productionSeg = *payload;
@@ -719,7 +686,7 @@ bool RTCTransportProtocol::onNack(const ContentObject &content_object, bool rtx)
 
   if (productionSeg > nackSegment) {
     // we are asking for stuff produced in the past
-    actualSegment_ = max(productionSeg + 1, actualSegment_) % HICN_MIN_PROBE_SEQ;
+    actualSegment_ = max(productionSeg, actualSegment_) % HICN_MIN_PROBE_SEQ;
 
     if(!rtx) {
       if (currentState_ == HICN_RTC_NORMAL_STATE) {
@@ -756,7 +723,11 @@ bool RTCTransportProtocol::onNack(const ContentObject &content_object, bool rtx)
         currentState_ = HICN_RTC_NORMAL_STATE;
       }
     }
-  }  // equal should not happen
+  } else {
+    //we are asking the right thing, but the producer is slow
+    //keep doing the same until the packet is produced
+    actualSegment_ = productionSeg % HICN_MIN_PROBE_SEQ;
+  }
 
   return old_nack;
 }
@@ -771,7 +742,6 @@ void RTCTransportProtocol::onContentObject(
   uint32_t payload_size = (uint32_t)payload->length();
   uint32_t segmentNumber = content_object->getName().getSuffix();
   uint32_t pkt = segmentNumber & modMask_;
-  bool schedule_next_interest = true;
 
   ConsumerContentObjectCallback *callback_content_object = nullptr;
   socket_->getSocketOption(ConsumerCallbacksOptions::CONTENT_OBJECT_INPUT,
@@ -802,25 +772,19 @@ void RTCTransportProtocol::onContentObject(
   }
 
   if (payload_size == HICN_NACK_HEADER_SIZE) {
-    schedule_next_interest = checkIfProducerIsActive(*content_object);
-
     if (inflightInterests_[pkt].state == sent_) {
       inflightInterestsCount_--;
     }
 
-    // if checkIfProducerIsActive returns false, we did all we need to do
-    // inside that function, no need to call onNack
     bool old_nack = false;
 
-    if (schedule_next_interest){
-      if (interestRetransmissions_.find(segmentNumber) ==
+    if (interestRetransmissions_.find(segmentNumber) ==
             interestRetransmissions_.end()){
-        //this is not a retransmitted packet
-        old_nack = onNack(*content_object, false);
-        updateDelayStats(*content_object);
-      } else {
-        old_nack = onNack(*content_object, true);
-      }
+      //this is not a retransmitted packet
+      old_nack = onNack(*content_object, false);
+      updateDelayStats(*content_object);
+    } else {
+      old_nack = onNack(*content_object, true);
     }
 
     //the nacked_ state is used only to avoid to decrease inflightInterestsCount_
@@ -870,9 +834,7 @@ void RTCTransportProtocol::onContentObject(
 
   interestRetransmissions_.erase(segmentNumber);
 
-  if (schedule_next_interest) {
-    scheduleNextInterests();
-  }
+  scheduleNextInterests();
 }
 
 void RTCTransportProtocol::returnContentToApplication(
diff --git a/libtransport/src/hicn/transport/protocols/rtc.h b/libtransport/src/hicn/transport/protocols/rtc.h
index 4ebae2b90..509f11361 100644
--- a/libtransport/src/hicn/transport/protocols/rtc.h
+++ b/libtransport/src/hicn/transport/protocols/rtc.h
@@ -128,10 +128,6 @@ class RTCTransportProtocol : public TransportProtocol, public Reassembly {
   void checkRtx();
   void probeRtt();
   void onTimeout(Interest::Ptr &&interest) override;
-  // checkIfProducerIsActive: return true if we need to schedule an interest
-  // immediatly after, false otherwise (this happens when the producer socket
-  // is not active)
-  bool checkIfProducerIsActive(const ContentObject &content_object);
   bool onNack(const ContentObject &content_object, bool rtx);
   void onContentObject(Interest::Ptr &&interest,
                        ContentObject::Ptr &&content_object) override;
@@ -155,6 +151,7 @@ class RTCTransportProtocol : public TransportProtocol, public Reassembly {
   uint32_t inflightInterestsCount_;
   //map seq to rtx
   std::map<uint32_t, uint8_t> interestRetransmissions_;
+  bool rtx_timer_used_;
   std::unique_ptr<asio::steady_timer> rtx_timer_;
   std::vector<sentInterest> inflightInterests_;
   uint32_t lastSegNacked_; //indicates the segment id in the last received
@@ -163,12 +160,6 @@ class RTCTransportProtocol : public TransportProtocol, public Reassembly {
   uint32_t lastReceived_; //segment of the last content object received
                           //indicates the base of the window on the client
 
-  bool nack_timer_used_;
-  bool rtx_timer_used_;
-  std::unique_ptr<asio::steady_timer> nack_timer_;  // timer used to schedule
-  // a nack retransmission in case
-  // of inactive prod socket
-
   //rtt probes
   //the RTC transport tends to overestimate the RTT
   //du to the production time on the server side