Disable packet probes

libraries/networking/src/udt/CongestionControl.h

@@ -46,6 +46,7 @@ public:
 
     virtual bool shouldNAK() { return true; }
     virtual bool shouldACK2() { return true; }
+    virtual bool shouldProbe() { return true; }
 
     virtual void onPacketSent(int packetSize, SequenceNumber seqNum, p_high_resolution_clock::time_point timePoint) {}
 protected:

libraries/networking/src/udt/Connection.cpp

@@ -125,6 +125,7 @@ SendQueue& Connection::getSendQueue() {
         _sendQueue->setSyncInterval(_synInterval);
         _sendQueue->setEstimatedTimeout(estimatedTimeout());
         _sendQueue->setFlowWindowSize(std::min(_flowWindowSize, (int) _congestionControl->_congestionWindowSize));
+        _sendQueue->setProbePacketEnabled(_congestionControl->shouldProbe());
 
         // give the randomized sequence number to the congestion control object
         _congestionControl->setInitialSendSequenceNumber(_sendQueue->getCurrentSequenceNumber());

libraries/networking/src/udt/SendQueue.cpp

@@ -396,6 +396,10 @@ void SendQueue::run() {
     }
 }
 
+void SendQueue::setProbePacketEnabled(bool enabled) {
+    _shouldSendProbes = enabled;
+}
+
 int SendQueue::maybeSendNewPacket() {
     if (!isFlowWindowFull()) {
         // we didn't re-send a packet, so time to send a new one
@@ -413,7 +417,7 @@ int SendQueue::maybeSendNewPacket() {
                 std::unique_ptr<Packet> secondPacket;
                 bool shouldSendPairTail = false;
 
-                if (((uint32_t) nextNumber & 0xF) == 0) {
+                if (_shouldSendProbes && ((uint32_t) nextNumber & 0xF) == 0) {
                     // the first packet is the first in a probe pair - every 16 (rightmost 16 bits = 0) packets
                     // pull off a second packet if we can before we unlock
                     shouldSendPairTail = true;

libraries/networking/src/udt/SendQueue.h

@@ -65,6 +65,8 @@ public:
     void setEstimatedTimeout(int estimatedTimeout) { _estimatedTimeout = estimatedTimeout; }
     void setSyncInterval(int syncInterval) { _syncInterval = syncInterval; }
 
+    void setProbePacketEnabled(bool enabled);
+    
 public slots:
     void stop();
     
@@ -140,6 +142,9 @@ private:
     std::condition_variable _handshakeACKCondition;
     
     std::condition_variable_any _emptyCondition;
+
+
+    std::atomic<bool> _shouldSendProbes { true };
 };
     
 }

libraries/networking/src/udt/TCPVegasCC.cpp

@@ -52,8 +52,6 @@ bool TCPVegasCC::onACK(SequenceNumber ack, p_high_resolution_clock::time_point r
                             + abs(lastRTT - _ewmaRTT)) / RTT_ESTIMATION_VARIANCE_ALPHA_NUMERATOR;
         }
 
-
-
         // keep track of the lowest RTT during connection
         _baseRTT = std::min(_baseRTT, lastRTT);
 

libraries/networking/src/udt/TCPVegasCC.h

@@ -33,6 +33,7 @@ public:
 
     virtual bool shouldNAK() override { return false; }
     virtual bool shouldACK2() override { return false; }
+    virtual bool shouldProbe() override { return false; }
 
     virtual void onPacketSent(int packetSize, SequenceNumber seqNum, p_high_resolution_clock::time_point timePoint) override;