[FR] Added response time statistics

srtcore/common.h

@@ -1473,6 +1473,11 @@ struct MetricOp
     {
         m = 0;
     }
+
+    static bool is_zero(const METRIC_TYPE& m)
+    {
+        return m == 0;
+    }
 };
 
 template <>
@@ -1485,4 +1490,19 @@ struct MetricOp<PacketMetric>
     }
 };
 
+template <>
+struct MetricOp<srt::sync::steady_clock::duration>
+{
+    typedef srt::sync::steady_clock::duration duration;
+    static bool is_zero(const duration& m)
+    {
+        return m == duration::zero();
+    }
+
+    static void Clear(duration& m)
+    {
+        m = duration::zero();
+    }
+};
+
 #endif

srtcore/core.cpp

@@ -1486,6 +1486,8 @@ void CUDT::clearData()
         m_stats.traceRcvBytesUndecrypt   = 0;
 
         m_stats.sndDuration = m_stats.m_sndDurationTotal = 0;
+        m_stats.tdAverageResponseTime.Init();
+        m_stats.tdMaxResponseTime.Init();
     }
 
     // Resetting these data because this happens when agent isn't connected.
@@ -7448,6 +7450,11 @@ void CUDT::bstats(CBytePerfMon *perf, bool clear, bool instantaneous)
         perf->msRcvBuf   = 0;
     }
 
+    perf->msAvgResponseTimeTotal = count_milliseconds(m_stats.tdAverageResponseTime.total);
+    perf->msMaxResponseTimeTotal = count_milliseconds(m_stats.tdMaxResponseTime.total);
+    perf->msAvgResponseTime = count_milliseconds(m_stats.tdAverageResponseTime.local);
+    perf->msMaxResponseTime = count_milliseconds(m_stats.tdMaxResponseTime.local);
+
     if (clear)
     {
         m_stats.traceSndDrop           = 0;
@@ -7474,6 +7481,8 @@ void CUDT::bstats(CBytePerfMon *perf, bool clear, bool instantaneous)
         m_stats.rcvFilterLoss   = 0;
 
         m_stats.tsLastSampleTime = currtime;
+        m_stats.tdAverageResponseTime.Clear();
+        m_stats.tdMaxResponseTime.Clear();
     }
 }
 
@@ -8439,7 +8448,7 @@ void CUDT::processCtrl(const CPacket &ctrlpkt)
     // Just heard from the peer, reset the expiration count.
     m_iEXPCount = 1;
     const steady_clock::time_point currtime = steady_clock::now();
-    m_tsLastRspTime = currtime;
+    calculateResponseTime(currtime);
     bool using_rexmit_flag = m_bPeerRexmitFlag;
 
     HLOGC(inlog.Debug,
@@ -9347,7 +9356,7 @@ int CUDT::processData(CUnit* in_unit)
     // m_pRcvBuffer->addLocalTsbPdDriftSample(packet.getMsgTimeStamp());
     // Just heard from the peer, reset the expiration count.
     m_iEXPCount = 1;
-    m_tsLastRspTime = steady_clock::now();
+    calculateResponseTime(steady_clock::now());
 
     const bool need_tsbpd = m_bTsbPd || m_bGroupTsbPd;
 

srtcore/core.h

@@ -138,6 +138,51 @@ enum SeqPairItems
     SEQ_BEGIN = 0, SEQ_END = 1, SEQ_SIZE = 2
 };
 
+template <class METRIC_TYPE>
+struct AverageMetricUsage: public MetricUsage<METRIC_TYPE>
+{
+    using MetricUsage<METRIC_TYPE>::Clear;
+    using MetricUsage<METRIC_TYPE>::Init;
+    using MetricUsage<METRIC_TYPE>::local;
+    using MetricUsage<METRIC_TYPE>::total;
+
+    void Update(METRIC_TYPE value)
+    {
+        if (MetricOp<METRIC_TYPE>::is_zero(local))
+            local = value;
+        else
+        {
+            local = (local + value)/2;
+        }
+
+        if (MetricOp<METRIC_TYPE>::is_zero(total))
+            total = value;
+        else
+        {
+            total = (total + value)/2;
+        }
+    }
+};
+
+
+template <class METRIC_TYPE>
+struct MaxMetricUsage: public MetricUsage<METRIC_TYPE>
+{
+    using MetricUsage<METRIC_TYPE>::Clear;
+    using MetricUsage<METRIC_TYPE>::Init;
+    using MetricUsage<METRIC_TYPE>::local;
+    using MetricUsage<METRIC_TYPE>::total;
+
+    void Update(METRIC_TYPE value)
+    {
+        if (value > local)
+            local = value;
+
+        if (value > total)
+            total = value;
+    }
+};
+
 #if ENABLE_EXPERIMENTAL_BONDING
 
 struct SRT_SocketOptionObject
@@ -1139,8 +1184,30 @@ class CUDT
 
         int64_t sndDuration;                // real time for sending
         time_point sndDurationCounter;         // timers to record the sending Duration
+
+        AverageMetricUsage<duration> tdAverageResponseTime;
+        MaxMetricUsage<duration> tdMaxResponseTime;
     } m_stats;
 
+    /// This function records the passed current time as the last response time.
+    /// Before doing it, however, it checks if there exist any previous such time
+    /// and updates statistics accordingly.
+    void calculateResponseTime(const time_point& now)
+    {
+        using namespace srt::sync;
+
+        if (!is_zero(m_tsLastRspTime))
+        {
+            duration td = now - m_tsLastRspTime;
+            enterCS(m_StatsLock);
+            m_stats.tdAverageResponseTime.Update(td);
+            m_stats.tdMaxResponseTime.Update(td);
+            leaveCS(m_StatsLock);
+        }
+
+        m_tsLastRspTime = now;
+    }
+
 public:
     static const int SELF_CLOCK_INTERVAL = 64;  // ACK interval for self-clocking
     static const int SEND_LITE_ACK = sizeof(int32_t); // special size for ack containing only ack seq

srtcore/srt.h

@@ -403,12 +403,16 @@ struct CBytePerfMon
    int64_t  pktRecvUniqueTotal;         // total number of packets to be received by the application
    uint64_t byteSentUniqueTotal;        // total number of data bytes, sent by the application
    uint64_t byteRecvUniqueTotal;        // total number of data bytes to be received by the application
+   uint32_t msAvgResponseTimeTotal;
+   uint32_t msMaxResponseTimeTotal;
 
    // Local
    int64_t  pktSentUnique;              // number of data packets sent by the application
    int64_t  pktRecvUnique;              // number of packets to be received by the application
    uint64_t byteSentUnique;             // number of data bytes, sent by the application
    uint64_t byteRecvUnique;             // number of data bytes to be received by the application
+   uint32_t msAvgResponseTime;
+   uint32_t msMaxResponseTime;
 };
 
 ////////////////////////////////////////////////////////////////////////////////