[core] Stats: do not count discarded packets as dropped.

Valid for a broadcast group member dropping existing packets from the RCV buffer because they were read from another member.
Haivision · Apr 19, 2024 · d83c780 · d83c780
1 parent cf13200
commit d83c780
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Showing 3 changed files with 17 additions and 7 deletions.
diff --git a/srtcore/buffer_rcv.cpp b/srtcore/buffer_rcv.cpp
@@ -206,7 +206,7 @@ int CRcvBuffer::insert(CUnit* unit)
     return 0;
 }
 
-int CRcvBuffer::dropUpTo(int32_t seqno)
+std::pair<int, int> CRcvBuffer::dropUpTo(int32_t seqno)
 {
     IF_RCVBUF_DEBUG(ScopedLog scoped_log);
     IF_RCVBUF_DEBUG(scoped_log.ss << "CRcvBuffer::dropUpTo: seqno " << seqno << " m_iStartSeqNo " << m_iStartSeqNo);
@@ -222,9 +222,16 @@ int CRcvBuffer::dropUpTo(int32_t seqno)
     if (m_iMaxPosOff < 0)
         m_iMaxPosOff = 0;
 
-    const int iDropCnt = len;
+    int iNumDropped = 0; // Number of dropped packets that were missing.
+    int iNumDiscarded = 0; // The number of dropped packets that existed in the buffer.
     while (len > 0)
     {
+        // Note! Dropping a EntryState_Read must not be counted as a drop because it was read.
+        // Note! Dropping a EntryState_Drop must not be counted as a drop because it was already dropped and counted earlier.
+        if (m_entries[m_iStartPos].status == EntryState_Avail)
+			++iNumDiscarded;
+        else if (m_entries[m_iStartPos].status == EntryState_Empty)
+			++iNumDropped;
         dropUnitInPos(m_iStartPos);
         m_entries[m_iStartPos].status = EntryState_Empty;
         SRT_ASSERT(m_entries[m_iStartPos].pUnit == NULL && m_entries[m_iStartPos].status == EntryState_Empty);
@@ -246,7 +253,7 @@ int CRcvBuffer::dropUpTo(int32_t seqno)
     }
     if (!m_tsbpd.isEnabled() && m_bMessageAPI)
         updateFirstReadableOutOfOrder();
-    return iDropCnt;
+    return std::make_pair(iNumDropped, iNumDiscarded);
 }
 
 int CRcvBuffer::dropAll()

diff --git a/srtcore/buffer_rcv.h b/srtcore/buffer_rcv.h
@@ -66,8 +66,8 @@ class CRcvBuffer
 
     /// Drop packets in the receiver buffer from the current position up to the seqno (excluding seqno).
     /// @param [in] seqno drop units up to this sequence number
-    /// @return  number of dropped packets.
-    int dropUpTo(int32_t seqno);
+    /// @return number of dropped (missing) and discarded (available) packets as a pair(dropped, discarded).
+    std::pair<int, int> dropUpTo(int32_t seqno);
 
     /// @brief Drop all the packets in the receiver buffer.
     /// The starting position and seqno are shifted right after the last packet in the buffer.

diff --git a/srtcore/core.cpp b/srtcore/core.cpp
@@ -5584,7 +5584,10 @@ int srt::CUDT::rcvDropTooLateUpTo(int seqno)
 
     dropFromLossLists(SRT_SEQNO_NONE, CSeqNo::decseq(seqno));
 
-    const int iDropCnt = m_pRcvBuffer->dropUpTo(seqno);
+    const std::pair<int, int> iDropDiscardedPkts = m_pRcvBuffer->dropUpTo(seqno);
+    const int iDropCnt = iDropDiscardedPkts.first;
+    const int iDiscardedCnt = iDropDiscardedPkts.second;
+    const int iDropCntTotal = iDropCnt + iDiscardedCnt;
     if (iDropCnt > 0)
     {
         enterCS(m_StatsLock);
@@ -5593,7 +5596,7 @@ int srt::CUDT::rcvDropTooLateUpTo(int seqno)
         m_stats.rcvr.dropped.count(stats::BytesPackets(iDropCnt * avgpayloadsz, (uint32_t) iDropCnt));
         leaveCS(m_StatsLock);
     }
-    return iDropCnt;
+    return iDropCntTotal;
 }
 
 void srt::CUDT::setInitialRcvSeq(int32_t isn)