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1. Use EWMA for stream RTT estimation;

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2. Drop window size by 10% instead of 50% in case of resend.

Change is based on code by onon.
This commit is contained in:
Vort 2024-03-06 14:54:02 +02:00
parent bb702700f7
commit 3ceb64db2e
2 changed files with 8 additions and 3 deletions
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9
libi2pd/Streaming.cpp
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@ -433,7 +433,10 @@ namespace stream
LogPrint(eLogError, "Streaming: Packet ", seqn, "sent from the future, sendTime=", sentPacket->sendTime);
rtt = 1;
}
m_RTT = std::round ((m_RTT*seqn + rtt)/(seqn + 1.0));
if (seqn)
m_RTT = std::round (RTT_EWMA_ALPHA * m_RTT + (1.0 - RTT_EWMA_ALPHA) * rtt);
else
m_RTT = rtt;
m_RTO = m_RTT*1.5; // TODO: implement it better
LogPrint (eLogDebug, "Streaming: Packet ", seqn, " acknowledged rtt=", rtt, " sentTime=", sentPacket->sendTime);
m_SentPackets.erase (it++);
@ -998,8 +1001,8 @@ namespace stream
m_RTO *= 2;
switch (m_NumResendAttempts)
{
case 1: // congesion avoidance
m_WindowSize >>= 1; // /2
case 1: // congestion avoidance
m_WindowSize -= (m_WindowSize + WINDOW_SIZE_DROP_FRACTION) / WINDOW_SIZE_DROP_FRACTION; // adjustment >= 1
if (m_WindowSize < MIN_WINDOW_SIZE) m_WindowSize = MIN_WINDOW_SIZE;
break;
case 2:

2
libi2pd/Streaming.h
View File

@ -56,6 +56,8 @@ namespace stream
const int WINDOW_SIZE = 6; // in messages
const int MIN_WINDOW_SIZE = 1;
const int MAX_WINDOW_SIZE = 128;
const int WINDOW_SIZE_DROP_FRACTION = 10; // 1/10
const double RTT_EWMA_ALPHA = 0.5;
const int INITIAL_RTT = 8000; // in milliseconds
const int INITIAL_RTO = 9000; // in milliseconds
const int MIN_SEND_ACK_TIMEOUT = 2; // in milliseconds