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[core] FileCC improvements
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@maxsharabayko @rndi
maxsharabayko authored and rndi committed Sep 3, 2019
1 parent 080b158 commit bc52749
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Showing 3 changed files with 56 additions and 25 deletions.
77 changes: 53 additions & 24 deletions srtcore/congctl.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -244,11 +244,11 @@ class LiveCC: public SrtCongestionControlBase
};


class FileCC: public SrtCongestionControlBase
class FileCC : public SrtCongestionControlBase
{
typedef FileCC Me; // Required by SSLOT macro

// Fields from CCC not used by LiveCC
// Fields from CCC not used by FileCC
int m_iACKPeriod;

// Fields from CUDTCC
Expand Down Expand Up @@ -301,7 +301,7 @@ class FileCC: public SrtCongestionControlBase
HLOGC(mglog.Debug, log << "Creating FileCC");
}

bool checkTransArgs(SrtCongestion::TransAPI, SrtCongestion::TransDir, const char* , size_t , int , bool ) ATR_OVERRIDE
bool checkTransArgs(SrtCongestion::TransAPI, SrtCongestion::TransDir, const char*, size_t, int, bool) ATR_OVERRIDE
{
// XXX
// The FileCC has currently no restrictions, although it should be
Expand Down Expand Up @@ -355,8 +355,8 @@ class FileCC: public SrtCongestionControlBase
m_dPktSndPeriod = 1000000.0 / m_parent->deliveryRate();
HLOGC(mglog.Debug, log << "FileCC: UPD (slowstart:ENDED) wndsize="
<< m_dCWndSize << "/" << m_dMaxCWndSize
<< " sndperiod=" << m_dPktSndPeriod << "us = mega/("
<< m_parent->deliveryRate() << "pkts/s)");
<< " sndperiod=" << m_dPktSndPeriod << "us = 1M/("
<< m_parent->deliveryRate() << " pkts/s)");
}
else
{
Expand All @@ -377,34 +377,44 @@ class FileCC: public SrtCongestionControlBase
else
{
m_dCWndSize = m_parent->deliveryRate() / 1000000.0 * (m_parent->RTT() + m_iRCInterval) + 16;
HLOGC(mglog.Debug, log << "FileCC: UPD (speed mode) wndsize="
<< m_dCWndSize << "/" << m_dMaxCWndSize << " RTT = " << m_parent->RTT()
<< " sndperiod=" << m_dPktSndPeriod << "us. deliverRate = "
<< m_parent->deliveryRate() << " pkts/s)");
}

// No rate increase during Slow Start
if (!m_bSlowStart)
{
if (m_bLoss)
{
m_bLoss = false;
}
// During Slow Start, no rate increase
else
{
double inc = 0;
int64_t B = (int64_t)(m_parent->bandwidth() - 1000000.0 / m_dPktSndPeriod);
if ((m_dPktSndPeriod > m_dLastDecPeriod) && ((m_parent->bandwidth() / 9) < B))
B = m_parent->bandwidth() / 9;
const int loss_bw = 2 * (1000000 / m_dLastDecPeriod); // 2 times last loss point
const int bw_pktps = min(loss_bw, m_parent->bandwidth());

int64_t B = (int64_t)(bw_pktps - 1000000.0 / m_dPktSndPeriod);
if ((m_dPktSndPeriod > m_dLastDecPeriod) && ((bw_pktps / 9) < B))
B = bw_pktps / 9;
if (B <= 0)
inc = 1.0 / m_parent->MSS(); // was inc = 0.01; in UDT
inc = 1.0 / m_parent->MSS();
else
{
// inc = max(10 ^ ceil(log10( B * MSS * 8 ) * Beta / MSS, 1/MSS)
// Beta = 1.5 * 10^(-6)

inc = pow(10.0, ceil(log10(B * m_parent->MSS() * 8.0))) * 0.0000015 / m_parent->MSS();

if (inc < 1.0 / m_parent->MSS())
inc = 1.0 / m_parent->MSS();
inc = max(inc, 1.0 / m_parent->MSS());
}

HLOGC(mglog.Debug, log << "FileCC: UPD (slowstart:OFF) loss_bw=" << loss_bw
<< " bandwidth=" << m_parent->bandwidth() << " inc=" << inc
<< " m_dPktSndPeriod=" << m_dPktSndPeriod
<< "->" << (m_dPktSndPeriod * m_iRCInterval) / (m_dPktSndPeriod * inc + m_iRCInterval));

m_dPktSndPeriod = (m_dPktSndPeriod * m_iRCInterval) / (m_dPktSndPeriod * inc + m_iRCInterval);
}
}
Expand Down Expand Up @@ -455,7 +465,7 @@ class FileCC: public SrtCongestionControlBase

// Sanity check. Should be impossible that TEV_LOSSREPORT event
// is called with a nonempty loss list.
if ( losslist_size == 0 )
if (losslist_size == 0)
{
LOGC(mglog.Error, log << "IPE: FileCC: empty loss list!");
return;
Expand All @@ -482,6 +492,23 @@ class FileCC: public SrtCongestionControlBase

m_bLoss = true;

const int pktsInFlight = m_parent->RTT() / m_dPktSndPeriod;
const int ackSeqno = m_iLastAck;// m_parent->sndLastDataAck();
const int sentSeqno = m_parent->sndSeqNo();
const int numPktsLost = m_parent->sndLossLength();
const int lost_pcent_x10 = (numPktsLost * 1000) / pktsInFlight;

HLOGC(mglog.Debug, log << "FileSmootherV2: LOSS: "
<< "sent=" << CSeqNo::seqlen(ackSeqno, sentSeqno) << ", inFlight=" << pktsInFlight
<< ", lost=" << numPktsLost << " ("
<< lost_pcent_x10 / 10 << "." << lost_pcent_x10 % 10 << "\%)");
if (lost_pcent_x10 < 20) // 2.0%
{
HLOGC(mglog.Debug, log << "FileSmootherV2: LOSS: m_dLastDecPeriod=" << m_dLastDecPeriod << "->" << m_dPktSndPeriod);
m_dLastDecPeriod = m_dPktSndPeriod;
return;
}

// In contradiction to UDT, TEV_LOSSREPORT will be reported also when
// the lossreport is being sent again, periodically, as a result of
// NAKREPORT feature. You should make sure that NAKREPORT is off when
Expand All @@ -492,9 +519,10 @@ class FileCC: public SrtCongestionControlBase
if (CSeqNo::seqcmp(lossbegin, m_iLastDecSeq) > 0)
{
m_dLastDecPeriod = m_dPktSndPeriod;
m_dPktSndPeriod = ceil(m_dPktSndPeriod * 1.125);
m_dPktSndPeriod = ceil(m_dPktSndPeriod * 1.03);

m_iAvgNAKNum = (int)ceil(m_iAvgNAKNum * 0.875 + m_iNAKCount * 0.125);
const double loss_share_factor = 0.03;
m_iAvgNAKNum = (int)ceil(m_iAvgNAKNum * (1 - loss_share_factor) + m_iNAKCount * loss_share_factor);
m_iNAKCount = 1;
m_iDecCount = 1;

Expand All @@ -505,33 +533,34 @@ class FileCC: public SrtCongestionControlBase
m_iDecRandom = (int)ceil(m_iAvgNAKNum * (double(rand()) / RAND_MAX));
if (m_iDecRandom < 1)
m_iDecRandom = 1;
HLOGC(mglog.Debug, log << "FileCC: LOSS:NEW lastseq=" << m_iLastDecSeq
HLOGC(mglog.Debug, log << "FileCC: LOSS:NEW lseqno=" << lossbegin
<< ", lastsentseqno=" << m_iLastDecSeq
<< ", seqdiff=" << CSeqNo::seqoff(m_iLastDecSeq, lossbegin)
<< ", rand=" << m_iDecRandom
<< " avg NAK:" << m_iAvgNAKNum
<< ", sndperiod=" << m_dPktSndPeriod << "us");
}
else if ((m_iDecCount ++ < 5) && (0 == (++ m_iNAKCount % m_iDecRandom)))
else if ((m_iDecCount++ < 5) && (0 == (++m_iNAKCount % m_iDecRandom)))
{
// 0.875^5 = 0.51, rate should not be decreased by more than half within a congestion period
m_dPktSndPeriod = ceil(m_dPktSndPeriod * 1.125);
m_dPktSndPeriod = ceil(m_dPktSndPeriod * 1.03);
m_iLastDecSeq = m_parent->sndSeqNo();
HLOGC(mglog.Debug, log << "FileCC: LOSS:PERIOD lseq=" << lossbegin
<< ", dseq=" << m_iLastDecSeq
HLOGC(mglog.Debug, log << "FileCC: LOSS:PERIOD lseqno=" << lossbegin
<< ", lastsentseqno=" << m_iLastDecSeq
<< ", seqdiff=" << CSeqNo::seqoff(m_iLastDecSeq, lossbegin)
<< ", deccnt=" << m_iDecCount
<< ", decrnd=" << m_iDecRandom
<< ", sndperiod=" << m_dPktSndPeriod << "us");
}
else
{
HLOGC(mglog.Debug, log << "FileCC: LOSS:STILL lseq=" << lossbegin
<< ", dseq=" << m_iLastDecSeq
HLOGC(mglog.Debug, log << "FileCC: LOSS:STILL lseqno=" << lossbegin
<< ", lastsentseqno=" << m_iLastDecSeq
<< ", seqdiff=" << CSeqNo::seqoff(m_iLastDecSeq, lossbegin)
<< ", deccnt=" << m_iDecCount
<< ", decrnd=" << m_iDecRandom
<< ", sndperiod=" << m_dPktSndPeriod << "us");
}

}

void speedupToWindowSize(ETransmissionEvent, EventVariant arg)
Expand Down
3 changes: 2 additions & 1 deletion srtcore/core.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -7105,7 +7105,6 @@ void CUDT::processCtrl(CPacket& ctrlpkt)
{
int32_t* losslist = (int32_t *)(ctrlpkt.m_pcData);
size_t losslist_len = ctrlpkt.getLength() / 4;
updateCC(TEV_LOSSREPORT, EventVariant(losslist, losslist_len));

bool secure = true;

Expand Down Expand Up @@ -7178,6 +7177,8 @@ void CUDT::processCtrl(CPacket& ctrlpkt)
}
CGuard::leaveCS(m_AckLock);

updateCC(TEV_LOSSREPORT, EventVariant(losslist, losslist_len));

if (!secure)
{
HLOGF(mglog.Debug, "WARNING: out-of-band LOSSREPORT received; considered bug or attack");
Expand Down
1 change: 1 addition & 0 deletions srtcore/core.h
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Original file line number Diff line number Diff line change
Expand Up @@ -269,6 +269,7 @@ class CUDT
size_t OPT_PayloadSize() { return m_zOPT_ExpPayloadSize; }
uint64_t minNAKInterval() { return m_ullMinNakInt_tk; }
int32_t ISN() { return m_iISN; }
int sndLossLength() { return m_pSndLossList->getLossLength(); }

// XXX See CUDT::tsbpd() to see how to implement it. This should
// do the same as TLPKTDROP feature when skipping packets that are agreed
Expand Down

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