chunks: react to congestion marks
Change-Id: I96efe1bc3ec7a54080c76676892114f2c79003ed
refs: #4289
diff --git a/tools/chunks/catchunks/pipeline-interests-aimd.cpp b/tools/chunks/catchunks/pipeline-interests-aimd.cpp
index b979a51..61ed8f3 100644
--- a/tools/chunks/catchunks/pipeline-interests-aimd.cpp
+++ b/tools/chunks/catchunks/pipeline-interests-aimd.cpp
@@ -33,6 +33,8 @@
namespace chunks {
namespace aimd {
+constexpr double PipelineInterestsAimd::MIN_SSTHRESH;
+
PipelineInterestsAimd::PipelineInterestsAimd(Face& face, RttEstimator& rttEstimator,
const Options& options)
: PipelineInterests(face)
@@ -46,6 +48,7 @@
, m_nInFlight(0)
, m_nLossEvents(0)
, m_nRetransmitted(0)
+ , m_nCongMarks(0)
, m_cwnd(m_options.initCwnd)
, m_ssthresh(m_options.initSsthresh)
, m_hasFailure(false)
@@ -244,7 +247,30 @@
m_nInFlight--;
}
- increaseWindow();
+ // upon finding congestion mark, decrease the window size
+ // without retransmitting any packet
+ if (data.getCongestionMark() > 0) {
+ m_nCongMarks++;
+ if (!m_options.ignoreCongMarks) {
+ if (m_options.disableCwa || m_highData > m_recPoint) {
+ m_recPoint = m_highInterest; // react to only one congestion event (timeout or congestion mark)
+ // per RTT (conservative window adaptation)
+ decreaseWindow();
+
+ if (m_options.isVerbose) {
+ std::cerr << "Received congestion mark, value = " << data.getCongestionMark()
+ << ", new cwnd = " << m_cwnd << std::endl;
+ }
+ }
+ }
+ else {
+ increaseWindow();
+ }
+ }
+ else {
+ increaseWindow();
+ }
+
onData(data);
if (segInfo.state == SegmentState::FirstTimeSent ||
@@ -324,7 +350,7 @@
m_nLossEvents++;
if (m_options.isVerbose) {
- std::cerr << "Packet loss event, cwnd = " << m_cwnd
+ std::cerr << "Packet loss event, new cwnd = " << m_cwnd
<< ", ssthresh = " << m_ssthresh << std::endl;
}
}
@@ -382,7 +408,7 @@
PipelineInterestsAimd::decreaseWindow()
{
// please refer to RFC 5681, Section 3.1 for the rationale behind it
- m_ssthresh = std::max(2.0, m_cwnd * m_options.mdCoef); // multiplicative decrease
+ m_ssthresh = std::max(MIN_SSTHRESH, m_cwnd * m_options.mdCoef); // multiplicative decrease
m_cwnd = m_options.resetCwndToInit ? m_options.initCwnd : m_ssthresh;
afterCwndChange(time::steady_clock::now() - getStartTime(), m_cwnd);
@@ -411,7 +437,8 @@
std::cerr << "Total # of packet loss events: " << m_nLossEvents << "\n"
<< "Packet loss rate: "
<< static_cast<double>(m_nLossEvents) / static_cast<double>(m_nReceived) << "\n"
- << "Total # of retransmitted segments: " << m_nRetransmitted << "\n";
+ << "Total # of retransmitted segments: " << m_nRetransmitted << "\n"
+ << "Total # of received congestion marks: " << m_nCongMarks << "\n";
}
std::ostream&
@@ -444,6 +471,7 @@
<< "\tMultiplicative decrease factor = " << options.mdCoef << "\n"
<< "\tRTO check interval = " << options.rtoCheckInterval << "\n"
<< "\tMax retries on timeout or Nack = " << options.maxRetriesOnTimeoutOrNack << "\n"
+ << "\tReaction to congestion marks " << (options.ignoreCongMarks ? "disabled" : "enabled") << "\n"
<< "\tConservative Window Adaptation " << (options.disableCwa ? "disabled" : "enabled") << "\n"
<< "\tResetting cwnd to " << (options.resetCwndToInit ? "initCwnd" : "ssthresh") << " upon loss event\n";
return os;