65 lines
1.4 KiB
C++
65 lines
1.4 KiB
C++
#include "./cubic.hpp"
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#include <cmath>
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#include <iostream>
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float CUBIC::getCWnD(void) const {
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const double K = cbrt(
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(_window_max * (1. - BETA)) / SCALING_CONSTANT
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);
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const double time_since_reduction = getTimeNow() - _time_point_reduction;
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const double TK = time_since_reduction - K;
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const double cwnd =
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SCALING_CONSTANT
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* TK * TK * TK // TK^3
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+ _window_max
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;
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#if 0
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std::cout
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<< "K:" << K
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<< " ts:" << time_since_reduction
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<< " TK:" << TK
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<< " cwnd:" << cwnd
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<< " rtt:" << getCurrentDelay()
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<< "\n"
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;
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#endif
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return std::max<float>(cwnd, 2.f * MAXIMUM_SEGMENT_SIZE);
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}
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void CUBIC::onCongestion(void) {
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if (getTimeNow() - _time_point_reduction >= getCurrentDelay()*4.f) {
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const auto current_cwnd = getCWnD();
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_time_point_reduction = getTimeNow();
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_window_max = current_cwnd * BETA;
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_window_max = std::max(_window_max, 2.*MAXIMUM_SEGMENT_SIZE);
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//std::cout << "CONGESTION! cwnd:" << current_cwnd << "\n";
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std::cout << "CONGESTION! cwnd_max:" << _window_max << "\n";
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}
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}
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size_t CUBIC::canSend(void) {
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const auto fspace_pkgs = FlowOnly::canSend();
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if (fspace_pkgs == 0u) {
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return 0u;
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}
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const int64_t cspace_bytes = getCWnD() - _in_flight_bytes;
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if (cspace_bytes < MAXIMUM_SEGMENT_DATA_SIZE) {
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return 0u;
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}
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// limit to whole packets
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size_t cspace_pkgs = std::floor(cspace_bytes / MAXIMUM_SEGMENT_DATA_SIZE) * MAXIMUM_SEGMENT_DATA_SIZE;
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return std::min(cspace_pkgs, fspace_pkgs);
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}
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