From 1c5f4f24a799d78da0a29f83c789a80256fe677a Mon Sep 17 00:00:00 2001
From: Green Sky <green@g-s.xyz>
Date: Thu, 24 Aug 2023 01:28:13 +0200
Subject: [PATCH] only allow 1 congestion event per rtt

---
 solanaceae/ngc_ft1/cca.hpp    |  2 +-
 solanaceae/ngc_ft1/ledbat.cpp | 14 +++++++++-----
 solanaceae/ngc_ft1/ledbat.hpp |  7 +++++--
 3 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/solanaceae/ngc_ft1/cca.hpp b/solanaceae/ngc_ft1/cca.hpp
index aa017bf..37d8509 100644
--- a/solanaceae/ngc_ft1/cca.hpp
+++ b/solanaceae/ngc_ft1/cca.hpp
@@ -33,7 +33,7 @@ struct CCAI {
 		CCAI(size_t maximum_segment_data_size) : MAXIMUM_SEGMENT_DATA_SIZE(maximum_segment_data_size) {}
 
 		// return the current believed window in bytes of how much data can be inflight,
-		virtual float getCWnD(void) const = 0;
+		//virtual float getCWnD(void) const = 0;
 
 		// TODO: api for how much data we should send
 		// take time since last sent into account
diff --git a/solanaceae/ngc_ft1/ledbat.cpp b/solanaceae/ngc_ft1/ledbat.cpp
index 49e8580..c20a511 100644
--- a/solanaceae/ngc_ft1/ledbat.cpp
+++ b/solanaceae/ngc_ft1/ledbat.cpp
@@ -112,10 +112,6 @@ void LEDBAT::onLoss(SeqIDType seq, bool discard) {
 		return; // not found, ignore ??
 	}
 
-	_recently_lost_data = true;
-
-	// at most once per rtt?
-
 	if (PLOTTING) {
 		std::cerr << "CCA: onLoss: TIME: " << getTimeNow() << "\n";
 	}
@@ -128,7 +124,15 @@ void LEDBAT::onLoss(SeqIDType seq, bool discard) {
 	}
 	// TODO: reset timestamp?
 
-	updateWindows();
+	// at most once per rtt?
+	// TODO: use delay at event instead
+	if (getTimeNow() >= _last_congestion_event + _last_congestion_rtt) {
+		_recently_lost_data = true;
+		_last_congestion_event = getTimeNow();
+		_last_congestion_rtt = getCurrentDelay();
+
+		updateWindows();
+	}
 }
 
 float LEDBAT::getCurrentDelay(void) const {
diff --git a/solanaceae/ngc_ft1/ledbat.hpp b/solanaceae/ngc_ft1/ledbat.hpp
index 6113550..b023f92 100644
--- a/solanaceae/ngc_ft1/ledbat.hpp
+++ b/solanaceae/ngc_ft1/ledbat.hpp
@@ -54,7 +54,7 @@ struct LEDBAT : public CCAI{
 
 		// return the current believed window in bytes of how much data can be inflight,
 		// without overstepping the delay requirement
-		float getCWnD(void) const override {
+		float getCWnD(void) const {
 			return _cwnd;
 		}
 
@@ -100,9 +100,12 @@ struct LEDBAT : public CCAI{
 
 		float _last_cwnd {0.f}; // timepoint of last cwnd correction
 		int64_t _recently_acked_data {0}; // reset on _last_cwnd
-		bool _recently_lost_data {false};
 		int64_t _recently_sent_bytes {0};
 
+		bool _recently_lost_data {false};
+		float _last_congestion_event {0.f};
+		float _last_congestion_rtt {0.5f};
+
 		// initialize to low value, will get corrected very fast
 		float _fwnd {0.01f * max_byterate_allowed}; // in bytes