From a97be6937a7b14fb355cf97f67c703f0d64f6b70 Mon Sep 17 00:00:00 2001
From: Arvid Norberg <arvid@libtorrent.org>
Date: Mon, 10 Mar 2008 03:30:01 +0000
Subject: [PATCH] unchoker counts bytes instead of rates

---
 include/libtorrent/peer_connection.hpp | 17 ++++++++++++++++
 src/peer_connection.cpp                | 27 ++++++++++++++++++++++++++
 src/session_impl.cpp                   | 10 ++++------
 3 files changed, 48 insertions(+), 6 deletions(-)

diff --git a/include/libtorrent/peer_connection.hpp b/include/libtorrent/peer_connection.hpp
index b6ef25e20..1ed0712c7 100755
--- a/include/libtorrent/peer_connection.hpp
+++ b/include/libtorrent/peer_connection.hpp
@@ -286,6 +286,15 @@ namespace libtorrent
 
 		int desired_queue_size() const { return m_desired_queue_size; }
 
+		// compares this connection against the given connection
+		// for which one is more eligible for an unchoke.
+		// returns true if this is more eligible
+		bool unchoke_compare(boost::intrusive_ptr<peer_connection const> const& p) const;
+
+		// resets the byte counters that are used to measure
+		// the number of bytes transferred within unchoke cycles
+		void reset_choke_counters();
+
 #if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_ERROR_LOGGING
 		boost::shared_ptr<logger> m_logger;
 #endif
@@ -750,6 +759,14 @@ namespace libtorrent
 		// was called to when on_connection_complete
 		// was called. The rtt is specified in milliseconds
 		int m_rtt;
+
+		// the total payload download bytes
+		// at the last unchoke cycle. This is used to
+		// measure the number of bytes transferred during
+		// an unchoke cycle, to unchoke peers the more bytes
+		// they sent us
+		size_type m_downloaded_at_last_unchoke;
+
 #ifndef NDEBUG
 	public:
 		bool m_in_constructor;
diff --git a/src/peer_connection.cpp b/src/peer_connection.cpp
index 7aaa34bfe..981b912ca 100755
--- a/src/peer_connection.cpp
+++ b/src/peer_connection.cpp
@@ -119,6 +119,7 @@ namespace libtorrent
 		, m_outstanding_writing_bytes(0)
 		, m_fast_reconnect(false)
 		, m_rtt(0)
+		, m_downloaded_at_last_unchoke(0)
 #ifndef NDEBUG
 		, m_in_constructor(true)
 #endif
@@ -202,6 +203,7 @@ namespace libtorrent
 		, m_outstanding_writing_bytes(0)
 		, m_fast_reconnect(false)
 		, m_rtt(0)
+		, m_downloaded_at_last_unchoke(0)
 #ifndef NDEBUG
 		, m_in_constructor(true)
 #endif
@@ -239,6 +241,31 @@ namespace libtorrent
 		std::fill(m_peer_id.begin(), m_peer_id.end(), 0);
 	}
 
+	bool peer_connection::unchoke_compare(boost::intrusive_ptr<peer_connection const> const& p) const
+	{
+		TORRENT_ASSERT(p);
+		peer_connection const& rhs = *p;
+
+		// first compare how many bytes they've sent us
+		size_type c1 = m_statistics.total_payload_download() - m_downloaded_at_last_unchoke;
+		size_type c2 = rhs.m_statistics.total_payload_download() - rhs.m_downloaded_at_last_unchoke;
+		if (c1 > c2) return true;
+		if (c1 < c2) return false;
+
+		// if they are equal, compare how much we have uploaded
+		if (m_peer_info) c1 = m_peer_info->total_upload();
+		else c1 = m_statistics.total_payload_upload();
+		if (rhs.m_peer_info) c2 = rhs.m_peer_info->total_upload();
+		else c2 = rhs.m_statistics.total_payload_upload();
+
+		return c1 < c2;
+	}
+
+	void peer_connection::reset_choke_counters()
+	{
+		m_downloaded_at_last_unchoke = m_statistics.total_payload_download();
+	}
+
 	void peer_connection::update_interest()
 	{
 		INVARIANT_CHECK;
diff --git a/src/session_impl.cpp b/src/session_impl.cpp
index 89cc122e0..653ae4ab4 100755
--- a/src/session_impl.cpp
+++ b/src/session_impl.cpp
@@ -1016,17 +1016,15 @@ namespace aux {
 				peers.push_back(i->get());
 			}
 
-			// sort the peers that are eligible for unchoke by download rate and secondary
+			// sorts the peers that are eligible for unchoke by download rate and secondary
 			// by total upload. The reason for this is, if all torrents are being seeded,
 			// the download rate will be 0, and the peers we have sent the least to should
 			// be unchoked
 			std::sort(peers.begin(), peers.end()
-				, bind(&stat::total_payload_upload, bind(&peer_connection::statistics, _1))
-				< bind(&stat::total_payload_upload, bind(&peer_connection::statistics, _2)));
+				, bind(&peer_connection::unchoke_compare, _1, _2));
 
-			std::stable_sort(peers.begin(), peers.end()
-				, bind(&stat::download_payload_rate, bind(&peer_connection::statistics, _1))
-				> bind(&stat::download_payload_rate, bind(&peer_connection::statistics, _2)));
+			std::for_each(m_connections.begin(), m_connections.end()
+				, bind(&peer_connection::reset_choke_counters, _1));
 
 			// auto unchoke
 			int upload_limit = m_bandwidth_manager[peer_connection::upload_channel]->throttle();