make torrent priority stricly prefer unchoking peers on high priority torrents

docs/manual.rst

@@ -2934,8 +2934,9 @@ consume, even if there's is more quota. Other peers will still be weighed in whe
 bandwidth is being distributed. With other words, bandwidth is not distributed strictly
 in order of priority, but the priority is used as a weight.
 
-Torrents with higher priority are also more likely to have its peers unchoked, to
+Peers whose Torrent has a higher priority will take precedence when distributing unchoke slots.
-distribute more upload capacity to them.
+This is a strict prioritization where every interested peer on a high priority torrent will
+be unchoked before any other, lower priority, torrents have any peers unchoked.
 
 use_interface()
 ---------------

src/peer_connection.cpp

@@ -422,24 +422,23 @@ namespace libtorrent
 		TORRENT_ASSERT(p);
 		peer_connection const& rhs = *p;
 
-		size_type c1;
+		// if one peer belongs to a higher priority torrent than the other one
-		size_type c2;
+		// that one should be unchoked.
-
-		// first compare how many bytes they've sent us
-		c1 = m_statistics.total_payload_download() - m_downloaded_at_last_unchoke;
-		c2 = rhs.m_statistics.total_payload_download() - rhs.m_downloaded_at_last_unchoke;
-
 		boost::shared_ptr<torrent> t1 = m_torrent.lock();
 		TORRENT_ASSERT(t1);
 		boost::shared_ptr<torrent> t2 = rhs.associated_torrent().lock();
 		TORRENT_ASSERT(t2);
 
-		// take torrent priority into account
+		if (t1->priority() != t2->priority())
-		c1 *= 1 + t1->priority();
+			return t1->priority() > t2->priority();
-		c2 *= 1 + t2->priority();
 
-		if (c1 > c2) return true;
+		// compare how many bytes they've sent us
-		if (c1 < c2) return false;
+		size_type c1;
+		size_type c2;
+		c1 = m_statistics.total_payload_download() - m_downloaded_at_last_unchoke;
+		c2 = rhs.m_statistics.total_payload_download() - rhs.m_downloaded_at_last_unchoke;
+
+		if (c1 != c2) return c1 > c2;
 
 		if (m_ses.settings().seed_choking_algorithm == session_settings::round_robin)
 		{

src/session_impl.cpp

@@ -3662,7 +3662,7 @@ namespace aux {
 		m_last_choke = now;
 
 		// build list of all peers that are
-		// unchoke:able.
+		// unchokable.
 		std::vector<peer_connection*> peers;
 		for (connection_map::iterator i = m_connections.begin();
 			i != m_connections.end();)