made the unchoke interval configurable

include/libtorrent/policy.hpp

@@ -104,6 +104,8 @@ namespace libtorrent
 		// the peer choked us
 		void choked(peer_connection& c);
 
+		int count_choked() const;
+
 		// the peer unchoked us
 		void unchoked(peer_connection& c);
 

include/libtorrent/session_settings.hpp

@@ -105,6 +105,7 @@ namespace libtorrent
 			, send_redundant_have(false)
 			, lazy_bitfields(true)
 			, inactivity_timeout(600)
+			, unchoke_interval(20)
 #ifndef TORRENT_DISABLE_DHT
 			, use_dht_as_fallback(true)
 #endif
@@ -234,6 +235,9 @@ namespace libtorrent
 		// default is 10 minutes
 		int inactivity_timeout;
 
+		// the number of seconds between chokes/unchokes
+		int unchoke_interval;
+
 #ifndef TORRENT_DISABLE_DHT
 		// while this is true, the dht will note be used unless the
 		// tracker is online

src/policy.cpp

@@ -850,12 +850,13 @@ namespace libtorrent
 						--m_num_unchoked;
 					} while (m_num_unchoked > m_torrent->m_uploads_quota.given);
 				}
-				else
+				// this should prevent the choke/unchoke
+				// problem, since it will not unchoke unless
+				// there actually are any choked peers
+				else if (count_choked() > 0)
 				{
 					// optimistic unchoke. trade the 'worst'
 					// unchoked peer with one of the choked
-					// TODO: This rotation should happen
-					// far less frequent than this!
 					assert(m_num_unchoked <= m_torrent->num_peers());
 					iterator p = find_unchoke_candidate();
 					if (p != m_peers.end())
@@ -875,6 +876,22 @@ namespace libtorrent
 		}
 	}
 
+	int policy::count_choked() const
+	{
+		int ret = 0;
+		for (const_iterator i = m_peers.begin();
+			i != m_peers.end(); ++i)
+		{
+			if (!i->connection
+				|| i->connection->is_connecting()
+				|| i->connection->is_disconnecting()
+				|| !i->connection->is_peer_interested())
+				continue;
+			if (i->connection->is_choked()) ++ret;
+		}
+		return ret;
+	}
+
 	void policy::new_connection(peer_connection& c)
 	{
 		assert(!c.is_local());

src/session_impl.cpp

@@ -623,6 +623,9 @@ namespace libtorrent { namespace detail
 		mutex_t::scoped_lock l(m_mutex);
 		assert(s.connection_speed > 0);
 		assert(s.file_pool_size > 0);
+
+		// less than 5 seconds unchoke interval is insane
+		assert(s.unchoke_interval >= 5);
 		m_settings = s;
 		m_files.resize(m_settings.file_pool_size);
 		// replace all occurances of '\n' with ' '.

src/torrent.cpp

@@ -562,7 +562,6 @@ namespace libtorrent
 					bind(&torrent::on_peer_name_lookup, shared_from_this(), _1, _2, i->pid)));
 			}	
 		}
-		m_policy->pulse();
 
 		if (m_ses.m_alerts.should_post(alert::info))
 		{
@@ -2464,7 +2463,7 @@ namespace libtorrent
 		m_time_scaler--;
 		if (m_time_scaler <= 0)
 		{
-			m_time_scaler = 10;
+			m_time_scaler = settings().unchoke_interval;
 			m_policy->pulse();
 		}
 	}