improve queuing logic of inactive torrents (dont_count_slow_torrents)

ChangeLog

@@ -1,5 +1,6 @@
 1.0 release
 
+	* improve queuing logic of inactive torrents (dont_count_slow_torrents)
 	* expose optimistic unchoke logic to plugins
 	* fix issue with large UDP packets on windows
 	* remove set_ratio() feature

include/libtorrent/session_settings.hpp

@@ -1383,6 +1383,15 @@ namespace libtorrent
 		// side effect that the disk cache is less likely and slower at returning
 		// memory to the kernel when cache pressure is low.
 		bool use_disk_cache_pool;
+
+		// the download and upload rate limits for a torrent to be considered
+		// active by the queuing mechanism. A torrent whose download rate is less
+		// than ``inactive_down_rate`` and whose upload rate is less than
+		// ``inactive_up_rate`` for ``auto_manage_startup`` seconds, is
+		// considered inactive, and another queued torrent may be startert.
+		// This logic is disabled if ``dont_count_slow_torrents`` is false.
+		int inactive_down_rate;
+		int inactive_up_rate;
 	};
 
 	// structure used to hold configuration options for the DHT

include/libtorrent/torrent.hpp

@@ -736,6 +736,9 @@ namespace libtorrent
 				- m_picker->num_have() - m_picker->num_filtered() == 0;
 		}
 
+		bool is_inactive() const
+		{ return m_inactive; }
+
 		std::string save_path() const;
 		alert_manager& alerts() const;
 		piece_picker& picker()
@@ -1333,7 +1336,10 @@ namespace libtorrent
 		// set to true while moving the storage
 		bool m_moving_storage:1;
 
-		// TODO: there's space for another bit here
+		// this is true if this torrent is considered inactive from the
+		// queuing mechanism's point of view. If a torrent doesn't transfer
+		// at high enough rates, it's inactive.
+		bool m_inactive:1;
 
 // ----
 
@@ -1402,6 +1408,13 @@ namespace libtorrent
 		// millionths of completeness)
 		unsigned int m_progress_ppm:20;
 
+		// the number of seconds this torrent has been under the inactive
+		// threshold in terms of sending and receiving data. When this counter
+		// reaches the settings.inactive_torrent_timeout it will be considered
+		// inactive and possibly open up another queue slot, to start another,
+		// queued, torrent. Every second it's above the threshold
+		boost::int16_t m_inactive_counter;
+
 #if TORRENT_USE_ASSERTS
 	public:
 		// set to false until we've loaded resume data

src/session.cpp

@@ -1316,7 +1316,7 @@ namespace libtorrent
 		, max_paused_peerlist_size(4000)
 		, min_announce_interval(5 * 60)
 		, prioritize_partial_pieces(false)
-		, auto_manage_startup(120)
+		, auto_manage_startup(60)
 		, rate_limit_ip_overhead(true)
 		, announce_to_all_trackers(false)
 		, announce_to_all_tiers(false)
@@ -1415,6 +1415,8 @@ namespace libtorrent
 		, support_merkle_torrents(false)
 		, report_redundant_bytes(true)
 		, use_disk_cache_pool(false)
+		, inactive_down_rate(2048)
+		, inactive_up_rate(2048)
 	{}
 
 	session_settings::~session_settings() {}

src/session_impl.cpp

@@ -4181,24 +4181,6 @@ retry:
 			m_next_lsd_torrent = m_torrents.begin();
 	}
 
-	namespace
-	{
-		bool is_active(torrent* t, session_settings const& s)
-		{
-			// if we count slow torrents, every torrent
-			// is considered active
-			if (!s.dont_count_slow_torrents) return true;
-			
-			// if the torrent started less than 2 minutes
-			// ago (default), let it count as active since
-			// the rates are probably not accurate yet
-			if (time_now() - t->started() < seconds(s.auto_manage_startup)) return true;
-
-			return t->statistics().upload_payload_rate() != 0.f
-				|| t->statistics().download_payload_rate() != 0.f;
-		}
-	}
-	
 	void session_impl::auto_manage_torrents(std::vector<torrent*>& list
 		, int& dht_limit, int& tracker_limit, int& lsd_limit
 		, int& hard_limit, int type_limit)
@@ -4212,20 +4194,6 @@ retry:
 				|| t->state() == torrent_status::queued_for_checking))
 				continue;
 
-			--dht_limit;
-			--lsd_limit;
-			--tracker_limit;
-			t->set_announce_to_dht(dht_limit >= 0);
-			t->set_announce_to_trackers(tracker_limit >= 0);
-			t->set_announce_to_lsd(lsd_limit >= 0);
-
-			if (!t->is_paused() && !is_active(t, settings())
-				&& hard_limit > 0)
-			{
-				--hard_limit;
-				continue;
-			}
-
 			if (type_limit > 0 && hard_limit > 0)
 			{
 				--hard_limit;
@@ -4234,6 +4202,21 @@ retry:
 				t->log_to_all_peers("AUTO MANAGER STARTING TORRENT");
 #endif
 				t->set_allow_peers(true);
+
+				--dht_limit;
+				--lsd_limit;
+				--tracker_limit;
+				t->set_announce_to_dht(dht_limit >= 0);
+				t->set_announce_to_trackers(tracker_limit >= 0);
+				t->set_announce_to_lsd(lsd_limit >= 0);
+   
+				if (!t->is_paused() && t->is_inactive()
+					&& hard_limit > 0)
+				{
+					// the hard limit takes inactive torrents into account, but the
+					// download and seed limits don't.
+					continue;
+				}
 			}
 			else
 			{

src/torrent.cpp

@@ -232,6 +232,7 @@ namespace libtorrent
 		, m_ssl_torrent(false)
 		, m_deleted(false)
 		, m_moving_storage(false)
+		, m_inactive(false)
 		, m_incomplete(0xffffff)
 		, m_abort(false)
 		, m_announce_to_dht((p.flags & add_torrent_params::flag_paused) == 0)
@@ -247,6 +248,7 @@ namespace libtorrent
 		, m_downloaded(0xffffff)
 		, m_interface_index(0)
 		, m_progress_ppm(0)
+		, m_inactive_counter(0)
 	{
 		// if there is resume data already, we don't need to trigger the initial save
 		// resume data
@@ -7351,6 +7353,8 @@ namespace libtorrent
 		}
 #endif
 
+		m_inactive = false;
+
 		state_updated();
 
 #if defined TORRENT_VERBOSE_LOGGING || defined TORRENT_ERROR_LOGGING || defined TORRENT_LOGGING
@@ -7846,6 +7850,48 @@ namespace libtorrent
 		// if the rate is 0, there's no update because of network transfers
 		if (m_stat.low_pass_upload_rate() > 0 || m_stat.low_pass_download_rate() > 0)
 			state_updated();
+
+		// this section determines whether the torrent is active or not. When it
+		// changes state, it may also trigger the auto-manage logic to reconsider
+		// which torrents should be queued and started. There is a low pass
+		// filter in order to avoid flapping (auto_manage_startup).
+		if (m_stat.download_payload_rate() < m_ses.m_settings.inactive_down_rate
+			&& m_stat.upload_payload_rate() < m_ses.m_settings.inactive_up_rate)
+		{
+			if (m_inactive_counter < 0) m_inactive_counter = 0;
+			if (m_inactive_counter < INT16_MAX)
+			{
+				++m_inactive_counter;
+
+				// if this torrent was just considered inactive, we may want 
+				// to dequeue some other torrent
+				if (m_inactive == false
+					&& m_inactive_counter >= m_ses.m_settings.auto_manage_startup)
+				{
+					m_inactive = true;
+					if (m_ses.m_settings.dont_count_slow_torrents)
+						m_ses.trigger_auto_manage();
+				}
+			}
+		}
+		else
+		{
+			if (m_inactive_counter > 0) m_inactive_counter = 0;
+			if (m_inactive_counter > INT16_MIN)
+			{
+				--m_inactive_counter;
+
+				// if this torrent was just considered active, we may want 
+				// to queue some other torrent
+				if (m_inactive == true
+					&& m_inactive_counter <= -m_ses.m_settings.auto_manage_startup)
+				{
+					m_inactive = false;
+					if (m_ses.m_settings.dont_count_slow_torrents)
+						m_ses.trigger_auto_manage();
+				}
+			}
+		}
 	}
 
 	void torrent::maybe_connect_web_seeds()