optimize setting with unlimited unchoke slots

ChangeLog

@@ -1,3 +1,4 @@
+	* optimize setting with unlimited unchoke slots
 	* fixed restoring of trackers, comment, creation date and created-by in resume data
 	* fix handling of torrents with too large pieces
 	* fixed division by zero in anti-leech choker

include/libtorrent/settings_pack.hpp

@@ -1358,7 +1358,8 @@ namespace aux {
 
 			// ``unchoke_slots_limit`` is the max number of unchoked peers in the
 			// session. The number of unchoke slots may be ignored depending on
-			// what ``choking_algorithm`` is set to.
+			// what ``choking_algorithm`` is set to. Setting this limit to -1
+			// means unlimited, i.e. all peers will always be unchoked.
 			unchoke_slots_limit,
 
 #if TORRENT_ABI_VERSION == 1

src/session.cpp

@@ -205,8 +205,8 @@ namespace {
 		// allow lots of peers to try to connect simultaneously
 		set.set_int(settings_pack::listen_queue_size, 3000);
 
-		// unchoke many peers
-		set.set_int(settings_pack::unchoke_slots_limit, 2000);
+		// unchoke all peers
+		set.set_int(settings_pack::unchoke_slots_limit, -1);
 
 		// use 1 GB of cache
 		set.set_int(settings_pack::cache_size, 32768 * 2);

src/session_impl.cpp

@@ -3909,6 +3909,9 @@ namespace aux {
 		TORRENT_ASSERT(is_single_thread());
 		if (m_stats_counters[counters::num_unchoke_slots] == 0) return;
 
+		// if we unchoke everyone, skip this logic
+		if (settings().get_int(settings_pack::unchoke_slots_limit) < 0) return;
+
 		std::vector<opt_unchoke_candidate> opt_unchoke;
 
 		// collect the currently optimistically unchoked peers here, so we can
@@ -4174,6 +4177,13 @@ namespace aux {
 		time_duration const unchoke_interval = now - m_last_choke;
 		m_last_choke = now;
 
+		// if we unchoke everyone, skip this logic
+		if (settings().get_int(settings_pack::unchoke_slots_limit) < 0)
+		{
+			m_stats_counters.set_value(counters::num_unchoke_slots, std::numeric_limits<int>::max());
+			return;
+		}
+
 		// build list of all peers that are
 		// unchokable.
 		// TODO: 3 there should be a pre-calculated list of all peers eligible for
@@ -6298,6 +6308,25 @@ namespace aux {
 				m_alerts.emplace_alert<performance_alert>(torrent_handle()
 					, performance_alert::too_many_optimistic_unchoke_slots);
 		}
+
+		if (allowed_upload_slots == std::numeric_limits<int>::max())
+		{
+			// this means we're not aplpying upload slot limits, unchoke
+			// everyone
+			for (auto const& p : m_connections)
+			{
+				if (p->is_disconnecting() || p->is_connecting())
+					continue;
+
+				auto const t = p->associated_torrent().lock();
+				t->unchoke_peer(*p);
+			}
+		}
+		else
+		{
+			// trigger recalculating unchoke slots
+			m_unchoke_time_scaler = 0;
+		}
 	}
 
 	void session_impl::update_connection_speed()