improved auto-unchoke mechanism

include/libtorrent/torrent.hpp

@@ -248,6 +248,8 @@ namespace libtorrent
 		int max_assignable_bandwidth(int channel) const
 		{ return m_bandwidth_limit[channel].max_assignable(); }
 
+		int bandwidth_queue_size(int channel) const;
+
 // --------------------------------------------
 		// PEER MANAGEMENT
 		

src/session_impl.cpp

@@ -1340,6 +1340,8 @@ namespace detail
 			c.keep_alive();
 		}
 
+		int congested_torrents = 0;
+		int uncongested_torrents = 0;
 		// check each torrent for tracker updates
 		// TODO: do this in a timer-event in each torrent instead
 		for (torrent_map::iterator i = m_torrents.begin();
@@ -1347,6 +1349,11 @@ namespace detail
 		{
 			torrent& t = *i->second;
 			TORRENT_ASSERT(!t.is_aborted());
+			if (t.bandwidth_queue_size(peer_connection::upload_channel))
+				++congested_torrents;
+			else
+				++uncongested_torrents;
+
 			if (t.should_request())
 			{
 				tracker_request req = t.generate_tracker_request();
@@ -1427,8 +1434,12 @@ namespace detail
 			if (m_settings.auto_upload_slots && upload_limit != bandwidth_limit::inf)
 			{
 				// if our current upload rate is less than 90% of our 
+ 				// limit AND most torrents are not "congested", i.e.
+ 				// they are not holding back because of a per-torrent
+ 				// limit
 				if (m_stat.upload_rate() < upload_limit * 0.9f
-					&& m_allowed_upload_slots < m_num_unchoked + 2)
+					&& m_allowed_upload_slots <= m_num_unchoked + 1
+ 					&& congested_torrents < uncongested_torrents)
 				{
 					++m_allowed_upload_slots;
 				}
@@ -2235,8 +2246,9 @@ namespace detail
 		INVARIANT_CHECK;
 
 		if (limit <= 0) limit = (std::numeric_limits<int>::max)();
+		if (m_max_uploads == limit) return;
 		m_max_uploads = limit;
-		if (m_allowed_upload_slots < limit) m_allowed_upload_slots = limit;
+		m_allowed_upload_slots = limit;
 	}
 
 	void session_impl::set_max_connections(int limit)

src/torrent.cpp

@@ -2271,6 +2271,11 @@ namespace libtorrent
 		return m_bandwidth_limit[channel].throttle();
 	}
 
+	int torrent::bandwidth_queue_size(int channel) const
+	{
+		return (int)m_bandwidth_queue[channel].size();
+	}
+
 	void torrent::request_bandwidth(int channel
 		, boost::intrusive_ptr<peer_connection> const& p
 		, bool non_prioritized, int max_block_size)

test/Jamfile

@@ -23,6 +23,7 @@ project
 
 
 test-suite libtorrent : 
+	[ run test_auto_unchoke.cpp ]
 	[ run test_http_connection.cpp ]
 	[ run test_buffer.cpp ]
 	[ run test_storage.cpp ]

test/test_auto_unchoke.cpp

@@ -0,0 +1,122 @@
+#include "libtorrent/session.hpp"
+#include "libtorrent/session_settings.hpp"
+#include "libtorrent/hasher.hpp"
+#include "libtorrent/alert_types.hpp"
+#include <boost/thread.hpp>
+#include <boost/tuple/tuple.hpp>
+#include <boost/filesystem/operations.hpp>
+
+#include "test.hpp"
+#include "setup_transfer.hpp"
+
+using boost::filesystem::remove_all;
+using boost::filesystem::exists;
+
+void test_swarm()
+{
+	using namespace libtorrent;
+
+	session ses1(fingerprint("LT", 0, 1, 0, 0), std::make_pair(48010, 49000));
+	session ses2(fingerprint("LT", 0, 1, 0, 0), std::make_pair(49010, 50000));
+	session ses3(fingerprint("LT", 0, 1, 0, 0), std::make_pair(50010, 51000));
+
+	ses1.set_severity_level(alert::debug);
+	ses2.set_severity_level(alert::debug);
+	ses3.set_severity_level(alert::debug);
+	
+	// this is to avoid everything finish from a single peer
+	// immediately. To make the swarm actually connect all
+	// three peers before finishing.
+	float rate_limit = 100000;
+	ses1.set_upload_rate_limit(int(rate_limit));
+	ses1.set_max_uploads(1);
+	ses2.set_download_rate_limit(int(rate_limit / 5));
+	ses3.set_download_rate_limit(int(rate_limit / 5));
+	ses2.set_upload_rate_limit(int(rate_limit / 10));
+	ses3.set_upload_rate_limit(int(rate_limit / 10));
+
+	session_settings settings;
+	settings.allow_multiple_connections_per_ip = true;
+	settings.ignore_limits_on_local_network = false;
+	ses1.set_settings(settings);
+	ses2.set_settings(settings);
+	ses3.set_settings(settings);
+
+#ifndef TORRENT_DISABLE_ENCRYPTION
+	pe_settings pes;
+	pes.out_enc_policy = pe_settings::forced;
+	pes.in_enc_policy = pe_settings::forced;
+	ses1.set_pe_settings(pes);
+	ses2.set_pe_settings(pes);
+	ses3.set_pe_settings(pes);
+#endif
+
+	torrent_handle tor1;
+	torrent_handle tor2;
+	torrent_handle tor3;
+
+	boost::tie(tor1, tor2, tor3) = setup_transfer(&ses1, &ses2, &ses3, true, false, true, "_unchoke");	
+
+	session_status st = ses1.status();
+	TEST_CHECK(st.allowed_upload_slots == 1);
+	for (int i = 0; i < 50; ++i)
+	{
+		print_alerts(ses1, "ses1");
+		print_alerts(ses2, "ses2");
+		print_alerts(ses3, "ses3");
+
+		st = ses1.status();
+		if (st.allowed_upload_slots >= 2) break;
+
+		torrent_status st1 = tor1.status();
+		torrent_status st2 = tor2.status();
+		torrent_status st3 = tor3.status();
+
+		std::cerr
+			<< "\033[33m" << int(st1.upload_payload_rate / 1000.f) << "kB/s "
+			<< st1.num_peers << " " << st.allowed_upload_slots << ": "
+			<< "\033[32m" << int(st2.download_payload_rate / 1000.f) << "kB/s "
+			<< "\033[31m" << int(st2.upload_payload_rate / 1000.f) << "kB/s "
+			<< "\033[0m" << int(st2.progress * 100) << "% "
+			<< st2.num_peers << " - "
+			<< "\033[32m" << int(st3.download_payload_rate / 1000.f) << "kB/s "
+			<< "\033[31m" << int(st3.upload_payload_rate / 1000.f) << "kB/s "
+			<< "\033[0m" << int(st3.progress * 100) << "% "
+			<< st3.num_peers
+			<< std::endl;
+
+		test_sleep(1000);
+	}
+
+	TEST_CHECK(st.allowed_upload_slots == 2);
+
+	// make sure the files are deleted
+	ses1.remove_torrent(tor1, session::delete_files);
+	ses2.remove_torrent(tor2, session::delete_files);
+	ses3.remove_torrent(tor3, session::delete_files);
+}
+
+int test_main()
+{
+	using namespace libtorrent;
+	using namespace boost::filesystem;
+
+	// in case the previous run was terminated
+	try { remove_all("./tmp1_unchoke"); } catch (std::exception&) {}
+	try { remove_all("./tmp2_unchoke"); } catch (std::exception&) {}
+	try { remove_all("./tmp3_unchoke"); } catch (std::exception&) {}
+
+	test_swarm();
+	
+	test_sleep(2000);
+	TEST_CHECK(!exists("./tmp1_unchoke/temporary"));
+	TEST_CHECK(!exists("./tmp2_unchoke/temporary"));
+	TEST_CHECK(!exists("./tmp3_unchoke/temporary"));
+
+	remove_all("./tmp1_unchoke");
+	remove_all("./tmp2_unchoke");
+	remove_all("./tmp3_unchoke");
+
+	return 0;
+}
+