From f31e670fc2fc793df604416c8a6835ebde0d0c84 Mon Sep 17 00:00:00 2001
From: Arvid Norberg <arvid@libtorrent.org>
Date: Thu, 18 Feb 2010 17:26:21 +0000
Subject: [PATCH] made end-game mode less aggressive

---
 ChangeLog                           |  1 +
 include/libtorrent/piece_picker.hpp |  5 ++++-
 src/piece_picker.cpp                | 19 +++++++++++++++++++
 src/policy.cpp                      | 17 ++++++++++++++++-
 4 files changed, 40 insertions(+), 2 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index f492f12a1..6bd059c9a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -119,6 +119,7 @@ release 0.14.9
 	* fixed DHT bootstrapping issue
 	* fixed UDP over SOCKS5 issue
 	* added support for "corrupt" tracker announce
+	* made end-game mode less aggressive
 
 release 0.14.8
 
diff --git a/include/libtorrent/piece_picker.hpp b/include/libtorrent/piece_picker.hpp
index 082fefe23..f08d1b743 100644
--- a/include/libtorrent/piece_picker.hpp
+++ b/include/libtorrent/piece_picker.hpp
@@ -52,6 +52,7 @@ POSSIBILITY OF SUCH DAMAGE.
 #include "libtorrent/session_settings.hpp"
 #include "libtorrent/config.hpp"
 #include "libtorrent/assert.hpp"
+#include "libtorrent/time.hpp"
 
 namespace libtorrent
 {
@@ -139,8 +140,9 @@ namespace libtorrent
 
 		struct downloading_piece
 		{
-			downloading_piece(): finished(0), writing(0), requested(0) {}
+			downloading_piece(): last_request(min_time()), finished(0), writing(0), requested(0) {}
 			piece_state_t state;
+			ptime last_request;
 
 			// the index of the piece
 			int index;
@@ -278,6 +280,7 @@ namespace libtorrent
 		void mark_as_finished(piece_block block, void* peer);
 		void write_failed(piece_block block);
 		int num_peers(piece_block block) const;
+		ptime last_request(int piece) const;
 
 		// returns information about the given piece
 		void piece_info(int index, piece_picker::downloading_piece& st) const;
diff --git a/src/piece_picker.cpp b/src/piece_picker.cpp
index b50f2ccbe..407e88c62 100644
--- a/src/piece_picker.cpp
+++ b/src/piece_picker.cpp
@@ -2012,6 +2012,7 @@ namespace libtorrent
 			info.peer = peer;
 			info.num_peers = 1;
 			++dp.requested;
+			dp.last_request = time_now();
 		}
 		else
 		{
@@ -2036,6 +2037,7 @@ namespace libtorrent
 			}
 			++info.num_peers;
 			if (i->state == none) i->state = state;
+			i->last_request = time_now();
 		}
 		return true;
 	}
@@ -2058,6 +2060,23 @@ namespace libtorrent
 		return info.num_peers;
 	}
 
+	ptime piece_picker::last_request(int piece) const
+	{
+		TORRENT_ASSERT(piece >= 0);
+		TORRENT_ASSERT(piece < (int)m_piece_map.size());
+
+		piece_pos const& p = m_piece_map[piece];
+		if (!p.downloading) return min_time();
+
+		std::vector<downloading_piece>::const_iterator i
+			= std::find_if(m_downloads.begin(), m_downloads.end(), has_index(piece));
+		TORRENT_ASSERT(i != m_downloads.end());
+		// just to play it safe
+		if (i == m_downloads.end()) return min_time();
+
+		return i->last_request;
+	}
+
 	void piece_picker::get_availability(std::vector<int>& avail) const
 	{
 		TORRENT_ASSERT(m_seeds >= 0);
diff --git a/src/policy.cpp b/src/policy.cpp
index 2804ee7ca..5fd1352aa 100644
--- a/src/policy.cpp
+++ b/src/policy.cpp
@@ -264,7 +264,13 @@ namespace libtorrent
 			num_requests--;
 		}
 
-		if (busy_pieces.empty() || num_requests <= 0)
+		// if we don't have any potential busy blocks to request
+		// or if we have picked as many blocks as we should
+		// or if we already have outstanding requests, don't
+		// pick a busy piece
+		if (busy_pieces.empty()
+			|| num_requests <= 0
+			|| dq.size() + rq.size() > 0)
 		{
 			return;
 		}
@@ -285,6 +291,15 @@ namespace libtorrent
 #endif
 		TORRENT_ASSERT(p.is_requested(*i));
 		TORRENT_ASSERT(p.num_peers(*i) > 0);
+
+		ptime last_request = p.last_request(i->piece_index);
+		ptime now = time_now();
+
+		// don't re-request from a piece more often than once every 20 seconds
+		// TODO: make configurable
+		if (now - last_request < seconds(20))
+			return;
+
 		c.add_request(*i, peer_connection::req_busy);
 	}