Simplify and improve.

Note - I removed a SleepCurrentThread(1) the patch added which seemed to
be unrelated to the actual job at hand.  If there was a real need for it
(which sounds like it would be an enet-related bug - enet_host_service
is supposed to *sleep*), that needs to be dealt with...

Source/Core/Core/ConfigManager.h

@@ -118,8 +118,6 @@ struct SConfig : NonCopyable
 	bool m_GameCubeAdapter;
 	bool m_AdapterRumble;
 
-	bool m_NetplayDesyncCheck;
-
 	SysConf* m_SYSCONF;
 
 	// Save settings

Source/Core/Core/Movie.cpp

@@ -165,7 +165,7 @@ void FrameUpdate()
 
 	s_bPolled = false;
 
-	if (NetPlay::IsNetPlayRunning() && SConfig::GetInstance().m_NetplayDesyncCheck)
+	if (NetPlay::IsNetPlayRunning())
 		NetPlayClient::SendTimeBase();
 }
 

Source/Core/Core/NetPlayClient.cpp

@@ -374,7 +374,6 @@ unsigned int NetPlayClient::OnData(sf::Packet& packet)
 	case NP_MSG_START_GAME:
 	{
 		{
-			SConfig::GetInstance().m_NetplayDesyncCheck = true;
 			std::lock_guard<std::recursive_mutex> lkg(m_crit.game);
 			packet >> m_current_game;
 			packet >> g_NetPlaySettings.m_CPUthread;
@@ -445,19 +444,21 @@ unsigned int NetPlayClient::OnData(sf::Packet& packet)
 
 	case NP_MSG_DESYNC_DETECTED:
 	{
-		if (!SConfig::GetInstance().m_NetplayDesyncCheck)
-			break;
-
-		int id;
+		int pid_to_blame;
 		u32 frame;
-		packet >> id;
+		packet >> pid_to_blame;
 		packet >> frame;
-		std::string sID = "";
-		if (id != -1)
-			sID = StringFromFormat(" from player ID %d", id);
+		const char* blame_str = "";
+		const char* blame_name = "";
+		std::lock_guard<std::recursive_mutex> lkp(m_crit.players);
+		if (pid_to_blame != -1)
+		{
+			auto it = m_players.find(pid_to_blame);
+			blame_str = " from player ";
+			blame_name = it != m_players.end() ? it->second.name.c_str() : "??";
+		}
 
-		m_dialog->AppendChat("Possible desync detected" + sID + StringFromFormat(" on frame: %u", frame));
-		SConfig::GetInstance().m_NetplayDesyncCheck = false;
+		m_dialog->AppendChat(StringFromFormat("/!\\ Possible desync detected%s%s on frame %u", blame_str, blame_name, frame));
 	}
 	break;
 

Source/Core/Core/NetPlayServer.cpp

@@ -23,8 +23,6 @@
 
 u64 g_netplay_initial_gctime = 1272737767;
 
-static std::map<u32, std::vector<std::pair<u64, u8>>> s_timebase;
-
 NetPlayServer::~NetPlayServer()
 {
 	if (is_connected)
@@ -112,7 +110,7 @@ void NetPlayServer::ThreadFunc()
 	while (m_do_loop)
 	{
 		// update pings every so many seconds
-		if (m_update_pings || (m_ping_timer.GetTimeElapsed() > 1000))
+		if ((m_ping_timer.GetTimeElapsed() > 1000) || m_update_pings)
 		{
 			m_ping_key = Common::Timer::GetTimeMs();
 
@@ -209,7 +207,6 @@ void NetPlayServer::ThreadFunc()
 			break;
 			}
 		}
-		Common::SleepCurrentThread(1);
 	}
 
 	// close listening socket and client sockets
@@ -589,41 +586,44 @@ unsigned int NetPlayServer::OnData(sf::Packet& packet, Client& player)
 		packet >> x;
 		packet >> y;
 		packet >> frame;
-		s_timebase[frame].emplace_back(x | ((u64)y >> 32), player.pid);
 
-		if (!std::all_of(s_timebase[frame].begin(), s_timebase[frame].end(), [&frame](std::pair<u64, u8> i){ return i.first == s_timebase[frame][0].first; }))
+		if (m_desync_detected)
+			break;
+
+		u64 timebase = x | ((u64)y << 32);
+		std::vector<std::pair<PlayerId, u64>>& timebases = m_timebase_by_frame[frame];
+		timebases.emplace_back(player.pid, timebase);
+		if (timebases.size() >= m_players.size())
 		{
-			sf::Packet spac;
-			spac << (MessageId) NP_MSG_DESYNC_DETECTED;
+			// we have all records for this frame
 
-			int pid = -1;
-			if (s_timebase[frame].size() > 2)
+			if (!std::all_of(timebases.begin(), timebases.end(), [&](std::pair<PlayerId, u64> pair){ return pair.second == timebases[0].second; }))
 			{
-				for (auto time : s_timebase[frame])
+				int pid_to_blame = -1;
+				if (timebases.size() > 2)
 				{
-					int count = 0;
-					for (auto _time : s_timebase[frame])
+					for (auto pair : timebases)
 					{
-						if (_time.first == time.first)
-							count++;
-					}
-					if ((size_t)count != s_timebase[frame].size() - 1)
-					{
-						if (pid == -1)
+						if (std::all_of(timebases.begin(), timebases.end(), [&](std::pair<PlayerId, u64> other) {
+							return other.first == pair.first || other.second != pair.second;
+						}))
 						{
-							pid = time.second;
-						}
-						else
-						{
-							pid = -1;
+							// we are the only outlier
+							pid_to_blame = pair.first;
 							break;
 						}
 					}
 				}
+
+				sf::Packet spac;
+				spac << (MessageId) NP_MSG_DESYNC_DETECTED;
+				spac << pid_to_blame;
+				spac << frame;
+				SendToClients(spac);
+
+				m_desync_detected = true;
 			}
-			spac << pid;
-			spac << frame;
-			SendToClients(spac);
+			m_timebase_by_frame.erase(frame);
 		}
 	}
 	break;
@@ -681,7 +681,8 @@ void NetPlayServer::SetNetSettings(const NetSettings &settings)
 // called from ---GUI--- thread
 bool NetPlayServer::StartGame()
 {
-	s_timebase.clear();
+	m_timebase_by_frame.clear();
+	m_desync_detected = false;
 	std::lock_guard<std::recursive_mutex> lkg(m_crit.game);
 	m_current_game = Common::Timer::GetTimeMs();
 

Source/Core/Core/NetPlayServer.h

@@ -9,6 +9,7 @@
 #include <queue>
 #include <sstream>
 #include <thread>
+#include <unordered_map>
 #include <unordered_set>
 #include <SFML/Network/Packet.hpp>
 #include "Common/Timer.h"
@@ -99,6 +100,9 @@ private:
 
 	std::map<PlayerId, Client> m_players;
 
+	std::unordered_map<u32, std::vector<std::pair<PlayerId, u64>>> m_timebase_by_frame;
+	bool m_desync_detected;
+
 	struct
 	{
 		std::recursive_mutex game;