Network: Extend post-desync frame sync history

Record sync state at various points throughout each frame

src/crashlog.cpp

@@ -638,8 +638,8 @@ char *CrashLog::FillDesyncCrashLog(char *buffer, const char *last, const DesyncE
 				flag_check(DesyncExtraInfo::DEIF_RAND, "R"),
 				flag_check(DesyncExtraInfo::DEIF_STATE, "S"));
 	}
-	if (_network_server && (info.desync_frame_seed || info.desync_frame_state_checksum)) {
-		buffer += seprintf(buffer, last, "Desync frame: %08X (seed), %08X (state checksum)\n", info.desync_frame_seed, info.desync_frame_state_checksum);
+	if (_network_server && !info.desync_frame_info.empty()) {
+		buffer += seprintf(buffer, last, "%s\n", info.desync_frame_info.c_str());
 	}
 
 	extern uint32 _frame_counter;

src/crashlog.h

@@ -28,8 +28,7 @@ struct DesyncExtraInfo {
 	Flags flags = DEIF_NONE;
 	const char *client_name = nullptr;
 	int client_id = -1;
-	uint32 desync_frame_seed = 0;
-	uint32 desync_frame_state_checksum = 0;
+	std::string desync_frame_info;
 	FILE **log_file = nullptr; ///< save unclosed log file handle here
 	DesyncDeferredSaveInfo *defer_savegame_write = nullptr;
 };

src/landscape.cpp

@@ -36,6 +36,7 @@
 #include "3rdparty/cpp-btree/btree_set.h"
 #include "scope_info.h"
 #include "core/ring_buffer.hpp"
+#include "network/network_sync.h"
 #include <array>
 #include <list>
 #include <set>
@@ -786,6 +787,7 @@ void RunTileLoop(bool apply_day_length)
 	}
 
 	_cur_tileloop_tile = tile;
+	RecordSyncEvent(NSRE_TILE);
 }
 
 void RunAuxiliaryTileLoop()
@@ -813,6 +815,7 @@ void RunAuxiliaryTileLoop()
 	}
 
 	_aux_tileloop_tile = tile;
+	RecordSyncEvent(NSRE_AUX_TILE);
 }
 
 void InitializeLandscape()
@@ -1627,9 +1630,13 @@ void CallLandscapeTick()
 		PerformanceAccumulator framerate(PFE_GL_LANDSCAPE);
 
 		OnTick_Town();
+		RecordSyncEvent(NSRE_TOWN);
 		OnTick_Trees();
+		RecordSyncEvent(NSRE_TREE);
 		OnTick_Station();
+		RecordSyncEvent(NSRE_STATION);
 		OnTick_Industry();
+		RecordSyncEvent(NSRE_INDUSTRY);
 	}
 
 	OnTick_LinkGraph();

src/network/CMakeLists.txt

@@ -30,6 +30,7 @@ add_files(
     network_stun.h
     network_survey.cpp
     network_survey.h
+    network_sync.h
     network_turn.cpp
     network_turn.h
     network_type.h

src/network/network.cpp

@@ -90,9 +90,9 @@ uint32 _last_sync_frame_counter;      ///< "
 bool _network_first_time;             ///< Whether we have finished joining or not.
 CompanyMask _network_company_passworded; ///< Bitmask of the password status of all companies.
 
-std::vector<NetworkSyncRecord> _network_client_sync_records;
-std::unique_ptr<std::array<NetworkSyncRecord, 1024>> _network_server_sync_records;
-uint32 _network_server_sync_records_next;
+ring_buffer<NetworkSyncRecord> _network_sync_records;
+ring_buffer<uint> _network_sync_record_counts;
+bool _record_sync_records = false;
 
 static_assert((int)NETWORK_COMPANY_NAME_LENGTH == MAX_LENGTH_COMPANY_NAME_CHARS * MAX_CHAR_LENGTH);
 
@@ -674,9 +674,10 @@ void NetworkClose(bool close_admins)
 
 	InitializeNetworkPools(close_admins);
 
-	_network_client_sync_records.clear();
-	_network_client_sync_records.shrink_to_fit();
-	_network_server_sync_records.reset();
+	_network_sync_records.clear();
+	_network_sync_records.shrink_to_fit();
+	_network_sync_record_counts.clear();
+	_network_sync_record_counts.shrink_to_fit();
 }
 
 /* Initializes the network (cleans sockets and stuff) */
@@ -968,9 +969,9 @@ bool NetworkServerStart()
 	_last_sync_frame = 0;
 	_network_own_client_id = CLIENT_ID_SERVER;
 
-	_network_server_sync_records.reset(new std::array<NetworkSyncRecord, 1024>());
-	_network_server_sync_records->fill({ 0, 0, 0 });
-	_network_server_sync_records_next = 0;
+	_network_sync_records.clear();
+	_network_sync_record_counts.clear();
+	_record_sync_records = false;
 
 	_network_clients_connected = 0;
 	_network_company_passworded = 0;
@@ -1111,6 +1112,42 @@ void NetworkBackgroundLoop()
 	NetworkBackgroundUDPLoop();
 }
 
+void RecordSyncEventData(NetworkSyncRecordEvents event)
+{
+	_network_sync_records.push_back({ event, _random.state[0], _state_checksum.state });
+}
+
+const char *GetSyncRecordEventName(NetworkSyncRecordEvents event)
+{
+	static const char *names[] = {
+		"BEGIN",
+		"CMD",
+		"AUX_TILE",
+		"TILE",
+		"TOWN",
+		"TREE",
+		"STATION",
+		"INDUSTRY",
+		"PRE_COMPANY_STATE",
+		"VEH_PERIODIC",
+		"VEH_LOAD_UNLOAD",
+		"VEH_EFFECT",
+		"VEH_TRAIN",
+		"VEH_ROAD",
+		"VEH_AIR",
+		"VEH_SHIP",
+		"VEH_OTHER",
+		"VEH_SELL",
+		"VEH_TBTR",
+		"VEH_AUTOREPLACE",
+		"VEH_REPAIR",
+		"FRAME_DONE"
+	};
+	static_assert(lengthof(names) == NSRE_LAST);
+	if (event < NSRE_LAST) return names[event];
+	return "???";
+}
+
 /* The main loop called from ttd.c
  *  Here we also have to do StateGameLoop if needed! */
 void NetworkGameLoop()
@@ -1254,6 +1291,10 @@ void NetworkGameLoop()
 			send_frame = true;
 		}
 
+		const size_t total_sync_records = _network_sync_records.size();
+		_network_sync_records.push_back({ _frame_counter, _random.state[0], _state_checksum.state });
+		_record_sync_records = true;
+
 		NetworkExecuteLocalCommandQueue();
 		if (_pause_countdown > 0 && --_pause_countdown == 0) DoCommandP(0, PM_PAUSED_NORMAL, 1, CMD_PAUSE);
 
@@ -1263,8 +1304,14 @@ void NetworkGameLoop()
 		_sync_seed_1 = _random.state[0];
 		_sync_state_checksum = _state_checksum.state;
 
-		(*_network_server_sync_records)[_network_server_sync_records_next] = { _frame_counter, _random.state[0], _state_checksum.state };
-		_network_server_sync_records_next = (_network_server_sync_records_next + 1) % _network_server_sync_records->size();
+		_network_sync_records.push_back({ NSRE_FRAME_DONE, _random.state[0], _state_checksum.state });
+		_network_sync_record_counts.push_back((uint)(_network_sync_records.size() - total_sync_records));
+		_record_sync_records = false;
+		if (_network_sync_record_counts.size() >= 256) {
+			/* Remove records from start of queue */
+			_network_sync_records.erase(_network_sync_records.begin(), _network_sync_records.begin() + _network_sync_record_counts[0]);
+			_network_sync_record_counts.pop_front();
+		}
 
 		NetworkServer_Tick(send_frame);
 	} else {

src/network/network_client.cpp

@@ -309,10 +309,18 @@ void ClientNetworkGameSocketHandler::ClientError(NetworkRecvStatus res)
 {
 	_frame_counter++;
 
+	const size_t total_sync_records = _network_sync_records.size();
+	_network_sync_records.push_back({ _frame_counter, _random.state[0], _state_checksum.state });
+	_record_sync_records = true;
+
 	NetworkExecuteLocalCommandQueue();
 
 	StateGameLoop();
 
+	_network_sync_records.push_back({ NSRE_FRAME_DONE, _random.state[0], _state_checksum.state });
+	_network_sync_record_counts.push_back((uint)(_network_sync_records.size() - total_sync_records));
+	_record_sync_records = false;
+
 	/* Check if we are in sync! */
 	if (_sync_frame != 0) {
 		if (_sync_frame == _frame_counter) {
@@ -341,7 +349,8 @@ void ClientNetworkGameSocketHandler::ClientError(NetworkRecvStatus res)
 			_last_sync_date_fract = _date_fract;
 			_last_sync_tick_skip_counter = _tick_skip_counter;
 			_last_sync_frame_counter = _sync_frame;
-			_network_client_sync_records.clear();
+			_network_sync_records.clear();
+			_network_sync_record_counts.clear();
 
 			/* If this is the first time we have a sync-frame, we
 			 *   need to let the server know that we are ready and at the same
@@ -358,8 +367,10 @@ void ClientNetworkGameSocketHandler::ClientError(NetworkRecvStatus res)
 		}
 	}
 
-	if (_network_client_sync_records.size() <= 256) {
-		_network_client_sync_records.push_back({ _frame_counter, _random.state[0], _state_checksum.state });
+	if (_network_sync_record_counts.size() >= 128) {
+		/* Remove records from start of queue */
+		_network_sync_records.erase(_network_sync_records.begin(), _network_sync_records.begin() + _network_sync_record_counts[0]);
+		_network_sync_record_counts.pop_front();
 	}
 
 	return true;
@@ -632,14 +643,30 @@ NetworkRecvStatus ClientNetworkGameSocketHandler::SendDesyncMessage(const char *
 /** Send an error-packet over the network */
 NetworkRecvStatus ClientNetworkGameSocketHandler::SendDesyncSyncData()
 {
-	if (_network_client_sync_records.empty()) return NETWORK_RECV_STATUS_OKAY;
+	if (_network_sync_record_counts.empty()) return NETWORK_RECV_STATUS_OKAY;
+
+	uint total = 0;
+	for (uint32 count : _network_sync_record_counts) {
+		total += count;
+	}
+
+	if ((size_t)total != _network_sync_records.size()) {
+		DEBUG(net, 0, "Network sync record error");
+		return NETWORK_RECV_STATUS_OKAY;
+	}
 
 	Packet *p = new Packet(PACKET_CLIENT_DESYNC_SYNC_DATA, SHRT_MAX);
-	p->Send_uint32(_network_client_sync_records[0].frame);
-	p->Send_uint32((uint)_network_client_sync_records.size());
-	for (uint i = 0; i < (uint)_network_client_sync_records.size(); i++) {
-		p->Send_uint32(_network_client_sync_records[i].seed_1);
-		p->Send_uint64(_network_client_sync_records[i].state_checksum);
+	p->Send_uint32((uint32)_network_sync_record_counts.size());
+	uint32 offset = 0;
+	for (uint32 count : _network_sync_record_counts) {
+		p->Send_uint32(count);
+		for (uint i = 0; i < count; i++) {
+			const NetworkSyncRecord &record = _network_sync_records[offset + i];
+			p->Send_uint32(record.frame);
+			p->Send_uint32(record.seed_1);
+			p->Send_uint64(record.state_checksum);
+		}
+		offset += count;
 	}
 	my_client->SendPacket(p);
 	return NETWORK_RECV_STATUS_OKAY;

src/network/network_command.cpp

@@ -214,6 +214,7 @@ void NetworkExecuteLocalCommandQueue()
 
 	CommandQueue &queue = (_network_server ? _local_execution_queue : ClientNetworkGameSocketHandler::my_client->incoming_queue);
 
+	bool record_sync_event = false;
 	CommandPacket *cp;
 	while ((cp = queue.Peek()) != nullptr) {
 		/* The queue is always in order, which means
@@ -233,11 +234,15 @@ void NetworkExecuteLocalCommandQueue()
 		DoCommandP(cp, cp->my_cmd);
 
 		queue.Pop();
+
+		record_sync_event = true;
 	}
 
 	/* Local company may have changed, so we should not restore the old value */
 	_current_company = _local_company;
 	_cmd_client_id = INVALID_CLIENT_ID;
+
+	if (record_sync_event) RecordSyncEvent(NSRE_CMD);
 }
 
 /**

src/network/network_internal.h

@@ -11,6 +11,7 @@
 #define NETWORK_INTERNAL_H
 
 #include "network_func.h"
+#include "network_sync.h"
 #include "core/tcp_coordinator.h"
 #include "core/tcp_game.h"
 
@@ -18,8 +19,6 @@
 #include "../date_type.h"
 
 #include <vector>
-#include <array>
-#include <memory>
 
 static const uint32 FIND_SERVER_EXTENDED_TOKEN = 0x2A49582A;
 
@@ -96,16 +95,6 @@ extern uint8 _network_reconnect;
 
 extern CompanyMask _network_company_passworded;
 
-/* Sync debugging */
-struct NetworkSyncRecord {
-	uint32 frame;
-	uint32 seed_1;
-	uint64 state_checksum;
-};
-extern std::vector<NetworkSyncRecord> _network_client_sync_records;
-extern std::unique_ptr<std::array<NetworkSyncRecord, 1024>> _network_server_sync_records;
-extern uint32 _network_server_sync_records_next;
-
 void NetworkQueryServer(const std::string &connection_string);
 
 void GetBindAddresses(NetworkAddressList *addresses, uint16 port);

src/network/network_server.cpp

@@ -1291,8 +1291,7 @@ NetworkRecvStatus ServerNetworkGameSocketHandler::Receive_CLIENT_ERROR(Packet *p
 		DesyncExtraInfo info;
 		info.client_name = client_name;
 		info.client_id = this->client_id;
-		info.desync_frame_seed = this->desync_frame_seed;
-		info.desync_frame_state_checksum = this->desync_frame_state_checksum;
+		info.desync_frame_info = std::move(this->desync_frame_info);
 		CrashLog::DesyncCrashLog(&(this->desync_log), &server_desync_log, info);
 		this->SendDesyncLog(server_desync_log);
 
@@ -1336,32 +1335,58 @@ NetworkRecvStatus ServerNetworkGameSocketHandler::Receive_CLIENT_DESYNC_MSG(Pack
 
 NetworkRecvStatus ServerNetworkGameSocketHandler::Receive_CLIENT_DESYNC_SYNC_DATA(Packet *p)
 {
-	uint32 frame = p->Recv_uint32();
-	uint32 count = p->Recv_uint32();
-
-	DEBUG(net, 2, "Received desync sync data: %u frames from %08X", count, frame);
+	uint32 frame_count = p->Recv_uint32();
+
+	DEBUG(net, 2, "Received desync sync data: %u frames", frame_count);
+
+	if (frame_count == 0 || _network_sync_record_counts.empty()) return NETWORK_RECV_STATUS_OKAY;
+
+	size_t record_count_offset = 0;
+	size_t record_offset = 0;
+	for (uint i = 0; i < frame_count; i++) {
+		uint32 item_count = p->Recv_uint32();
+		if (item_count == 0) continue;
+		uint32 local_item_count = 0;
+		uint32 frame = 0;
+		NetworkSyncRecordEvents event = NSRE_BEGIN;
+		for (uint j = 0; j < item_count; j++) {
+			if (j == 0) {
+				frame = p->Recv_uint32();
+				while (_network_sync_records[record_offset].frame != frame) {
+					if (record_count_offset == _network_sync_record_counts.size()) {
+						return NETWORK_RECV_STATUS_OKAY;
+					}
+					record_offset += _network_sync_record_counts[record_count_offset];
+					record_count_offset++;
+				}
+				local_item_count = _network_sync_record_counts[record_count_offset];
+			} else {
+				event = (NetworkSyncRecordEvents)p->Recv_uint32();
+			}
+			uint32 seed_1 = p->Recv_uint32();
+			uint64 state_checksum = p->Recv_uint64();
+			if (j == local_item_count) {
+				this->desync_frame_info = stdstr_fmt("Desync subframe count mismatch: extra client record: %08X, %s", frame, GetSyncRecordEventName(event));
+				return NETWORK_RECV_STATUS_OKAY;
+			}
 
-	uint server_idx = UINT32_MAX;
-	for (uint i = 0; i < _network_server_sync_records->size(); i++) {
-		if ((*_network_server_sync_records)[i].frame == frame) {
-			server_idx = i;
-			break;
+			const NetworkSyncRecord &record = _network_sync_records[record_offset + j];
+			if (j != 0 && record.frame != event) {
+				this->desync_frame_info = stdstr_fmt("Desync subframe event mismatch: %08X, client: %s != server: %s",
+						frame, GetSyncRecordEventName(event), GetSyncRecordEventName((NetworkSyncRecordEvents)record.frame));
+				return NETWORK_RECV_STATUS_OKAY;
+			}
+			if (seed_1 != record.seed_1 || state_checksum != record.state_checksum) {
+				this->desync_frame_info = stdstr_fmt("Desync subframe mismatch: %08X, %s%s%s",
+						frame, GetSyncRecordEventName(event), (seed_1 != record.seed_1) ? ", seed" : "", (state_checksum != record.state_checksum) ? ", state checksum" : "");
+				return NETWORK_RECV_STATUS_OKAY;
+			}
+		}
+		if (local_item_count > item_count) {
+			const NetworkSyncRecord &record = _network_sync_records[record_offset + item_count];
+			this->desync_frame_info = stdstr_fmt("Desync subframe count mismatch: extra server record: %08X, %s", frame, GetSyncRecordEventName((NetworkSyncRecordEvents)record.frame));
+			return NETWORK_RECV_STATUS_OKAY;
 		}
-	}
-	if (server_idx == UINT32_MAX) return NETWORK_RECV_STATUS_OKAY;
-
-	for (uint i = 0; i < count; i++) {
-		uint32 seed_1 = p->Recv_uint32();
-		uint64 state_checksum = p->Recv_uint64();
-
-		const NetworkSyncRecord &record = (*_network_server_sync_records)[server_idx];
-
-		if (record.frame != frame) break;
-		if (record.seed_1 != seed_1 && this->desync_frame_seed == 0) this->desync_frame_seed = frame;
-		if (record.state_checksum != state_checksum && this->desync_frame_state_checksum == 0) this->desync_frame_state_checksum = frame;
-
-		frame++;
-		server_idx = (server_idx + 1) % _network_server_sync_records->size();
 	}
 
 	return NETWORK_RECV_STATUS_OKAY;

src/network/network_server.h

@@ -89,9 +89,7 @@ public:
 	NetworkAddress client_address; ///< IP-address of the client (so they can be banned)
 
 	std::string desync_log;
-
-	uint desync_frame_seed = 0;
-	uint desync_frame_state_checksum = 0;
+	std::string desync_frame_info;
 
 	uint rcon_auth_failures = 0;
 	uint settings_auth_failures = 0;

src/network/network_sync.h

@@ -0,0 +1,61 @@
+/*
+ * This file is part of OpenTTD.
+ * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
+ * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/** @file network_sync.h Variables and function used for network sync tracking. */
+
+#ifndef NETWORK_SYNC_H
+#define NETWORK_SYNC_H
+
+#include "../core/ring_buffer.hpp"
+
+/* Sync debugging */
+struct NetworkSyncRecord {
+	uint32 frame;
+	uint32 seed_1;
+	uint64 state_checksum;
+};
+extern ring_buffer<NetworkSyncRecord> _network_sync_records;
+extern ring_buffer<uint> _network_sync_record_counts;
+extern bool _record_sync_records;
+
+enum NetworkSyncRecordEvents : uint32 {
+	NSRE_BEGIN,
+	NSRE_CMD,
+	NSRE_AUX_TILE,
+	NSRE_TILE,
+	NSRE_TOWN,
+	NSRE_TREE,
+	NSRE_STATION,
+	NSRE_INDUSTRY,
+	NSRE_PRE_COMPANY_STATE,
+	NSRE_VEH_PERIODIC,
+	NSRE_VEH_LOAD_UNLOAD,
+	NSRE_VEH_EFFECT,
+	NSRE_VEH_TRAIN,
+	NSRE_VEH_ROAD,
+	NSRE_VEH_AIR,
+	NSRE_VEH_SHIP,
+	NSRE_VEH_OTHER,
+	NSRE_VEH_SELL,
+	NSRE_VEH_TBTR,
+	NSRE_VEH_AUTOREPLACE,
+	NSRE_VEH_REPAIR,
+	NSRE_FRAME_DONE,
+	NSRE_LAST,
+};
+
+void RecordSyncEventData(NetworkSyncRecordEvents event);
+const char *GetSyncRecordEventName(NetworkSyncRecordEvents event);
+
+inline void RecordSyncEvent(NetworkSyncRecordEvents event)
+{
+	if (_record_sync_records) {
+		RecordSyncEventData(event);
+	}
+}
+
+#endif /* NETWORK_SYNC_H */

src/openttd.cpp

@@ -91,6 +91,7 @@
 #include "network/network_survey.h"
 #include "timer/timer.h"
 #include "timer/timer_game_tick.h"
+#include "network/network_sync.h"
 
 #include "linkgraph/linkgraphschedule.h"
 #include "tracerestrict.h"
@@ -2133,6 +2134,7 @@ void StateGameLoop()
 		NewsLoop();
 
 		if (_networking) {
+			RecordSyncEvent(NSRE_PRE_COMPANY_STATE);
 			for (Company *c : Company::Iterate()) {
 				DEBUG_UPDATESTATECHECKSUM("Company: %u, Money: " OTTD_PRINTF64, c->index, (int64)c->money);
 				UpdateStateChecksum(c->money);

src/vehicle.cpp

@@ -60,6 +60,7 @@
 #include "string_func.h"
 #include "scope_info.h"
 #include "debug_settings.h"
+#include "network/network_sync.h"
 #include "3rdparty/cpp-btree/btree_set.h"
 #include "3rdparty/cpp-btree/btree_map.h"
 
@@ -1498,6 +1499,8 @@ void CallVehicleTicks()
 		}
 	}
 
+	RecordSyncEvent(NSRE_VEH_PERIODIC);
+
 	{
 		PerformanceMeasurer framerate(PFE_GL_ECONOMY);
 		Station *si_st = nullptr;
@@ -1508,6 +1511,8 @@ void CallVehicleTicks()
 		}
 	}
 
+	RecordSyncEvent(NSRE_VEH_LOAD_UNLOAD);
+
 	if (!_tick_caches_valid || HasChickenBit(DCBF_VEH_TICK_CACHE)) RebuildVehicleTickCaches();
 
 	Vehicle *v = nullptr;
@@ -1523,9 +1528,10 @@ void CallVehicleTicks()
 			u->EffectVehicle::Tick();
 		}
 	}
+	if (!_tick_effect_veh_cache.empty()) RecordSyncEvent(NSRE_VEH_EFFECT);
 	{
 		PerformanceMeasurer framerate(PFE_GL_TRAINS);
-		for (Train *t :  _tick_train_too_heavy_cache) {
+		for (Train *t : _tick_train_too_heavy_cache) {
 			if (HasBit(t->flags, VRF_TOO_HEAVY)) {
 				if (t->owner == _local_company) {
 					SetDParam(0, t->index);
@@ -1546,6 +1552,7 @@ void CallVehicleTicks()
 			}
 		}
 	}
+	RecordSyncEvent(NSRE_VEH_TRAIN);
 	{
 		PerformanceMeasurer framerate(PFE_GL_ROADVEHS);
 		for (RoadVehicle *front : _tick_road_veh_front_cache) {
@@ -1558,6 +1565,7 @@ void CallVehicleTicks()
 			if (!(front->vehstatus & VS_STOPPED)) VehicleTickMotion(front, front);
 		}
 	}
+	if (!_tick_road_veh_front_cache.empty()) RecordSyncEvent(NSRE_VEH_ROAD);
 	{
 		PerformanceMeasurer framerate(PFE_GL_AIRCRAFT);
 		for (Aircraft *front : _tick_aircraft_front_cache) {
@@ -1569,6 +1577,7 @@ void CallVehicleTicks()
 			if (!(front->vehstatus & VS_STOPPED)) VehicleTickMotion(front, front);
 		}
 	}
+	if (!_tick_aircraft_front_cache.empty()) RecordSyncEvent(NSRE_VEH_AIR);
 	{
 		PerformanceMeasurer framerate(PFE_GL_SHIPS);
 		for (Ship *s : _tick_ship_cache) {
@@ -1580,6 +1589,7 @@ void CallVehicleTicks()
 			if (!(s->vehstatus & VS_STOPPED)) VehicleTickMotion(s, s);
 		}
 	}
+	if (!_tick_ship_cache.empty()) RecordSyncEvent(NSRE_VEH_SHIP);
 	{
 		for (Vehicle *u : _tick_other_veh_cache) {
 			if (!u) continue;
@@ -1588,6 +1598,7 @@ void CallVehicleTicks()
 		}
 	}
 	v = nullptr;
+	if (!_tick_other_veh_cache.empty()) RecordSyncEvent(NSRE_VEH_OTHER);
 
 	/* Handle vehicles marked for immediate sale */
 	Backup<CompanyID> sell_cur_company(_current_company, FILE_LINE);
@@ -1616,6 +1627,7 @@ void CallVehicleTicks()
 		_vehicles_to_autoreplace.erase(index);
 	}
 	sell_cur_company.Restore();
+	if (!_vehicles_to_sell.empty()) RecordSyncEvent(NSRE_VEH_SELL);
 
 	/* do Template Replacement */
 	Backup<CompanyID> tmpl_cur_company(_current_company, FILE_LINE);
@@ -1664,6 +1676,7 @@ void CallVehicleTicks()
 		}
 	}
 	tmpl_cur_company.Restore();
+	if (!_vehicles_to_templatereplace.empty()) RecordSyncEvent(NSRE_VEH_TBTR);
 
 	/* do Auto Replacement */
 	Backup<CompanyID> cur_company(_current_company, FILE_LINE);
@@ -1701,6 +1714,7 @@ void CallVehicleTicks()
 		ShowAutoReplaceAdviceMessage(res, v);
 	}
 	cur_company.Restore();
+	if (!_vehicles_to_autoreplace.empty()) RecordSyncEvent(NSRE_VEH_AUTOREPLACE);
 
 	Backup<CompanyID> repair_cur_company(_current_company, FILE_LINE);
 	for (VehicleID index : _vehicles_to_pay_repair) {
@@ -1743,6 +1757,7 @@ void CallVehicleTicks()
 		v->breakdowns_since_last_service = 0;
 	}
 	repair_cur_company.Restore();
+	if (!_vehicles_to_pay_repair.empty()) RecordSyncEvent(NSRE_VEH_REPAIR);
 	_vehicles_to_pay_repair.clear();
 }