perf(server): hold 20 TPS at 50-player scale

Minecraft.Server/ServerLogger.cpp

@@ -15,6 +15,8 @@ static volatile LONG g_minLogLevel = (LONG)eServerLogLevel_Info;
 static FILE *g_logFile = NULL;
 static std::once_flag g_logFileOnce;
 
+bool g_serverPerfTrace = false;
+
 static void OpenLogFile()
 {
 	if (g_logFile != NULL)

Minecraft.Server/ServerLogger.h

@@ -41,4 +41,9 @@ namespace ServerRuntime
 	void LogStartupStep(const char *message);
 	void LogWorldIO(const char *message);
 	void LogWorldName(const char *prefix, const std::wstring &name);
+
+	// When true, noisy [perf] sampling output (histograms, per-iter samples)
+	// is enabled. Threshold-fired warnings remain always-on. Toggled via the
+	// -perftrace CLI flag.
+	extern bool g_serverPerfTrace;
 }

Minecraft.Server/Windows64/ServerMain.cpp

@@ -166,6 +166,7 @@ static void PrintUsage()
 	ServerRuntime::LogInfo("usage", "  -maxplayers <1-8>     Public slots (default: server.properties:max-players)");
 	ServerRuntime::LogInfo("usage", "  -seed <int64>         World seed (overrides server.properties:level-seed)");
 	ServerRuntime::LogInfo("usage", "  -loglevel <level>     debug|info|warn|error (default: server.properties:log-level)");
+	ServerRuntime::LogInfo("usage", "  -perftrace            Enable noisy [perf] sampling output (histograms, per-iter samples)");
 	ServerRuntime::LogInfo("usage", "  -help                 Show this help");
 }
 
@@ -272,6 +273,10 @@ static bool ParseCommandLine(int argc, char **argv, DedicatedServerConfig *confi
 				return false;
 			}
 		}
+		else if (_stricmp(arg, "-perftrace") == 0)
+		{
+			ServerRuntime::g_serverPerfTrace = true;
+		}
 		else
 		{
 			LogErrorf("startup", "Unknown or incomplete argument: %s", arg);