diff --git a/Tun/Diagnostics/SDLLogger.swift b/Tun/Diagnostics/SDLLogger.swift
index c003261..1060228 100644
--- a/Tun/Diagnostics/SDLLogger.swift
+++ b/Tun/Diagnostics/SDLLogger.swift
@@ -14,13 +14,11 @@ public class SDLLogger: @unchecked Sendable {
         case trace = "com.jihe.punchnet.trace"
     }
     
-    private static var loggers: [String: SDLLogger] {
-        var loggers: [String: SDLLogger] = [:]
-        for sub in Subsystem.allCases {
-            loggers[sub.rawValue] = .init(subsystem: sub)
-        }
-        return loggers
-    }
+    private static let debugLoggingEnabled = ProcessInfo.processInfo.environment["SDL_DEBUG_LOG"] != "0"
+    private static let traceLoggingEnabled = ProcessInfo.processInfo.environment["SDL_TRACE_LOG"] == "1"
+    private static let loggers: [Subsystem: SDLLogger] = {
+        Dictionary(uniqueKeysWithValues: Subsystem.allCases.map { ($0, SDLLogger(subsystem: $0)) })
+    }()
     
     private let log: Logger
     
@@ -32,9 +30,20 @@ public class SDLLogger: @unchecked Sendable {
         self.log.info("\(message, privacy: .public)")
     }
     
-    public static func log(_ message: String, for system: Subsystem = .debug) {
-        if let logger = loggers[system.rawValue] {
-            logger._log(message)
+    public static func log(_ message: @autoclosure () -> String, for system: Subsystem = .debug) {
+        guard self.isEnabled(system), let logger = loggers[system] else {
+            return
+        }
+
+        logger._log(message())
+    }
+
+    private static func isEnabled(_ system: Subsystem) -> Bool {
+        switch system {
+        case .debug:
+            return self.debugLoggingEnabled
+        case .trace:
+            return self.traceLoggingEnabled
         }
     }
 }