2006-11-22 Miguel de Icaza <miguel@novell.com>

	* DateTime.cs: A small performance hit, we store the actual time
	span in a boxed object.   This way, it can be updated from other
	threads if necessary.   We always unbox to get the value before
	any potential updates. 

	Thanks to Gonzalo for catching this.


svn path=/trunk/mcs/; revision=68379

1 files changed, 5 insertions, 3 deletions

diff --git a/mcs/class/corlib/System/DateTime.cs b/mcs/class/corlib/System/DateTime.cs
index 6b55b58c687..3579ce88386 100644
--- a/mcs/class/corlib/System/DateTime.cs
+++ b/mcs/class/corlib/System/DateTime.cs
@@ -423,7 +423,7 @@ namespace System
 		// time into `to_local_time_span', we record the timestamp
 		// for this in `last_now'
 		//
-		static TimeSpan to_local_time_span;
+		static object to_local_time_span_object;
 		static long last_now;
 		
 		public static DateTime Now 
@@ -434,11 +434,13 @@ namespace System
 				DateTime dt = new DateTime (now);
 				
 				if ((now - last_now) > TimeSpan.TicksPerMinute){
-					to_local_time_span = TimeZone.CurrentTimeZone.GetLocalTimeDiff (dt);
+					to_local_time_span_object = TimeZone.CurrentTimeZone.GetLocalTimeDiff (dt);
 					last_now = now;
 
 				}
-				return dt + to_local_time_span;
+
+				// This is boxed, so we avoid locking.
+				return dt + (TimeSpan) to_local_time_span_object;
 			}
 		}