ManualResetEventSlim performance improvements

diff --git a/mcs/class/corlib/System.Threading/ManualResetEventSlim.cs b/mcs/class/corlib/System.Threading/ManualResetEventSlim.cs
index 5cf5ae312ce3571f7e9e7c93521f70bf5e4bea42..472975ef77d9216b78bfac80c66b96aa52f31f49 100644 (file)
--- a/mcs/class/corlib/System.Threading/ManualResetEventSlim.cs
+++ b/mcs/class/corlib/System.Threading/ManualResetEventSlim.cs
@@ -25,7 +25,6 @@
 #if NET_4_0 || BOOTSTRAP_NET_4_0
 
 using System;
-using System.Diagnostics;
 
 namespace System.Threading
 {
@@ -40,6 +39,8 @@ namespace System.Threading
 
                ManualResetEvent handle;
 
+               readonly static Watch sw = Watch.StartNew ();
+
                public ManualResetEventSlim () : this (false, defaultSpinCount)
                {
                }
@@ -72,6 +73,7 @@ namespace System.Threading
                public void Reset ()
                {
                        Interlocked.Exchange (ref state, isNotSet);
+                       //state = isNotSet;
                        if (handle != null)
                                handle.Reset ();
                }
@@ -79,6 +81,7 @@ namespace System.Threading
                public void Set ()
                {
                        Interlocked.Exchange (ref state, isSet);
+                       //state = isSet;
                        if (handle != null)
                                handle.Set ();
                }
@@ -109,19 +112,19 @@ namespace System.Threading
                                throw new ArgumentOutOfRangeException ("millisecondsTimeout",
                                                                       "millisecondsTimeout is a negative number other than -1");
 
-                       Watch s = Watch.StartNew ();
-                       SpinWait sw = new SpinWait ();
+                       long start = ms == -1 ? 0 : sw.ElapsedMilliseconds;
+                       SpinWait wait = new SpinWait ();
 
                        while (state == isNotSet) {
                                token.ThrowIfCancellationRequested ();
 
-                               if (ms > -1 && s.ElapsedMilliseconds > ms)
+                               if (ms > -1 && (sw.ElapsedMilliseconds - start) > ms)
                                        return false;
 
-                               if (sw.Count < spinCount) {
-                                       sw.SpinOnce ();
+                               if (wait.Count < spinCount) {
+                                       wait.SpinOnce ();
                                } else {
-                                       int waitTime = ms == -1 ? -1 : Math.Max (ms - (int)s.ElapsedMilliseconds, 1);
+                                       int waitTime = ms == -1 ? -1 : Math.Max (ms - (int)(sw.ElapsedMilliseconds - start) , 1);
                                        WaitHandle handle = WaitHandle;
                                        if (state == isSet)
                                                return true;