ReaderWriterLockSlim 什么时候比一个简单的锁更好？
我正在用这段代码对 ReaderWriterLock 做一个非常愚蠢的基准测试，其中阅读发生的频率是写作的4倍:
class Program
{
static void Main()
{
ISynchro[] test = { new Locked(), new RWLocked() };
Stopwatch sw = new Stopwatch();
foreach ( var isynchro in test )
{
sw.Reset();
sw.Start();
Thread w1 = new Thread( new ParameterizedThreadStart( WriteThread ) );
w1.Start( isynchro );
Thread w2 = new Thread( new ParameterizedThreadStart( WriteThread ) );
w2.Start( isynchro );
Thread r1 = new Thread( new ParameterizedThreadStart( ReadThread ) );
r1.Start( isynchro );
Thread r2 = new Thread( new ParameterizedThreadStart( ReadThread ) );
r2.Start( isynchro );
w1.Join();
w2.Join();
r1.Join();
r2.Join();
sw.Stop();
Console.WriteLine( isynchro.ToString() + ": " + sw.ElapsedMilliseconds.ToString() + "ms." );
}
Console.WriteLine( "End" );
Console.ReadKey( true );
}
static void ReadThread(Object o)
{
ISynchro synchro = (ISynchro)o;
for ( int i = 0; i < 500; i++ )
{
Int32? value = synchro.Get( i );
Thread.Sleep( 50 );
}
}
static void WriteThread( Object o )
{
ISynchro synchro = (ISynchro)o;
for ( int i = 0; i < 125; i++ )
{
synchro.Add( i );
Thread.Sleep( 200 );
}
}
}
interface ISynchro
{
void Add( Int32 value );
Int32? Get( Int32 index );
}
class Locked:List<Int32>, ISynchro
{
readonly Object locker = new object();
#region ISynchro Members
public new void Add( int value )
{
lock ( locker )
base.Add( value );
}
public int? Get( int index )
{
lock ( locker )
{
if ( this.Count <= index )
return null;
return this[ index ];
}
}
#endregion
public override string ToString()
{
return "Locked";
}
}
class RWLocked : List<Int32>, ISynchro
{
ReaderWriterLockSlim locker = new ReaderWriterLockSlim();
#region ISynchro Members
public new void Add( int value )
{
try
{
locker.EnterWriteLock();
base.Add( value );
}
finally
{
locker.ExitWriteLock();
}
}
public int? Get( int index )
{
try
{
locker.EnterReadLock();
if ( this.Count <= index )
return null;
return this[ index ];
}
finally
{
locker.ExitReadLock();
}
}
#endregion
public override string ToString()
{
return "RW Locked";
}
}
但我得到的结论是，两者的表现方式大致相同:
Locked: 25003ms.
RW Locked: 25002ms.
End
即使读操作的次数是写操作的20倍，性能仍然(几乎)相同。
我做错什么了吗？
问候你。
最佳答案