C# 从不同的线程读取和写入相同的内存
我有一个简单的类,它异步发送请求C# 从不同的线程读取和写入相同的内存,c#,.net,multithreading,async-await,thread-synchronization,C#,.net,Multithreading,Async Await,Thread Synchronization,我有一个简单的类,它异步发送请求 public class MyClass { private readonly ISender _sender; public MyClass(ISender sender) { _sender = sender; } public Task<string> SendAsync(string input, CancellationToken cancellationToken) {
public class MyClass
{
private readonly ISender _sender;
public MyClass(ISender sender)
{
_sender = sender;
}
public Task<string> SendAsync(string input, CancellationToken cancellationToken)
{
return _sender.SendAsync(input, cancellationToken);
}
}
public interface ISender
{
Task<string> SendAsync(string input, CancellationToken cancellationToken);
}
公共类MyClass
{
专用只读ISender\u发送方;
公共MyClass(ISender发件人)
{
_发送方=发送方;
}
公共任务SendAsync(字符串输入,CancellationToken CancellationToken)
{
返回_sender.SendAsync(输入,取消令牌);
}
}
公共接口ISender
{
任务SendAsync(字符串输入,CancellationToken CancellationToken);
}
所有这些看起来都很简单,直到满足以下要求:\可以在运行时更改发送方
MyClass的新实现:
public class MyClass
{
private readonly ISender _sender;
public MyClass(ISender sender)
{
_sender = sender;
}
public Task<string> SendAsync(string input, CancellationToken cancellationToken)
{
return _sender.SendAsync(input, cancellationToken);
}
public void SenderChanged(object unused, SenderEventArgs e)
{
ISender previous = Interlocked.Exchange(ref _sender, SenderFactory.Create(e.NewSenderConfig));
previous.Dispose();
}
}
公共类MyClass
{
专用只读ISender\u发送方;
公共MyClass(ISender发件人)
{
_发送方=发送方;
}
公共任务SendAsync(字符串输入,CancellationToken CancellationToken)
{
返回_sender.SendAsync(输入,取消令牌);
}
已更改公用无效发件人(未使用的对象,发件人目标)
{
ISender previous=Interlocked.Exchange(参考发送方,发送方工厂创建(例如NewSenderConfig));
previous.Dispose();
}
}
显然,这段代码不是线程安全的。我需要在sendsync
和SenderChanged
中引入lock
,以确保发送方始终是最新的对象。
但是我希望SenderChanged
每天调用一次,并且sendsync
(读取\u sender对象)每秒调用10000次。锁定
和上下文切换会破坏此代码的性能
是否有可能通过低电平锁定来处理此问题?或者,在了解上述要求的情况下,您将如何解决此问题 通常的方法是使用读写器锁,特别是。这是一个类似监视器的锁,可以优化频繁读访问和不频繁写访问,并且它支持多个并发读卡器和一个写卡器,这似乎正是您的用例 然而,它的成本似乎并不高。我编写了两个测试—一个使用
readerwriterlocksim
正确地执行操作,另一个使用您的实现,唯一的更改是一个已处理的异常重试循环。就我而言,我更换了20次发件人,每10秒一次。这比您提议的用例要短得多,但可以作为性能差异的估计
最后:
- 读写器锁每毫秒能通过2878个工作单位
- “带重试功能的裸机”能够以每秒9940个工作单位的速度运行
Thread.SpinWait(100)
。如果您想自己测试,下面将发布代码
编辑:
我调整了Thread.SpinWait()
调用,以更改在锁定和“工作”上花费的时间的平衡。在我的机器上,旋转等待大约为900-1000次,两种实现以相同的速度运行,大约1000个工作单位/毫秒。从上面的结果来看,这应该是显而易见的,但我确实想做一次理智检查
事实上,最初的结果表明,我们能够使用锁每秒处理大约280万个请求;至少在我的4核Intel CPU机器上,“Intel core 2 Quad CPU Q9650@3.00 GHz”。考虑到您正在争取每秒10k请求,在锁定开始成为CPU使用的重要部分之前,您似乎已经有了大约一个数量级的净空
#定义使用读写器
使用制度;
使用System.Collections.Generic;
使用系统诊断;
使用System.Linq;
使用系统线程;
使用System.Threading.Tasks;
使用System.Windows.Forms;
命名空间测试项目
{
静态类程序
{
///
///应用程序的主要入口点。
///
[状态线程]
静态void Main()
{
SenderDispatch dispatch=新SenderDispatch();
列表工作者=新列表();
工人。添加(新工人(派遣,“A”);
工人。添加(新工人(派遣,“B”);
增加(新工人(派遣,“C”);
工人。增加(新工人(派遣,“D”);
Thread.CurrentThread.Name=“主线程”;
Process.GetCurrentProcess().PriorityClass=ProcessPriorityClass.High;
秒表=新秒表();
watch.Start();
ForEach(x=>x.Start());
对于(int i=0;i<20;i++)
{
睡眠(10000);
dispatch.NewSender();
}
控制台。写入线(“停止…”);
ForEach(x=>x.Stop());
看,停;
控制台。写入线(“停止”);
long sum=workers.sum(x=>x.FinalCount);
字符串消息=
工作循环次数之和:“+Sum.ToString(“n0”)+”\r\n+
“总时间:”+(watch.elapsedmillyses/1000.0)。ToString(“0.000”)+“\r\n”+
“迭代次数/ms:+sum/watch.elapsedmillyses;
MessageBox.Show(message);
}
}
公社工人
{
专用发送器调度调度器;
私有线程;
私人布尔工作;
私有字符串工作名;
公共工作人员(发送方Dispatch dispatcher、字符串工作名)
{
this.dispatcher=dispatcher;
this.workerName=workerName;
这个工作=假;
}
公共长FinalCount{get;private set;}
公开作废开始()
{
this.thread=新线程(运行);
this.thread.Name=“Worker”+this.workerName;
这是真的;
this.thread.Start();
}
脉波重复间隔
#define USE_READERWRITER
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using System.Windows.Forms;
namespace TestProject
{
static class Program
{
/// <summary>
/// The main entry point for the application.
/// </summary>
[STAThread]
static void Main()
{
SenderDispatch dispatch = new SenderDispatch();
List<Worker> workers = new List<Worker>();
workers.Add( new Worker( dispatch, "A" ) );
workers.Add( new Worker( dispatch, "B" ) );
workers.Add( new Worker( dispatch, "C" ) );
workers.Add( new Worker( dispatch, "D" ) );
Thread.CurrentThread.Name = "Main thread";
Process.GetCurrentProcess().PriorityClass = ProcessPriorityClass.High;
Stopwatch watch = new Stopwatch();
watch.Start();
workers.ForEach( x => x.Start() );
for( int i = 0; i < 20; i++ )
{
Thread.Sleep( 10000 );
dispatch.NewSender();
}
Console.WriteLine( "Stopping..." );
workers.ForEach( x => x.Stop() );
watch.Stop();
Console.WriteLine( "Stopped" );
long sum = workers.Sum( x => x.FinalCount );
string message =
"Sum of worker iterations: " + sum.ToString( "n0" ) + "\r\n" +
"Total time: " + ( watch.ElapsedMilliseconds / 1000.0 ).ToString( "0.000" ) + "\r\n" +
"Iterations/ms: " + sum / watch.ElapsedMilliseconds;
MessageBox.Show( message );
}
}
public class Worker
{
private SenderDispatch dispatcher;
private Thread thread;
private bool working;
private string workerName;
public Worker( SenderDispatch dispatcher, string workerName )
{
this.dispatcher = dispatcher;
this.workerName = workerName;
this.working = false;
}
public long FinalCount { get; private set; }
public void Start()
{
this.thread = new Thread( Run );
this.thread.Name = "Worker " + this.workerName;
this.working = true;
this.thread.Start();
}
private void Run()
{
long state = 0;
while( this.working )
{
this.dispatcher.DoOperation( workerName, state );
state++;
}
this.FinalCount = state;
}
public void Stop()
{
this.working = false;
this.thread.Join();
}
}
public class SenderDispatch
{
private Sender sender;
private ReaderWriterLockSlim senderLock;
public SenderDispatch()
{
this.sender = new Sender();
this.senderLock = new ReaderWriterLockSlim( LockRecursionPolicy.NoRecursion );
}
public void DoOperation( string workerName, long value )
{
#if USE_READERWRITER
this.senderLock.EnterReadLock();
try
{
this.sender.DoOperation( workerName, value );
}
finally
{
this.senderLock.ExitReadLock();
}
#else
bool done = false;
do
{
try
{
this.sender.DoOperation( workerName, value );
done = true;
}
catch (ObjectDisposedException) { }
}
while( !done );
#endif
}
public void NewSender()
{
Sender prevSender;
Sender newSender;
newSender = new Sender();
#if USE_READERWRITER
this.senderLock.EnterWriteLock();
try
{
prevSender = Interlocked.Exchange( ref this.sender, newSender );
}
finally
{
this.senderLock.ExitWriteLock();
}
#else
prevSender = Interlocked.Exchange( ref this.sender, newSender );
prevSender.Dispose();
#endif
prevSender.Dispose();
}
}
public class Sender : IDisposable
{
private bool disposed;
public Sender()
{
this.disposed = false;
}
public void DoOperation( string workerName, long value )
{
if( this.disposed )
{
throw new ObjectDisposedException(
"Sender",
string.Format( "Worker {0} tried to queue work item {1}", workerName, value )
);
}
Thread.SpinWait( 100 );
}
public void Dispose()
{
this.disposed = true;
}
}
}