[英]Thread synchronizing using Tasks and Parallel APIs
我粘贴了4个代码段,其中尝试使用以下API进行并行化:
Parallel.ForEach
Parallel.Invoke
Task.Run
Task.Factory.StartNew
问题尝试并行化,以使有两个for循环,内部循环和外部循环,并且每次执行外部循环时,内部循环中的所有内容都应在并行中执行。
我可以使用Parallel.ForEach
使其工作,其他所有原因都会导致内部计数器异常,该值超出了数组索引,而我认为情况并非如此。 索引也会比目标高一个值,例如,当索引的大小为500时,它会尝试访问值500,理想情况下它应该在499处停止。我是否错过了什么。 以下是代码段,请看一下:
并行ForEach(工作)
using System;
using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;
namespace TestThreads
{
class Elements
{
public int innerValue;
public int outerValue;
public Elements(int innerValue, int outerValue)
{
this.innerValue = innerValue;
this.outerValue = outerValue;
}
}
class Program
{
private static int threadingCounter = 0;
private static int innerCounter = 500;
private static int outerCounter = 1000;
private static int[,] inOut;
private static int hitCount = 0;
private static int exceptionCount = 0;
private static List<int> innerCount = new List<int>();
static void Main(string[] args)
{
inOut = new int[innerCounter, outerCounter];
Program myProgram = new Program();
for (int iCount = 0; iCount < innerCounter; iCount++)
innerCount.Add(iCount);
try
{
for (int outer = 0; outer < outerCounter; outer++)
{
Parallel.ForEach<int>(innerCount, inner =>
{
myProgram.ThreadCall(new Elements(inner,outer));
}
);
Console.WriteLine("Main Thread Released Post Wait ...");
Console.WriteLine("Hit Count :: " + hitCount);
Console.WriteLine("Exception Count :: " + exceptionCount);
if (threadingCounter != 0)
Console.WriteLine("Threading Counter post Inner Loop :: " + threadingCounter);
}
}
catch (Exception ex)
{
Console.WriteLine("Exception :: " + ex.Message);
}
finally
{
if (innerCount != null)
innerCount = null;
}
}
public void ThreadCall(object state)
{
try
{
Interlocked.Increment(ref hitCount);
Elements localElement = (Elements)state;
int localInner = localElement.innerValue;
int localOuter = localElement.outerValue;
int finalValue = inOut[localInner, localOuter];
}
catch (Exception ex)
{
Console.WriteLine("Exception :: " + ex.Message);
}
}
}
}
Parallel.Invoke(由于索引值超出数组而失败,尝试获取内部索引-500)
using System;
using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;
namespace TestThreads
{
/// <summary>
///
/// </summary>
class Elements
{
public int innerValue;
public int outerValue;
public Elements(int innerValue, int outerValue)
{
this.innerValue = innerValue;
this.outerValue = outerValue;
}
}
/// <summary>
///
/// </summary>
class Program
{
private static int innerCounter = 500;
private static int outerCounter = 1000;
private static int[,] inOut;
private static int hitCount = 0;
private static int exceptionCount = 0;
private static List<Action> alSync = new List<Action>();
/// <summary>
///
/// </summary>
/// <param name="args"></param>
static void Main(string[] args)
{
inOut = new int[innerCounter, outerCounter];
Program myProgram = new Program();
try
{
for (int outer = 0; outer < outerCounter; outer++)
{
for (int inner = 0; inner < innerCounter; inner++)
alSync.Add(() => myProgram.ThreadCall(new Elements(inner, outer)));
Parallel.Invoke(alSync.ToArray());
alSync.Clear();
Console.WriteLine("Main Thread Released Post Wait ...");
Console.WriteLine("Hit Count :: " + hitCount);
Console.WriteLine("Exception Count :: " + exceptionCount);
}
}
catch (Exception ex)
{
Console.WriteLine("Exception :: " + ex.Message);
}
finally
{
if (alSync != null)
alSync = null;
}
}
/// <summary>
///
/// </summary>
/// <param name="state"></param>
public void ThreadCall(object state)
{
try
{
Interlocked.Increment(ref hitCount);
Elements localElement = (Elements)state;
int localInner = localElement.innerValue;
int localOuter = localElement.outerValue;
int finalValue = inOut[localInner, localOuter];
}
catch (Exception ex)
{
Interlocked.Increment(ref exceptionCount);
Console.WriteLine("Exception :: " + ex.Message);
}
}
}
}
Task.Run(由于索引值超出数组而失败,尝试获取内部索引-500)
using System;
using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;
namespace TestThreads
{
/// <summary>
///
/// </summary>
class Elements
{
public int innerValue;
public int outerValue;
public Elements(int innerValue, int outerValue)
{
this.innerValue = innerValue;
this.outerValue = outerValue;
}
}
/// <summary>
///
/// </summary>
class Program
{
private static int innerCounter = 500;
private static int outerCounter = 1000;
private static int[,] inOut;
private static int hitCount = 0;
private static int exceptionCount = 0;
private static List<Task> tlSync = new List<Task>();
/// <summary>
///
/// </summary>
/// <param name="args"></param>
static void Main(string[] args)
{
inOut = new int[innerCounter, outerCounter];
Program myProgram = new Program();
try
{
for (int outer = 0; outer < outerCounter; outer++)
{
for (int inner = 0; inner < innerCounter; inner++)
tlSync.Add(Task.Run(() => myProgram.ThreadCall(new Elements(inner, outer))));
Task.WaitAll(tlSync.ToArray());
tlSync.Clear();
Console.WriteLine("Main Thread Released Post Wait ...");
Console.WriteLine("Hit Count :: " + hitCount);
Console.WriteLine("Exception Count :: " + exceptionCount);
}
}
catch (Exception ex)
{
Console.WriteLine("Exception :: " + ex.Message);
}
finally
{
if (tlSync != null)
tlSync = null;
}
}
/// <summary>
///
/// </summary>
/// <param name="state"></param>
public void ThreadCall(object state)
{
try
{
Interlocked.Increment(ref hitCount);
Elements localElement = (Elements)state;
int localInner = localElement.innerValue;
int localOuter = localElement.outerValue;
int finalValue = inOut[localInner, localOuter];
}
catch (Exception ex)
{
Interlocked.Increment(ref exceptionCount);
Console.WriteLine("Exception :: " + ex.Message);
}
}
}
}
Task.Factory.StartNew(由于索引值超出数组而失败,尝试获取内部索引-500)
using System;
using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;
namespace TestThreads
{
/// <summary>
///
/// </summary>
class Elements
{
public int innerValue;
public int outerValue;
public Elements(int innerValue, int outerValue)
{
this.innerValue = innerValue;
this.outerValue = outerValue;
}
}
/// <summary>
///
/// </summary>
class Program
{
private static int innerCounter = 500;
private static int outerCounter = 1000;
private static int[,] inOut;
private static int hitCount = 0;
private static int exceptionCount = 0;
private static List<Task> tlSync = new List<Task>();
/// <summary>
///
/// </summary>
/// <param name="args"></param>
static void Main(string[] args)
{
inOut = new int[innerCounter, outerCounter];
Program myProgram = new Program();
try
{
for (int outer = 0; outer < outerCounter; outer++)
{
for (int inner = 0; inner < innerCounter; inner++)
tlSync.Add(Task.Factory.StartNew(() =>
myProgram.ThreadCall(new Elements(inner, outer))));
Task.WaitAll(tlSync.ToArray());
tlSync.Clear();
Console.WriteLine("Main Thread Released Post Wait ...");
Console.WriteLine("Hit Count :: " + hitCount);
Console.WriteLine("Exception Count :: " + exceptionCount);
}
}
catch (Exception ex)
{
Console.WriteLine("Exception :: " + ex.Message);
}
finally
{
if (tlSync != null)
tlSync = null;
}
}
/// <summary>
///
/// </summary>
/// <param name="state"></param>
public void ThreadCall(object state)
{
try
{
Interlocked.Increment(ref hitCount);
Elements localElement = (Elements)state;
int localInner = localElement.innerValue;
int localOuter = localElement.outerValue;
int finalValue = inOut[localInner, localOuter];
}
catch (Exception ex)
{
Interlocked.Increment(ref exceptionCount);
Console.WriteLine("Exception :: " + ex.Message);
}
}
}
}
不知道tlSync的用途是什么,我看不到为什么要将任务推送到通用列表。
如果您想做一些事情并更新用户界面,则可以从我曾经写过的表单程序中使用的这个功能中得到启发
var ui = TaskScheduler.FromCurrentSynchronizationContext();
someList
.ForEach(f => Task.Factory.StartNew(() =>
{
// do stuff
})
.ContinueWith(task =>
{
if (task.IsCompleted)
{
// update UI
// called after each task above completes
}
}, ui));
或者您可能对内部/外部有关闭问题,可以尝试更改此代码
for (int inner = 0; inner < innerCounter; inner++)
tlSync.Add(Task.Factory.StartNew(() => myProgram.ThreadCall(new Elements(inner, outer))));
对此
for (int inner = 0; inner < innerCounter; inner++) {
var nInner = inner;
var nOuter = outer;
tlSync.Add(Task.Factory.StartNew(() => myProgram.ThreadCall(new Elements(nInner, nOuter))));
}
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.