Synchronize Threads

Question

I have a 3-thread application, this application involves a chemical process simulator, and I have to take some values of these processes. values come in a single object.

The 3 threads make an infinite loop, in this loop they take the values at different times, which cannot happen.

I wanted to know if there’s any way I can synchronize the threads, so when they go to pick up the object all 3 pick up at the same time.

Here are my threads:

public void RunController()
{
     Softing.OPCToolbox.Client.Application app = Softing.OpcToolbox.Client.Application.Instance;
     app.Initialize();
     while(true)
     {
          scase.Solver.Integrator.IsRunning = true;
          Thread.Sleep(1000);
          scase.Solver.Integrator.IsRunning = false;
          scase = Interaction.GetObject(opcform.pasta);
          Contrl();
          GC.Collect();
     }
}




public void RunExport()
{
     Softing.OPCToolbox.Client.Application app = Softing.OpcToolbox.Client.Application.Instance;
     app.Initialize();
     while(true)
     {
          scase.Solver.Integrator.IsRunning = true;
          Thread.Sleep(1000);
          scase.Solver.Integrator.IsRunning = false;
          scase = Interaction.GetObject(opcform.pasta);
          Exprt();
          GC.Collect();
     }
}



public void RunImport()
{
     Softing.OPCToolbox.Client.Application app = Softing.OpcToolbox.Client.Application.Instance;
     app.Initialize();
     while(true)
     {
          scase.Solver.Integrator.IsRunning = true;
          Thread.Sleep(1000);
          scase.Solver.Integrator.IsRunning = false;
          scase = Interaction.GetObject(opcform.pasta);
          Imprt();
          GC.Collect();
     }
}

I’d like them to execute the scase = Interaction.GetObject(opcform.pasta); at the same time.

Answer 1

Given the problem you’re facing, I don’t think it’s interesting that you create Threads that way. You’d be dealing with unnecessary competition.

You have entries, jobs that need to be executed (maybe in parallel, maybe not), and waiting for outputs. This is a typical example of using Tasks in C#, which may or may not be executed in parallel.

This article is very interesting of how tasks can be used: http://msdn.microsoft.com/en-us/library/dd537609%28v=vs.110%29.aspx

Take this example:

using System;
using System.Threading.Tasks;

public class Example
{
   public static void Main()
   {
        Task<Double>[] taskArray = { Task<Double>.Factory.StartNew(() => DoComputation(1.0)),
                                     Task<Double>.Factory.StartNew(() => DoComputation(100.0)), 
                                     Task<Double>.Factory.StartNew(() => DoComputation(1000.0)) };

        var results = new Double[taskArray.Length];
        Double sum = 0;

        for (int i = 0; i < taskArray.Length; i++) {
            results[i] = taskArray[i].Result;
            Console.Write("{0:N1} {1}", results[i], 
                              i == taskArray.Length - 1 ? "= " : "+ ");
            sum += results[i];
        }
        Console.WriteLine("{0:N1}", sum);
   }

   private static Double DoComputation(Double start)
   {
      Double sum = 0;
      for (var value = start; value <= start + 10; value += .1)
         sum += value;

      return sum; 
   }
}

This example starts the calculation in 3 distinct tasks. When adding the value, using the result task.Result, If the task is not finished, it waits until the end of its execution without stopping the others. Note that a synchronization is not required. You pass the values, they produce a result.

You can literally make a loop for and do when iterations you want. With each iteration, he re-launches the 3 tasks in parallel and re-joins the result.