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PLINQ Powered by TPL in .Net 4.0 C#

By Amit Choudhary on August 04, 2011
My previous post discussed the TPL library and its uses to create the scalable applications. Another way to incorporate the parallel task into your .Net applications is through PLINQ.
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My previous post discussed the TPL library and its uses to create the scalable applications. Another way to incorporate the parallel task into your .Net applications is through PLINQ.

LINQ queries which are designed to run in Parallel are termed as PLINQ queries.

The framework of PLINQ has been optimized in such a way that it includes determining if a query can perform faster in a synchronous manner. Is analyze the LINQ query at run time if its likely to benefit from parallelization, when run concurrently.

The TPL library provides the following methods to support the parallel LINQ queries.

AsParallel()

Specifies that the rest of the query should be parallelized, if possible.

WithCancellation()

Specifies that PLINQ should periodically check for the state of the provided CancellationToken and cancel execution if it is required.

WithDegreeOfParallelism()

Specifies the maximum number of processors that PLINQ should use to parallelize the query.

ForAll()

Enables results to be processed in parallel without first merging back to the consumer thread, as would be the case when enumerating a LINQ result using the foreach keyword.

Let's see the demo:

Creating the first PLINQ query:

If you want to use TPL to execute your query in parallel (if possible), then you will want to use the AsParallel() extension method:

//Prepare the query
int[] modeThreeIsZero = (from num in source.AsParallel()
                         where (num % 3) == 0
                         orderby num descending
                         select num).ToArray();

Here is the complete code:

namespace PLINQ_Demo
{
    class Program
    {
        static DateTime startTime;
        static void Main(string[] args)
        {
            ProcessIntDataNormalMode();
            ProcessIntDataNormalMode();
            Console.ReadLine();
        }

        private static void ProcessIntDataNormalMode()
        {
            //record current time
            startTime = DateTime.Now;
 
            //Get a random large array of integers
            int[] source = Enumerable.Range(1, 10000000).ToArray();

            //Prepare the query
            int[] modeThreeIsZero = (from num in source.AsParallel()
                                     where (num % 3) == 0
                                     orderby num descending
                                     select num).ToArray();
            //timer
            TimeSpan ts = DateTime.Now.Subtract(startTime);

            //Process and show the result
            Console.WriteLine("{0} numbers found as result. \n Time Elapsed: {1} Seconds:MilliSeconds in Normal mode", modeThreeIsZero.Count(), ts.Seconds + ":" + ts.Milliseconds);
        }

        private static void ProcessIntDataParallelMode()
        {
            //record current time
            startTime = DateTime.Now;

            //Get a random large array of integers
            int[] source = Enumerable.Range(1, 10000000).ToArray();

            //Prepare the query
            int[] modeThreeIsZero = (from num in source.AsParallel()
                                     where (num % 3) == 0
                                     orderby num descending
                                     select num).ToArray();

            //timer
            TimeSpan ts = DateTime.Now.Subtract(startTime);
            //Process and show the result
            Console.WriteLine("{0} numbers found as result \n Time Elapsed: {1} [Seconds:MilliSeconds] in parallel mode.", modeThreeIsZero.Count(), ts.Seconds + ":" + ts.Milliseconds);
        }
    }
}

Output:

TPL

Amit Choudhary

Amit is a software developer by profession and blogger by choice. He's Practicing in C#, .Net framework, ASP.NET, Silverlight, Windows Phone, ADO.NET, Linq,  Xml, Web Services, JQuery, and Sql server. Amit is MindC... Read more

Personal Blog: http://www.cshandler.com
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