Choose : Parallel or not in .NET 4.0 beta 2; Part 1

This is a little sample to choose parallel or not. It is used LINQ to object.

Example of source code:

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DateTime start = DateTime.MinValue;
DateTime stop = DateTime.MinValue;
TimeSpan seleisih;
Console.WriteLine("Sequential");

IEnumerable<int> cobaAss = Enumerable.Range(0, 30000000);
var hh = from x in cobaAss
         where x % 3 == 0
         select Math.Sqrt(x);
start = DateTime.Now;
foreach (var item in hh)
{
    double x = item * 1.5;
}
stop = DateTime.Now;
seleisih = stop - start;

Console.WriteLine("Start : {0}", start);
Console.WriteLine("Stop : {0}", stop);
Console.WriteLine("Selisih (tick) : {0}", seleisih.Ticks);

// --

Console.WriteLine("Parallel");

cobaAss = Enumerable.Range(0, 30000000);
hh = from x in cobaAss.AsParallel()
     where x % 3 == 0
     select Math.Sqrt(x);
start = DateTime.Now;
//Parallel.ForEach<double>(hh, (item) => { });
foreach (var item in hh)
{
    double x = item * 1.5;
}
stop = DateTime.Now;
seleisih = stop - start;

Console.WriteLine("Start : {0}", start);
Console.WriteLine("Stop : {0}", stop);
Console.WriteLine("Selisih (tick) : {0}", seleisih.Ticks);

Console.WriteLine("Parallel Doit manually");

var cobaAss1 = Enumerable.Range(0, 10000000);
var cobaAss2 = Enumerable.Range(10000000, 10000000);
var cobaAss3 = Enumerable.Range(20000000, 10000000);

var hh1 = from x in cobaAss
          where x % 3 == 0
          select Math.Sqrt(x);
var hh2 = from x in cobaAss
          where x % 3 == 0
          select Math.Sqrt(x);
var hh3 = from x in cobaAss
          where x % 3 == 0
          select Math.Sqrt(x);
start = DateTime.Now;
Parallel.Invoke(
    () =>
    {
        foreach (var item in hh1)
        {
            double x = item * 1.5;
        }
    },
    () =>
    {
        foreach (var item in hh2)
        {
            double x = item * 1.5;
        }
    },
    () =>
    {
        foreach (var item in hh3)
        {
            double x = item * 1.5;
        }
    });
stop = DateTime.Now;
seleisih = stop - start;

Console.WriteLine("Start : {0}", start);
Console.WriteLine("Stop : {0}", stop);
Console.WriteLine("Selisih (tick) : {0}", seleisih.Ticks);

Console.ReadLine();

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I use console project to use it. You can try your own test

Below is the result:

This is strange since sequential is faster than parallel using AsParallel() or manually to do in parallel.

Summary: Parallelism is not always fasten the query