TPL - Using static method vs struct method

I have about 1500 files on a share for which I need to collect FileVersionInfo string. So I created a Static method in my Gateway like this:

private static string GetVersionInfo(string filepath)
{
    FileVersionInfo verInfo = FileVersionInfo.GetVersionInfo(filepath);
    return string.Format("{0}.{1}.{2}.{3}", verInfo.ProductMajorPart, verInfo.ProductMinorPart,
                                            verInfo.ProductBuildPart, verInfo.ProductPrivatePart).Trim();
}

And then used FileAndVersion struct in a PLINQ call with DegreeOfParallelism as this is I/O related

resultList = dllFilesRows.AsParallel().WithDegreeOfParallelism(20)
                    .Select(r =>
                    {
                        var symbolPath = r.Filename;
                        return new FilenameAndVersion{Filename=symbolPath, Version=GetVersionInfo(symbolPath)};
                    })
                    .ToArray();

Later I modified the Struct, FileAndVersion as:

 private struct FilenameAndVersion 
{
    private string _version, _filename;
    public string Version { get { return _version; } }
    public string Filename { get { return _filename; } }

    private void SetVersion()
    {
        FileVersionInfo verInfo = FileVersion开发者_如何学编程Info.GetVersionInfo(this.Filename);
        this._version = string.Format("{0}.{1}.{2}.{3}", verInfo.ProductMajorPart, verInfo.ProductMinorPart,

                                                                                    verInfo.ProductBuildPart, verInfo.ProductPrivatePart).Trim();
}
public FilenameAndVersion(string filename, string version)
{
    this._filename = filename;
    this._version = string.Empty;
    SetVersion();
}

}

And used it:

resultList = dllFilesRows.AsParallel().WithDegreeOfParallelism(20)
                    .Select(r =>
                    {
                        var symbolPath = r.Filename;
                        return new FilenameAndVersion(symbolPath, String.Empty);
                    })
                    .ToArray();

The question is, is this going to help me in anyway and is a good pattern to use ? Forgot to mention that the files are on a server that has RAID 10 with SAN attached to it.

Sunit

If all of your files are on the same disk, doing it in parallel isn't going to help at all. A disk can only read one thing at a time, so you would probably be better of forgetting about parallelism it, ditch the threading overhead and just let it run sequentially.

All you are going to end up with if you run this in parallel is a disk that just thrashes about all over the place and ends up reading slower overall.

If you files are on different physical drives, (or are over a network like FTP), then consider taking a bit more control of the parallelism and dividing it into a single task for each physical disk.

My advice would be to benchmark it before you make any firm commitment to making something parallel.

Using the TPL (or any form of parallelism) when dealing with file I/O is actually more likely to slow down execution than speed it up, unless you have some way to guarantee that the files being accessed in parallel are on different physical disks or on a Solid State Disk. Magnetic storage tends to be much better at sequential I/O than random-access I/O (which you are essentially forcing here).

But, as always, you need to profile and actually measure the impact of the change.

To clarify: Running expensive file operations in the background (preferably using I/O completion ports, which FileVersionInfo unfortunately does not offer) is a good thing to do, in order to avoid blocking the UI, or the ASP.NET request, depending on your environment. That is much different from running them in parallel, however; the TPL is primarily intended for parallelization of CPU-intensive tasks, where multiple CPU cores can help to complete the operation faster.