Here is the shell of some code and a typical pattern:

foreach (var s in masterList)

{

    // Do some work with s

}

You can very easily convert this to use the parallel extensions by using the following code:

Parallel.ForEach(masterList, s =>

{

    // Do some work with s

}

);

So the code change is easy, but what is the difference?

Well you should certainly consider how much work you are doing for each message – short simple tasks probably won’t benefit from being parallel.

You should also consider how much IO is performed against storage etc. – the more IO performed the more you will benefit from using the extensions.

But David PLEASE GIVE ME SOME FIGURES.

Ok – here is the low down.

The code I have reads some data from a collection (loaded from a blob) then writes a row into table storage for each item in the collection. There is a total of 748 items in the collection spread across 7 partitions.

Without the parallel extension the results look like this across 3 identical runs:

No I don’t know what happened to the last one, but its around ~35 seconds or about 21 entities per second.

With the parallel extensions the results are:

That is a tad faster at ~14 seconds or about 53 entities per second (probably faster as I’m being generous here).

The tests were all done using a small VM size (1 core) and the tables etc. were deleted between tests. It’s not terribly scientific, but its good enough to show its worth looking into.

For a simple code change, that is not a bad days work.

You can find out some more about the extensions at http://msdn.microsoft.com/en-us/library/dd460693.aspx as well as the C9 10-4 show at http://channel9.msdn.com/shows/10-4/10-4-Episode-6-Parallel-Extensions/.

THIS POSTING IS PROVIDED “AS IS” WITH NO WARRANTIES, AND CONFERS NO RIGHTS, NOBODY EVER READS THIS BIT EITHER SO I DON’T EVEN KNOW WHY I BOTHER SOMETIMES