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Editorial Team
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Asked: 2026-06-03T03:46:38+00:00

How to make my i7 processor reach 100% usage with this code? Is there

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How to make my i7 processor reach 100% usage with this code? Is there something special that happens in the XmlDocument? is just because of the context change? and if so why putting more threads wouldnt make the the processor use its full power? what would be the fatest way to parse several strings at a time?

EDIT:

Maybe this code will make it more clear, no matter what number of threads it uses 30% of the processor:

    private void Form1_Load(object sender, EventArgs e)
    {
        Action action = () =>
        {
            while (true)
            {
                XmlDocument xmlDocument = new XmlDocument();

                xmlDocument.LoadXml("<html><body><div>1111</div><div>222</div></body></html>");
                var nodes = xmlDocument.SelectNodes("//div");
            }
        };

        Parallel.For(0, 16, i => action());
    }
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1 Answer

  1. Editorial Team

    In your code sample (and you would see this with a profiler) you are wasting a LOT time waiting for available resources to run those threads. Because you are constantly requesting more and more Parallel.For (which is a non-blocking call) – your process is spending significant time waiting for threads to finish and then the next thread to be selected (an ever growing amount of such threads all requesting time to run).

    Consider this output from the profiler:

    The RED color is synchronization! Look how much work is going on by the kernel to let my app run so many threads! Note, if you had a single core processor, you’d definitely see 100%

    enter image description here

    You’re going to have the best time reading this xml by splitting the string and parsing them separately (post-load from I/O of course). You may not see 100% cpu usage, but that’s going to be the best option. Play with different partition sizes of the string (i.e. substring sizes).

    For an amazing read on parallel patterns, I recommend this paper by Stephen Toub: http://download.microsoft.com/download/3/4/D/34D13993-2132-4E04-AE48-53D3150057BD/Patterns_of_Parallel_Programming_CSharp.pdf

    EDIT I did some searching for a smart way to read xml in multiple threads. My best advice is this:

    1. Split your xml files into smaller files if you can.
    2. Use one thread per xml file.
    3. If 1&2 aren’t sufficient for you perf needs, consider not loading it as xml completely, but partitioning the string (splitting it), and parsing a bit by hand (not to an XmlDocument). I would only do this if 1 and 2 are good enough for your needs. Each partition (substring) would run on its own thread. Remember too that “more threds” != “more cpu usage”, at least not for your app. As we see in the profiler example, too many threads costs a lot of overhead. Keep it simple.
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