Question

I’m using a few functions like

    ICollection<ICache> caches = new HashSet<ICache>();

    ICollection<T> Matches<T>(string dependentVariableName)
    {
        return caches
            .Where(x => x.GetVariableName() == dependentVariableName)
            .Where(x => typeof(T).IsAssignableFrom(x.GetType()))
            .Select(x => (T) x)
            .ToList();
    }

in my current class design. They work wonderfully from an architecture perspective–where I can arbitrarily add objects of various related types (in this case ICaches) and retrieve them as collections of concrete types.

An issue is that the framework here is a scientific package, and these sorts of functions lie on very hot code paths that are getting called thousands of times over a few minute period. The result:

and functions like the above are the main consumers of the COMDelegate::DelegateConstruct.

As you can see from the relative distribution of the sample %, this isn’t a deal breaker, but it would be fantastic to reduce the overhead a bit!

Thanks in advance.

Answer 1

1) i dont see how the code you posted it related to the performance data… the functions listed dont look like they are called from this code at all. so really i can’t answer your question except to say that maybe you are interpreting he performance report wrong.

2) don’t call .ToList at the end… just return the IEnumerable. that will help performance. only do ToList when you really do need a list that you can later add/remove/sort things in.

3) i dont have enough context but it seems this method could be eliminated by making use of the dynamic keyword