Benchmarking method calls in C#

Question

I'm looking for a way to benchmark method calls in C#.

I have coded a data structure for university assignment, and just came up with a way to optimize a bit, but in a way that would add a bit of overhead in all situations, while turning a O(n) call into O(1) in some.

Now I want to run both versions against the test data to see if it's worth implementing the optimization. I know that in Ruby, you could wrap the code in a Benchmark block and have it output the time needed to execute the block in console - is there something like that available for C#?

Answer 1

You could use the inbuilt Stopwatch class to "Provides a set of methods and properties that you can use to accurately measure elapsed time." if you are looking for a manual way to do it. Not sure on automated though.

Answer 2

Sounds like you want a profiler. I would strongly recommend the EQATEC profiler myself, it being the best free one I've tried. The nice thing about this method over a simple stopwatch one is that it also provides a breakdown of performance over certain methods/blocks.

Answer 3

I stole most of the following from Jon Skeet's method for benchmarking:

private static void Benchmark(Action act, int interval)
{
    GC.Collect();
    Stopwatch sw = Stopwatch.StartNew();
    for (int i = 0; i < interval; i++)
    {
        act.Invoke();
    }
    sw.Stop();
    Console.WriteLine(sw.ElapsedMilliseconds);
}

Answer 4

Profilers give the best benchmarks since they diagnose all your code, however they slow it down a lot. Profilers are used for finding bottlenecks.

For optimizing an algorithm, when you know where the bottlenecks are, use a dictionary of name-->stopwatch, to keep track of the performance critical sections during run-time.

Answer 5

Stolen (and modified) from Yuriy's answer:

private static void Benchmark(Action act, int iterations)
{
    GC.Collect();
    act.Invoke(); // run once outside of loop to avoid initialization costs
    Stopwatch sw = Stopwatch.StartNew();
    for (int i = 0; i < iterations; i++)
    {
        act.Invoke();
    }
    sw.Stop();
    Console.WriteLine((sw.ElapsedMilliseconds / iterations).ToString());
}

Often a particular method has to initialize some things, and you don't always want to include those initialization costs in your overall benchmark. Also, you want to divide the total execution time by the number of iterations, so that your estimate is more-or-less independent of the number of iterations.