LinqOptimisation Benchmarks - Count

LinqOptimisation-CountBenchmarks.cs

namespace LinqOptimisationBenchmarks
{
    [Config(typeof (BenchmarkConfig))]
    public class CountBenchmarks
    {
        private static readonly int[] items;
        static CountBenchmarks()
        {
            items = Enumerable.Range(0, 1000).ToArray();
        }

        [Benchmark(Baseline = true)]
        public int Iterative()
        {
            var counter = 0;
            foreach (var item in items)
            {
                if (item % 10 == 0)
                    counter += item;
            }

            return counter;
        }

        [Benchmark]
        [Shaman.Runtime.NoLinqRewrite] // Yay, this works!!
        public int Linq()
        {
            return items.Where(i => i % 10 == 0).Count();
        }

        [Benchmark]
        public int RoslynLinqRewrite()
        {
            return RoslynLinqRewrite_ProceduralLinq1(items);
        }

        int RoslynLinqRewrite_ProceduralLinq1(int[] _linqitems)
        {
            if (_linqitems == null)
                throw new System.ArgumentNullException();
            var _count = 0;
            for (int _index = 0; _index < _linqitems.Length; _index++)
            {
                var _linqitem = _linqitems[_index];
                if (_linqitem % 10 == 0)
                {
                    _count++;
                }
            }

            return _count;
        }

        private static readonly Func<int[], int> compiledSumQuery = Extensions.Compile<int[], int>(ps => ps.AsQueryExpr().Where(i => i % 10 == 0).Count());
        [Benchmark]
        [Shaman.Runtime.NoLinqRewrite]
        public int LinqOptimiser()
        {
            return compiledSumQuery(items);
        }
    }
}