I recently came across an example of how to use PostSharp to create a profiling aspect (source).

The following example takes advantage of the OnMethodBoundaryAspect class.

    [Serializable]
    [ProfilerAspect(AttributeExclude = true)]
    public class ProfilerAspect : OnMethodBoundaryAspect
    {
        public override void OnEntry(MethodExecutionArgs args)
        {
            args.MethodExecutionTag = Stopwatch.StartNew();
        }

        public override void OnExit(MethodExecutionArgs args)
        {
            Stopwatch sw = (Stopwatch)args.MethodExecutionTag;
            sw.Stop();

            string output = string.Format("{0} Executed in {1} milliseconds",
                                args.Method.Name, sw.ElapsedMilliseconds);

            System.Diagnostics.Debug.WriteLine(output);
        }
    }

Apply the aspect on the assembly:

[assembly: ProfilerAspect()]

If you choose to apply the aspect on the entire assembly, set the AttributeExclude to true on the aspect itself.
Don’t forget to reference the PostSharp assembly…and it’s done.