Making byLine faster: we should be able to delegate this

[rumbu via Digitalmars-d]

On Monday, 23 March 2015 at 15:00:07 UTC, John Colvin wrote:

> What would be really great would be a performance test suite 
> for phobos. D is reaching a point where "It'll probably be fast 
> because we did it right" or "I remember it being fast-ish 3 
> years ago when i wrote a small toy test" isn't going to cut it. 
> Real data is needed, with comparisons to other languages where 
> possible.

I made the same test in C# using a 30MB plain ASCII text file. 
Compared to fastest method proposed by Andrei, results are not 
the best:

D:
readText.representation.count!(c => c == '\n') - 428 ms
byChunk(4096).joiner.count!(c => c == '\n') - 1160 ms

C#:
File.ReadAllLines.Length - 216 ms;

Win64, D 2.066.1, Optimizations were turned on in both cases.

The .net code is clearly not performance oriented 
(http://referencesource.microsoft.com/#mscorlib/system/io/file.cs,675b2259e8706c26), 
I suspect that .net runtime is performing some optimizations 
under the hood.