Slow start up time of runtime

[bauss]

On Tuesday, 20 March 2018 at 12:07:12 UTC, bauss wrote:
> On Tuesday, 20 March 2018 at 10:46:11 UTC, Dennis wrote:
>> On Tuesday, 20 March 2018 at 10:20:55 UTC, Dennis wrote:
>>> On Tuesday, 20 March 2018 at 09:51:09 UTC, bauss wrote:
>>>> Besides if it was and it took 1 second to startup, then it 
>>>> wouldn't matter in practice with an actual application.
>>>
>>> This is not concerning for large applications indeed. But 
>>> say, I want to implement my own `dir` (= `ls` on Unix) in D. 
>>> Would you want to use it if it took a full second every time 
>>> you wanted to quickly view a folder's contents?
>>
>> To give some more context, I've been using some of the digital 
>> mars utilities and I admire their speed. A `grep -r "goto" 
>> *.d` could find and scan 1.7 MB of d-source files in 190ms, 
>> way before my D hello-world was even able to enter main. As 
>> far I know, these are just C programs. I wonder if I could 
>> make such fast utilities in D, or whether (idiomatic) D is not 
>> the right tool for this and I should use (better)C instead.
>
> Have you tried other applications that doesn't just print and 
> see if that matters?
>
> Try to write to a file instead of the standard output and see 
> if that makes any difference between each compilation unit.
>
> Also remember that you don't compile with dmd for runtime 
> speed, but compilation speed. For runtime speed you want to use 
> ldc, since it optimizes code way better.

To add on to this.

Typically dmd is better during development, ldc is better during 
deployment and release.