Empy program running time

[Steven Schveighoffer]

On Fri, 29 Jul 2011 10:50:52 -0400, bearophile <bearophileHUGS at lycos.com>  
wrote:

> Steven Schveighoffer:
>
>> For example, D needs to call all the module ctors and do the import  
>> cycle
>> detection algorithm.
>
> Even for an empty program?

Yes.  I bet even an empty program has on the order of 50 module ctor/dtors  
to run.  All the runtime can contain module ctor/dtors, and those modules  
are compiled in no matter what.  Plus dmd adds hidden modules with  
ctor/dtors.

There are other initializations, such as the GC, setting up the main  
thread, etc.

>> 0.11 seconds is not unreasonable.
>
> It means about 170_000_000 CPU clock ticks, to me it seems a lot.

I guess if you want to have an empty program benchmark?  It doesn't seem  
to mean much to me...

If it was on the order of seconds, I'd agree with you.  .11 seconds is  
barely noticeable.

>> But I'll also stress that timings at this precision can be fairly  
>> volatile.
>
> I think this timing precision is not so bad.

What I mean is, the timing for a program can easily vary by 10ths of a  
second between runs, depending on what's happening on the computer.  Make  
sure you do an average, and not a single run to do these kinds of tests.

-Steve