Re: [boost] [review] Fast track formal review of Forward library begins today

From: Joel de Guzman (joel_at_[hidden])
Date: 2007-12-06 15:49:50

Joel wrote:

>> I'd like to see more tweakable
>> parameters for specific uses. I frequently deal with
>> different number expansions in a case to case basis.
>> For example, is it possible to have arity 3 for function
>> X and arity-5 for function Y? A single number seems
>> wasteful if I'm sure that a certain use needs only a few.
>> Is that possible?
> 
> Yes, I think so. And it turns out to be a very good idea, as it
> potentially makes overload resolution *a lot* faster. Here comes the 
> benchmark compiling do_the_bind.cpp, ported to use the forward adapter 
> with gcc:
> 
>    Arity=8
>    preprocess
> 
>    real    0m1.384s
>    user    0m1.270s
>    sys     0m0.109s
> 
>    preprocess, compile, link
> 
>    real    0m12.405s
>    user    0m11.769s
>    sys     0m0.540s
> 
> 
>    Arity=4
>    preprocess
> 
>    real    0m0.918s
>    user    0m0.454s
>    sys     0m0.081s
> 
>    preprocess, compile, link
> 
>    real    0m1.949s
>    user    0m1.653s
>    sys     0m0.268s

Wow that's interesting. Is the trend exponential?
Can't really tell with just 2 sample points.

> Interestingly preprocessing is a minor concern and so we could even 
> provide means to take our pick at compile time (as opposed to 
> preprocessing time).

Not so fast. Don't forget EDG.

Regards,
-- 
Joel de Guzman
http://www.boost-consulting.com
http://spirit.sf.net