Re: [boost] [parameter] Compile-time performance

Subject: Re: [boost] [parameter] Compile-time performance
From: Domagoj Saric (dsaritz_at_[hidden])
Date: 2011-02-26 13:07:37

"Dave Abrahams" <dave_at_[hidden]> wrote in message 
news:m262s6r9pi.wl%dave_at_boostpro.com...
> I think you don't understand how MPL maps work and you missed the
> mechanism in Boost.Parameter.  Therefore, I think you don't understand
> the source of the slowdown.

It might well be so...but...the slowdown almost disappeared when I replaced 
argument packs with mpl::maps...and the only thing that I know of that went 
with along with that change is the type requirements checking...so it's 
either arg-pack lookup or the requirement checking...

> We gave that approach serious consideration and would of course have
> preferred to do it that way.  I don't recall the reasons we decided 
> against it.

That's what comments are for :P
Perhaps it was exactly compile time performance (i.e. you wanted more 
descriptive names, e.g. template_keyword instead of mpl::pair, and that 
would require wrapping mpl types which incurs additional 
instantiations...)...

>> Well, the first step I guess would be to disable type requirement 
>> validation
>> and measure the difference...
>>
>>
>> ps. have you used SW's template profiler (with B.P.) ?
>
> Not yet.

Well if you are really into trying to improve Boost.Parameter the two 
obvious things to try is the elimination of the requirement checks and SW's 
template profiler...I am willing to help however I will not be by my work 
computer for the next 10 days...

-- 
"What Huxley teaches is that in the age of advanced technology, spiritual
devastation is more likely to come from an enemy with a smiling face than
from one whose countenance exudes suspicion and hate."
Neil Postman