Re: [boost] [bind] performance tuning for a bad compiler

From: Michael Marcin (mmarcin_at_[hidden])
Date: 2007-12-05 16:45:50

Peter Dimov wrote:
> Michael Marcin:
> 
>> I'm trying to make local modifications to bind to improve the code
>> generated the compiler I have to use.
> 
> ...
> 
>> tester::value_type test_bind( tester& t, tester::const_reference x )
>> {
>>    return boost::bind( &tester::test, &t, _1 )( x );
>> }
> 
> I'd start with a code example that is closer to your actual use, as there is 
> no reason to use bind at all in the above. Typically boost::bind, which is 
> the inefficient part, is called once, and the (x) call is done multiple 
> times inside a for_each or similar. You might find the performance adequate 
> for some uses. There will certainly be cases where boost::bind won't cut it, 
> but you'd be able to selectively replace just those uses with handwritten 
> function objects, or even with handwritten loops.
> 
> It's not easy to optimize the general boost::bind case while still allowing 
> the tests to pass; it might be better to write a separate leaner version 
> that is more limited but still serves the majority of your specific needs. 
> 

That code started as my use case but I removed a lot of complexity to 
make it fit for consumption on the list.

Essentially it is a function object for a std::transfrom that moves 3d 
vertices from model space to view space for all vertices in a model.

The unrolled and bind version were close to identical for VC8 so I 
figured I might be able to make RVCT act right if I dropped in a few 
magic __forceinline keywords here or there. It's probably too much 
effort for me anyways so I'll just use a hand coded functor for now and 
move on.

Thanks,

Michael Marcin