Re: Re: ICC Profile

Ciaran McCreesh wrote:
> 
> How much of that is memory bound? Of the things that aren't, how many
> aren't written in assembly anyway? Of those things, what proportion of
> the runtime is spent in those areas?
> 
> If you double the speed of something that takes up 2% of the overall
> execution time, you can't measure the improvement.
> 
> Or looking at it the other way -- is there any reason to believe that
> using icc (which can end up being a substantial pain in the arse, given
> the way it tries to use gcc's c++ headers but doesn't support some of
> the extensions or quirks that g++ does) will provide a genuine gain
> for people who aren't already doing clever profile-directed trickery
> anyway?
> 
> 
> The problem with -O3 is that function inlining can lead to a
> substantial cache hit. Unless you're using profile-directed
> optimisations, which Gentoo doesn't support, it's extremely hit and
> miss as to whether O3 helps or hurts.
> 

I agree with all of the above.   Gentoo is about choice, so if people 
want to make ICC work well more power to them.  I agree that it would be 
hard to make it THE ONLY system compiler.  For those who do try it I'd 
be really interested in their findings.
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