Tuning make.conf

[Marcin Koziuk]

Luca Presotto wrote:
> Hi everyone!
> 	I was starting to think to recompile everything for my pc to speed 
> up everything. I started googling and I found almost nothing about how to 
> change make.conf on bsd. Almost everything was about Gentoo, somehow not 
> unsurprisingly.
> The first thing I noticed is that for linux all the instructions are about 
> doing CFLAGS=" value" while it seems from /etc/share/examples/make.conf 
> that in bsd I don't need ". Is it correct?
> Second question: If I set MAKEOPTS= -j 3 will that be used when 
> portupgrading? (It's really to slow otherwise!)
> Third question...The most difficult..Which are the best flags for my 
> machine? (freebsd 7.0-RELEASE with an intel centrino core2 duo)
> I have seen in the ..../examples/etc/make.conf that one of the possible 
> "CPUTYPE" is core2 which looks to me as the right one but a geekier friend 
> of mine that lives inside gentoo-linux told me that this option is 
> unknown is gcc 4.2 and will be working from gcc4.3, so he told me to use 
> "prescott".
> And what do I have to set to make gcc aware of the type of CPU I have?
> CPUTYPE= cpu
> and then CFLAGS= --O2 -pipe (etc..)
> or should I not write the cputype and then do:
> CLFAGS= -march=mycpu --O2 etc....
> Can someone give me some advice on how to configure this file?
> Or can you provide me some documentation?
> Thank you!
>
>
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>
You're *really* wasting your time. The whole thing about those compiler 
optimizations is a myth. And most ports are already compiled with -O2 by 
default IIRC. But why would you spend two days compiling for a 0.1% 
speed increase? Your system is doing no cpu cycles at all for most of 
the time anyway. And I really wouldn't recommend aggressive 
optimizations for stuff like the kernel. Disabling unnecessary services 
or installing apps you often use without support for X and Y (like 
installing KDE or Gnome base, then the apps you *really* want on top of 
it) will give you much better performance than messing with CFLAGS and 
such. Also, makeopts and -pipe just make _compiling_ faster, not the 
applications themselves!!!.
Please take a look at the following pages, they have a lot more 
information about this matter ;)
http://funroll-loops.info/
http://bugs.gentoo.org/show_bug.cgi?id=74072

--
- Marcin