[arch-dev-public] x86_64: improving default CFLAGS

[Roman Kyrylych]

2007/4/4, Andreas Radke <a.radke at arcor.de>:
> Am Tue, 3 Apr 2007 16:40:20 -0500
> schrieb "Aaron Griffin" <aaronmgriffin at gmail.com>:
>
> > > > to not break backward compatibility for those few early cpus that
> > > > lack SSE3 extensions we want to do it with -mtune. this is how we
> > > > want to set it for the future:
> > > >
> > > > CFLAGS="-march=x86-64 -mtune=nocona -O2 -pipe"
> > > > CXXFLAGS="-march=x86-64 -mtune=nocona -O2 -pipe"
> >
> > I don't know the details, so I assumed you looked into it all.  Just
> > in case: what 64bit processors does this "leave in the dust".
> >
> > Dropping support for some processors is not a huge problem (the age
> > old Via C3 + Arch problem), but i think it might be important to put a
> > blurb somewhere saying "If you have an XYZ processor, you need to use
> > the arch i686".
> >
>
> i don't want to drop support for any early x86_64 cpu.
>
> that's why i want to use "mtune". code will be optimized for SSE3
> capable cpus but will still run on non SSE3 capable processors. that's
> the difference mtune to march.
>
> i686 had something similar prepared in the old makepkg.conf
>
> i don't expect a big gain at all but in certain multimedia apps it can
> speedup things a lot. so why not make use of the additional registers?
> apps *might* run a little bit slower if they cannot make use of the
> additional flags and will it probably raise the pkg size a bit. but it
> should be still worth it.

I don't mind mtune (I've read forum thread).

-- 
Roman Kyrylych (Роман Кирилич)