-mtune for Glibc

[Bruce Dubbs]

Jeremy Huntwork wrote:
> Hello All,
> 
> We never really decided on what to do for -mtune on Glibc. See the end of
> Greg's post here:
> http://linuxfromscratch.org/pipermail/lfs-dev/2007-September/060338.html
> 
> And again his comments here:
> http://linuxfromscratch.org/pipermail/lfs-dev/2007-September/060338.html
> 
> My opinion is that we'd want to use -mtune=native, but I'd like to hear some
> feedback from the rest of you.

Both your links are the same...

I'm not opposed to adding some optimization into LFS.  We are, after
all, not building for a lowest capability system but we are targeting  a
custom system for each user.

That said, the discussion of optimization needs to be changed in the
Intro section to Chapter 6.  It now says:

"Also note that the -march and -mtune options may cause problems with
the toolchain packages (Binutils, GCC and Glibc). The small potential
gains achieved in using compiler optimizations are often outweighed by
the risks. First-time builders of LFS are encouraged to build without
custom optimizations. "

This seems to be at odds with the above.

  -- Bruce