Building optimized packages, including kernel

[Ross Boylan <RossBoylan@stanfordalumni.org>]

Hi.  I hope I'm in the right place.

Since I'm going to be building a bunch of programs anyway, I would
like to build packages optimized for my particular machine, with the
compiler getting -march=athlon as well as -O3 (unless the latter is
not safe; I'm using gcc 2.95.4).

What is the debian way to do this when I'm building packages from
source?

And, using kernel-package, how do I build kernels and modules
appropriately?  Should I build packages that have subarchitecture
names? 

I notice in particular that debian has an architecture concept meaning
the different architectures we support (e.g., sparc, s/390 ....) and I
don't want to inadvertently mess with that.  I saw an older post that
messing with /usr/bin/dpgk-architecture is not the way to go.

By the way, I believe it is safe to mix code I've optimized with regular
unoptimized libraries (i.e., regular debs).  Let me know if not.  I
also understand that I can't mix code from different versions of gcc,
at least not C++ from 3.2.  So I should stick with 2.95 unless I want
to rebuild every package I use--correct?

Thanks in advance for any guidance.

P.S. Does anybody know if the optimizations are likely to make any
difference?  I've started doing stuff with graphics, and it is
noticeably slow.