Re: glibc recompile - optimized for G5 cpu target

[Mathieu Malaterre <malat@debian.org>]

On Tue, Jan 5, 2016 at 1:02 AM, Peter Saisanas <psaisanas@gmail.com> wrote:
> Hi,
> This has been playing in my mind for a while and wondering if i could get
> some feedback from others.
>
> I assume glibc typically available in the Debian repo's has been compiled
> for a generic ppc32 target and the ricer in me wants to try and extract some
> more performance.

Per documentation of ld.so:

[...]
HARDWARE CAPABILITIES
       Some libraries are compiled using hardware-specific
instructions which do not exist on every CPU.  Such libraries should
be  installed  in  directories  whose  names  define  the
       required  hardware capabilities, such as /usr/lib/sse2/.  The
dynamic linker checks these directories against the hardware of the
machine and selects the most suitable version of
       a given library.  Hardware capability directories can be
cascaded to combine CPU features.  The list of supported hardware
capability names depends on  the  CPU.   The  following
       names are currently recognized:


       PowerPC
              4xxmac,  altivec,  arch_2_05,  arch_2_06, booke, cellbe,
dfp, efpdouble, efpsingle, fpu, ic_snoop, mmu, notb, pa6t, power4,
power5, power5+, power6x, ppc32, ppc601, ppc64,
              smt, spe, ucache, vsx
[...]

So you could simply use that directory and leave the original glibc
untouched in case something goes really wrong.