On Jul 22, 2019, at 1:21 PM, Solomon Peachy
> On Mon, Jul 22, 2019 at 04:11:32PM -0400, Stephen Gallagher wrote:
> With my FESCo hat on, I can't support this action as currently stated.
> I think I'd be more inclined to consider it if the Change was proposed
> as a new architecture bring-up. Effectively, this would be a whole new
> architecture that would just happen to be largely compatible with
Now that approach makes a lot more sense!
And we could easily do some apples-to-apples system benchmarks to see if
there's any meaningful improvements to be had.
IMO this approach is wrong. There’s nothing special about AVX1. There
are plenty of packages that can be built with various CPU extensions
on or off but that don’t have runtime detection. and Fedora should
have the ability to straightforwardly build multiple variants. Sure,
this might involve some rpm and dnf fiddling, but that’s nothing
compared to creating a whole new architecture.
I can imagine this working in multiple ways. There could be something
akin to modules or maybe sub-architectures, where there are multiple
non-parallel-installable versions of various packages along with
tooling to say "optimize for this machine" or "optimize for the
following baseline". There could also be good tooling to build
dynamically-selected libraries (/lib/hw/avx2/libfoo.so). Fat binaries
for actual executables or some equivalent (multiple binaries with
/usr/bin/foo choosing which one to exec) could work. Some combination
could make sense.