Reindl Harald wrote:
well, who's to say that we stay forever on a level of CPU
feature-support while there are instruction sets available for a whole
decade which improve performance, save power in case you need fewer
instructions doing the same work?
not that i say Fedora should go ahead and build with -mavx but a
discussion about SSE3 in 2015 is really odd
Sorry, but hardware simply does not get replaced instantly. This is a matter
of both:
* cost – hardware is not free (as in beer),
* ecology – there are huge landfills in China, India and Africa full of
electronic trash from Europe and the USA; that gets mined for
recyclable materials in an extremely polluting way that not only
ruins the environment, but also damages the health of the people
doing the mining (and the most dangerous materials are handled
by children). Materials used for electronic components are
precious, someone has to recycle them or they would run out
pretty soon.
As a developer who writes mathematical software for a living, I'd love being
able to require AVX-512 right now (
https://en.wikipedia.org/wiki/AVX-512 –
finally a way to specify the rounding mode per operation
(
https://en.wikipedia.org/wiki/EVEX_prefix) rather than through the
extremely expensive stateful fesetround operations that reset the whole
prefetch queue, interval arithmetic should become MUCH faster with that),
but I have to deal with real-world CPUs that are here NOW (so it might make
sense to have runtime detection for AVX-512 only in 1 or 2 years, and
requiring it is simply not possible within the next decade).
Kevin Kofler