On Sat, Nov 7, 2015 at 7:23 PM, Reindl Harald <h.reindl@xxxxxxxxxxxxx> wrote: > > > Am 07.11.2015 um 19:01 schrieb Kevin Kofler: >> >> 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) > > > that *really* depends > > these days (and i talk about hardware from 2011) you can virtualize things > fast, easy and efficient and consolidate machines on more or less cheap > hardware > > besides it brings new CPU capabilities it saves a lot of energy: > > * one machine instead 2,3,4 or 10 machines > * the new hardware needs so much less power > * your UPS (in case you use one) can be cheaper or lasts longer > * cooling is easier, cheaper and not that loud > > some numbers in that context: > > in early 2010 we planned a UPS systems to last for around 3 hours, with the > current hardware and after consolidation the same UPS lasts 9 hours now and > the air conditioner has lower load and longer lifetime > > the same applies to consumer hardware, my 365/7 running homeserver from 2011 > is a power beast and the whole IT needs around 50W while the previous > hardware needed 120W - that's money, that's heat on summer days, that's less > noise and hardddisks don't need to replaced that often because they are > cooler > >> * 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. > > > that is true but see above > >> 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) > > > maybe you did not get "not that i say Fedora should go ahead and build with > -mavx" but we talk about SSE3 Compiling everything with sse3 does have a cost (dropping support for some hardware) but what does it gain us? Better performance in theory? To convince anyone you have to at least provide numbers. Otherwise the discussion is a waste of time. -- devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxxx https://admin.fedoraproject.org/mailman/listinfo/devel Fedora Code of Conduct: http://fedoraproject.org/code-of-conduct
