By: Linus Torvalds (torvalds.delete@this.linux-foundation.org), July 12, 2013 9:16 am
Room: Moderated Discussions
Mark Roulo (nothanks.delete@this.xxx.com) on July 11, 2013 4:19 pm wrote:
> Michael S (already5chosen.delete@this.yahoo.com) on July 11, 2013 3:59 pm wrote:
> > the discussion was about absence of AVX in Silvermont
>
> I'm hijacking it a bit because Linus claimed that AVX is "esoteric"
I also very much talked about "engineering tradeoffs".
In a big core, you can go wild. I mentioned in the whole original AVX thread (where I said that FP performance doesn't actually matter for most loads once you've gotten at least *some* kind of reasonable baseline) that in a big core, once you've done all the work for the things that matter (integer and memory), and if you have the resources, you might as well splurge them on the stuff that doesn't really matter but makes you look good in benchmarks and makes a couple of people happy.
So go wild in the big cores. As long as AVX doesn't slow down anything else, who cares about the extra effort and transistors? Nobody.
But I still don't think that AVX makes sense in a small chip. The engineering trade-offs just aren't there.
Linus
> Michael S (already5chosen.delete@this.yahoo.com) on July 11, 2013 3:59 pm wrote:
> > the discussion was about absence of AVX in Silvermont
>
> I'm hijacking it a bit because Linus claimed that AVX is "esoteric"
I also very much talked about "engineering tradeoffs".
In a big core, you can go wild. I mentioned in the whole original AVX thread (where I said that FP performance doesn't actually matter for most loads once you've gotten at least *some* kind of reasonable baseline) that in a big core, once you've done all the work for the things that matter (integer and memory), and if you have the resources, you might as well splurge them on the stuff that doesn't really matter but makes you look good in benchmarks and makes a couple of people happy.
So go wild in the big cores. As long as AVX doesn't slow down anything else, who cares about the extra effort and transistors? Nobody.
But I still don't think that AVX makes sense in a small chip. The engineering trade-offs just aren't there.
Linus