anon (spam.delete.delete@this.this.spam.com) on August 10, 2019 11:25 am wrote:
>
> If Linus is interested in the 3950X as an upgrade and not the 3900X (or even 3800X) I
> highly doubt it's for the single thread performance.

I'm a big proponent of single-thread performance in general, because a lot of real-world problems really do end up being fairly limited by Amdahl.

So you'll find me often talking up single-core performance, and I absolutely despise the "flock of chickens" machines.

But realistically, Zen 2 is clearly in the "good enough" territory for anything I do on that front. It will open that huge pdf file without me twiddling my thumbs, even when that's almost entirely single-threaded. And once something performs well enough, all that I really do is build the kernel. Which is actually ludicrously well parallelized - more so than most other projects are.

So I think single-thread performance is king, but I also know that the only thing I personally do doesn't really care all that deeply. We've got a couple of link stages and a few other serialized parts, but the really expensive parts when I do a full re-build can easily use hundreds of cores.

I just don't think that because I can use hundreds of cores that that is necessarily a good fit for a lot of other real-life problems.

From a performance standpoint I could easily use server-class machines (or something like Threadripper). Or even a farm. It's just that I also want it to be quiet and a convenient form factor, and easily available. If I can't buy the parts at the local Fry's or with two-day shipping off Amazon, I'm just not interested. You can keep your bespoke stuff. I believe in mass market.

Linus