Michael S (already5chosen.delete@this.yahoo.com) on August 17, 2018 3:13 am wrote:
>
> I beleive it when I see it.
> This particular design team promised power efficient cores in the past. But until now never delivered.

"This particular team"? I don't recall a single design (ARM or otherwise) that actually lived up to the promises.

It may not be as bad as the ia64 promises always were, so Intel has actually been one of worst offenders, but the "future design" numbers I've seen have always been some horribly bad simulation result that don't take the memory pipeline or the TLB into account, and seem to compare some simulated Spec numbers against actual real numbers. Or something.

Even if the design itself is finalized, real hardware is simply something else. Because it turns out that the core is just a small part of the equation if you didn't actually have a real memory controller and real DRAM, but you just plugged in some optimistic numbers for "this is what the memory could do".

And then you compare with some existing chip with not "could do", but "actually does", and you look really damn good. But only in simulation - even if the simulation is supposedly cycle accurate (or, more commonly, "at least close to it").

So yeah, I'm with you on wanting actual measured numbers. Both for power and performance. And even then it's obviously going to be marketing that cherry-picks the numbers, but at least you can make some judgments by the actual benchmarks they chose to mention.

Before that it seems to be almost entirely made up.

Maybe ARM has gotten to the point where the changes are so incremental and well-understood that the expected numbers are actually fairly close to reality. But the promised big leap makes me doubt that. Whenever you promise some big leap, my gut feel is "ok, let's wait for reality to hit".

So yeah, I'd love to see an actual good A76 design. One with an actual good memory subsystem and TLB fill and reasonable IO. Something that actually would work in a laptop (or something like a NUC).

Because dammit, I want an ARM box that I can actually build and test on. Not the "yet another device that can do mobile loads and run GB".

Linus