Where is Apple headed?

By: Maynard Handley (name99.delete@this.name99.org), November 25, 2018 10:47 am
Room: Moderated Discussions
There's been some interesting chat on Twitter about next year's Apple core.
Here's what's definite:
There is a core codenamed Lightning, part of a SoC named T8030.
And the boot process generates statements like these:

How can we interpret these? This is something of a summary of discussions, and represents a few different viewpoints. Mine will probably stand out, but others (including those who acquired the screenshots and codenames) disagree with me about some aspects.

There are two interesting issues here:

(a) The codename. Obviously it's NOT a variant on "big wind".

- Obviously this could be as meaningless as when Apple switched the OS from cat names to cal names, because they ran out of cats. Reasonable, but uninteresting.

- It signals a new "base design" for the iPhone/iPad cores. The Vortex strain has done incredibly well since good old Cyclone, but for years now Apple has been designing a true successor, as opposed to (substantial!) annual improvements, and it's ready to be released?

- The third possibility arises from the question: "suppose you have a 45W budget for your SoC rather than 5W. What do you do?" Beyond the obvious answer (more cores), you can mindlessly crank up the frequency for a few 100MHz till you hit your power budget, but you all know what I think of that! So suppose that you take your baseline iPhone/iPad core but re-optimize the size of all the various structures (BTB, TLB, number of physical registers, ...) based on high-performance (rather than low-power) transistor timings? This could give you a fourth tier to Apple's cores: giving us, let's call them
Vortex+, Vortex, Tempest, and Chinook-class.
We can then mix and match these across devices, so, eg, MacBookPro gets
4Vortex+ + 4Vortex +4 Tempest; iPad gets 1+4+4; iPhone gets 0+2+4.

(b) The screen shots. AFT? Trace buffer?
MY assumption is that this is NOT the trace cache of P4; this is obviously a bespoke piece of *RAM*.
The most likely concept, IMHO, is something like Michael Ferdman's Temporal Streaming prefetcher https://t.co/mrEX9XrF4I
This is a prefetcher that achieves astonishing accuracy -- at the cost of large storage requirements, large enough to require off-chip storage of the meta-data.
The assumption, then, is that AFT refers to something like Apple Fetch Trace, or Apple Fetch Technology.
A secondary possibility (but doesn't line up as well with the nomenclature we see) is something like total (transparent) memory compression that's handled by the memory controller. (As opposed to the current, page-based, OS-visible) scheme. Such compression would also need somewhere to store metadata (and may well be coming) but, like I said, these screen shots lean a lot more, IMHO, to the enhanced prefetch side.
 Next Post in Thread >
TopicPosted ByDate
Where is Apple headed?Maynard Handley2018/11/25 10:47 AM
  Where is Apple headed?Doug S2018/11/25 12:06 PM
    Where is Apple headed?never_released2018/11/25 12:44 PM
    Where is Apple headed?Kevin G2018/11/25 01:07 PM
    Where is Apple headed?Maynard Handley2018/11/25 01:59 PM
      Where is Apple headed?Anne O. Nymous2018/11/25 03:08 PM
        Where is Apple headed?Maynard Handley2018/11/25 04:51 PM
          Where is Apple headed?Anne O. Nymous2018/11/26 07:15 AM
  Where is Apple headed?Dan Strother2018/11/25 12:54 PM
    Where is Apple headed?Maynard Handley2018/11/25 01:50 PM
      Where is Apple headed?anon2018/11/25 07:39 PM
        Where is Apple headed?Maynard Handley2018/11/25 08:42 PM
          Where is Apple headed?anon2018/11/25 09:09 PM
  Where is Apple headed?Kevin G2018/11/25 01:51 PM
    Where is Apple headed?Maynard Handley2018/11/25 02:11 PM
      Where is Apple headed?Brett2018/11/25 07:46 PM
  Memory compressionFoo_2018/11/26 04:35 AM
    Memory compressionDoug S2018/11/26 11:24 AM
      Memory compressionMaynard Handley2018/11/26 01:10 PM
Reply to this Topic
Body: No Text
How do you spell purple?