
Apple Purchases Another Processor Design House - razerbeans
http://arstechnica.com/apple/news/2010/04/report-apple-purchases-another-processor-design-house.ars
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MikeCapone
Question for the CPU-savvy people here:

Would there be any advantage in making a desktop computer that ran on the ARM
architecture (instead of x86)?

Power consumption seems to be the obvious one; would it be possible to ramp up
the performance of ARM to match modern x86 but while keeping a power-
efficiency bonus?

Maybe with OpenCL/Grand Central/etc you could have an ARM-based desktop that
used minimal power most of the time, spreading the work over many slower low-
power cores, and used the GPU when heavy lifting is required..?

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halo
Apple seem to be keeping a close eye on LLVM which would allow architecture-
independent binaries with relatively little penalty.

I'm not an expert in the field, but I suspect that x86 will continue to offer
the best value in terms of performance relative to cost, which is the most
important factor to consider in desktop computing. However, having the option
to run the same binaries on other architectures opens the door for using other
architectures on handheld, low-powered, or small-form-factor devices, where
factors other than performance matter and Apple may be able to compete
favourably.

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1amzave
I think it goes a bit beyond "keeping a close eye on"...

Apple's employed Chris Lattner (the creator/primary author of LLVM) for a
number of years now, and I think LLVM is widely regarded as being a pretty
major part of their plans going forward. (And it's not just Apple, either --
Nvidia's using LLVM for their OpenCL implementation, for example.)

As for x86 vs. ARM...in the high-performance single-core/multi-core area (up
to say, 8 cores or so), I think x86, ugly as it is, is likely to remain
entrenched. There have been a hell of a lot of dollars and man-hours pumped in
to making it (single-threaded) fast over the last couple decades, and in that
area it may actually have some technical advantages over a cleaner ISA (such
as ARM, though ARM isn't exactly the epitome of RISC purity). Two things off
the top of my head -- a) the instruction encoding, as insane as it is, allows
pretty dense code, meaning good I-cache utilization, and b) the two-operand
instruction format simplifies dependency-checking and forwarding logic, for
which hardware costs run O(n^2) (where n is proportional to operands-per-
instruction and issue width).

In the "manycore" area though, I think the power and area costs of decoding
the x86 ISA will be a more significant disadvantage (this may have something
to do with why the power consumption of Larrabee prototypes was rumored to be
so enormous). Tilera, for example, makes manycore chips based on MIPS, which
I'd say is a somewhat cleaner ISA RISC-wise (meaning better-suited for
small/efficient hardware implementation) than ARM.

So, if manycore is indeed the future, I'd say there is definitely hope for
avoiding a completely x86-monopolized world...

