
Deep inside ARM's new Intel killer - protomyth
http://www.theregister.co.uk/2011/10/20/details_on_big_little_processing/
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6ren
This is our inability to use multi-core.

From the performance graph
(<http://regmedia.co.uk/2011/10/20/arm_performance.jpg>), two A7s would have
the same raw processing power as one A15 - at less than half the power. The
problem is we can't utilize that raw power effectively. So, instead, this
awful, inelegant, stupid design is probably the absolute best we can do at the
moment.

People claim that functional programming's immutability solves this problem.
But it's interesting that while Erlang, one of the most effective multi-
processor languages, is functional, it doesn't use that for multi-core:
instead, it uses a shared-nothing architecture (like smalltalk) which is
independent of the fp paradigm; and STM (Software Transactional Memory). The
second interesting thing is that incredible rewards are available today for a
solution (and have been for a while) - so where are the fp solutions? Why
haven't they taken over, or had substantial success - or, at least, appeared?

Multi-core is a hard problem. Silicon is cheap but we don't know how to use it
(excepting GPUs/CUDA). I think this will not be solved with any existing
methods (including 50-year old fp). Instead, it will require a complete
reframing of the question, from the silicon-up. That is, it won't even _look_
like a programming language - or a computer.

It's hard to overstate the rewards for solving this.</provocativerant>

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grannyg00se
Erlang wasn't purpose built for multi-core though. It just so happens that
everything desired for ultra reliability and continuity ended up working well
for multi-core applications. The share-nothing architecture is not "for multi-
core" it is for stability and reliability. The multi-core fit is a great bonus
that happens to now be very important. Ditto for functional programming's
immutability.

~~~
6ren
True; I was commenting on what makes it good for multi-core. Share-nothing
helps; immutability doesn't (because they don't share data, unless on the same
core). Unless there's some other benefit to immutability for multi-core...?

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sounds
I enjoyed reading Ars Technica's take on this a while back, entitled "All this
has happened before: NVIDIA 3.0, ARM, and the fate of x86"

[http://arstechnica.com/business/news/2011/02/nvidia-30-and-t...](http://arstechnica.com/business/news/2011/02/nvidia-30-and-
the-riscification-of-x86.ars)

Predictions of x86's imminent demise are, well, wrong. But so too, prediciting
arm's destruction at the hands of intel... not likely.

There's lots of market for both companies. They have different origins,
different goals, and different areas of expertise.

~~~
InclinedPlane
I don't know quite why every recent competitive relationship in tech has been
portrayed as an imminent existential battle, but it's an annoying trend.

~~~
mturmon
It sucks. I think it's as simple as: page views.

Reduce the news to something as simple as possible, give people a side to
cheer for. Who would have imagined that tech would turn in to a spectator
sport?

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jws
This is the A7 mentioned yesterday. The article is worth a peek if only for
the two contrasted CPU instruction diagrams showing the difference in
complexity and the graph of performance versus power for the two chips.

It all makes sense when you see those.

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corysama
Here's ARM's whitepaper that the article links and summarizes:
<http://www.arm.com/files/downloads/big.LITTLE_Final.pdf>

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cjenkins
I've always thought it strange to think that ARM (or any other CPU design)
company could take out Intel.

Worst case in the ARM scenario, Intel buys a company with an ARM license and
is still a step ahead on process and fab technology.

To boot, increased mobile device usage (even on ARM) is probably good overall
for Intel as it helps drive demand for the servers powering the services those
devices consume.

~~~
Andys
ARM chips are priced an order of magnitude lower than Intel's chips. Their
process advantage would only last one generation because the fat profit
margins aren't there to pay for the next one.

If ARM kills Intel, its because cheap chips are finally "good enough" for
nearly all purposes.

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cpeterso
I'm curious to see how the Linux process scheduler will load balance processes
will be tweaked to use the big dog and little dog processors. IO-bound
processes could be migrated to the little dog and CPU-bound processes to the
big dog.

~~~
salem
From the description, it seemed like there is a mode to handle this
transparently in hardware

~~~
ZeroGravitas
I believe the OS can, optionally, make these decisions itself if it wants to.

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bitwize
"big.LITTLE processing".

Funniest name since Blast Processing.

I imagine little Sackboys running around my smartphone, carrying bits of soft
polyester data.

