Deep inside ARM's new Intel killer

http://www.theregister.co.uk/2011/10/20/details_on_big_little_processing/

by protomyth • 15 years ago

54 42 15 years ago

theregister.co.uk

jws• 15 years ago

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.

sounds6• 15 years ago

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...

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.

ChuckMcM• 15 years ago

Ars had a better take on it, but that is to be expected.

I was reminded of how MIPS used to be the best selling ISA but that was because it was in HP and Lexmark printers so tons were sold and nobody realized it.

The tablet/smartphone markets have really pushed ARM into a position where the shear number of implementations justifies the time and effort to build better software. The helps the architecture achieve better tool parity and that is something that is vital for its longevity.

rbanffy6• 15 years ago

> because it was in HP and Lexmark printers

And game console. PS1, PS2 and N64, IIRC, were MIPS boxes.

Symmetry• 15 years ago

On the other hand, this will probably head of MIPS's attempts to encroach on ARM's markets.

sounds6• 15 years ago

I'd really like to know if MIPS is actually competitive at the same performance-per-watt levels as ARM.

As I understand it, MIPS is easy to license and cheap to build, so when cost is the biggest factor you go with MIPS. That's nothing to sneeze at.

The way I see it ARM dominates in phones and tablets because these devices do much more than, say, a wireless router.

salem3• 15 years ago

ARM, especially ARM-thumb mode, is the gold standard for instructions/watt. That's why it's in phones since way back. I don't see MIPS challenging that.

rbanffy6• 15 years ago

> They have different origins, different goals, and different areas of expertise.

The greatest threat against Intel is the decreasing importance of the PC and the increasing importance of tablets, überphones and other non-Intel-based devices. Intel is common on desktops because the most popular OS for desktops runs on nothing but an x86 and on servers largely because what we call a server these days is just a (sometimes exquisitely) well built PC with rack mounting rails that has to be a PC because a very popular server OS can't run on anything that's not an x86 PC.

So, as x86's vanish from desks, there will be less reason to run desktop-derived OSs on servers and less reason to run them on x86 servers. With Windows 8 there is even less reason to have x86's in the remaining desktops, users being able to opt for more power-efficient ARM engines. I am not sure whether Windows Server 8 will support ARM-based servers, but, if they do, I expect the x86 to become a legacy platform.

sounds6• 15 years ago

I'll chime in on the "Post-PC Era" buzzword ... but only with a disclaimer: I don't buy it.

Intel wants to grow their market, so they're investing in UMPCs and MIDs. I think it's pretty telling they aren't in any phones (yet). They're going to try that in 2012.

Ok. "Post PC?" I don't buy it. PCs may change to ARM, but there will always be IT, science, engineering, data visualization, education, ... -- stuff that might work on a phone or a tablet, but the keyboard is a "killer app."

I actually see the two markets as symbiotic. Only in corner cases can you find people who prefer a smartphone over a PC, or vice versa. It looks like mainstream applications benefit from having both.

InclinedPlane5• 15 years ago

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• 15 years ago

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?

jseliger• 15 years ago

Because tech writers need something to write about, and rises and falls are more exciting that coexistence. I got tired of reading endless "PCs are dying, so run out and buy more stuff!!!11" articles and decided to write a response to them: http://jseliger.com/2011/10/09/desktop-pcs-arent-going-anywh... that's applies to the analogous situation you bring up.

ippisl• 15 years ago

According to the article , intel's strength is in per thread performance.But most of today's heavy applications enjoy multi-thread performance: Multi-user servers, Heavy math applications and other applications written with today's better multi-programming tools.

So that means selling a lot less chips.

But that bad for intel's business model , and get worse with moore's law(they gotta sell double number of transistors).

Now about demise: it's hard to tell because it depends minimum sales intel needs to sustain it's business model, But intel are trying to counteract that with several interesting moves:

1. An integrated pc platform strategy: CPU+GPU integration , chipsets with better integration with their flash modules(z86 chipset), buying an anti-virus software. This way they can get more money and have more control on the pc market. This may compensate them on decreasing volumes. And hurt GPU manufacturers along the way. 2. Finding new sources for chip manufacturing r&d investments: Manufacturing flash, letting non-competing companies manufacture chips using intel fabs. 3. trying hard to compete on the multi-core performance game: letting old code(c++/fortran, etc) run faster on a 64-core intel platfrom might be more appealing than needing to import that code to a GPU.Working on parallel development tools also helps there.

corysama• 15 years ago

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

cpeterso• 15 years ago

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.

salem3• 15 years ago

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

ZeroGravitas• 15 years ago

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

bitwize• 15 years ago

"big.LITTLE processing".

Funniest name since Blast Processing.

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

6ren2• 15 years ago

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>

flazzarino• 15 years ago

There exists a non-intuitive asymmetry in the nature of systems like multi-core. Do four 10mph car crashes do the same damage as one 40mph crash? If it can be properly coordinated. If you can coordinate it, how much does the coordination cost? At worst you only have the power of one 10mph crash, often at best too.

Programming for multi-core can a hard problem but the problem doesn't always lie in our abilities, many times it's computationally impossible.

To play games and video is a must right? We want the most from our battery right? A fact of the situation is that high power activities are many times mutually exclusive from low power activities right? So what is awful, inelegant or stupid about the design? The asymmetry? There is asymmetry of the interaction? Should you cary around a dumb-phone, a gameboy, and a video player? Maybe more elegant, but it sure is more awful.

P.S. Don't talk about FP son ;)

Someone• 15 years ago

"Do four 10mph car crashes do the same damage as one 40mph crash? If it can be properly coordinated."

I know this is totally unrelated, but it is worth correcting: potential energy is 1/2 m v^2, so that faster car has 16 times the potential energy as each of the slower cars. That is why braking distances do not go up linearly with car speed and why high speed accidentals are way more lethal than low speed ones.

I guess there is an analogy here that one double-speed CPU beats two single-speed ones for most tasks, but I do not think it is very apt.

grannyg00se• 15 years ago

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.

6ren2• 15 years ago

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...?

cjenkins• 15 years ago

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• 15 years ago

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.

dstein• 15 years ago

Intel already bought and then sold an ARM licensee:

http://en.wikipedia.org/wiki/XScale

Deep inside ARM's new Intel killer

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