Qualcomm Says Eight-Core Processors Are Dumb

itwbennett writes "Following rival MediaTek's announcement of plans to release an eight-core processor in the fourth quarter, Qualcomm has declared eight-core processors 'dumb'. 'You can't take eight lawnmower engines, put them together and now claim you have an eight-cylinder Ferrari. It just doesn't make sense,' Qualcomm's senior vice president Anand Chandrasekher said, according to a transcript of his comments to Taiwan media provided on Friday. Asked whether Qualcomm would one day launch its own octa-core processor, Chandrasekher said, 'We don't do dumb things.'"

Comments

The Onion said it best

[Nimey]

Fuck everything, we're doing five blades.

http://www.theonion.com/articles/fuck-everything-were-doing-five-blades,11056/ ...and then someone made one with five blades, and it's better enough that people will buy it.

Re:The Onion said it best

[Golddess]

Reminds me of a TV commercial from a while back, put out by one razor blade company, to make fun of another razor blade company for continually adding additional blades. I seem to recall that not long after those ads started airing, they disappeared, and the first company began adding additional blades as well.

Re:The Onion said it best

[Dracos]

More metal blades doesn't make a better razor after 2 or 3. After that, the manufacturers are just one-upping each other to keep the marketing going.

I'd gladly pay much more for a razor with only two ceramic blades. But that'll never happen, because metal razor blades are by definition planned obsolescence.

Re:The Onion said it best

[GNious]

Actually-having-facial-hair race here, and I've yet to see an electric razor able to come close to "smooth-as-sandpaper", let alone as smooth as a proper Wilkinson blade will do it.

Re:The Onion said it best

[Anonymous Coward]

Your mom gave me a rash...

Re:The Onion said it best

[mcmonkey]

You are allowed 5 free articles (or views) of The Onion website. After that they greet you with a paywall. One day, you are going to hit that limit. Your face is going to be annoyed once that happens.

That's perfect. The Onion only has 5 ideas that they keep recycling/repackaging.

Re:The Onion said it best

[chill]

Grow a set and use a straight razor like God intended. Nothing focuses your mind in the morning like the possibility of accidental suicide.

If you REALLY want to wake up, use one in the shower. You'll be VERY careful about dropping it.

Re:The Onion said it best

[Anonymous Coward]

On the other hand, Qualcomm is probably saying 8-cores is stupid, because they don't have one on the market. Wait to hear what they say when they come up with one.

No, they're saying they're stupid because they really are stupid. There is little demand for more than 2 cores in today's (or tomorrow's) mobile software. 2 cores is the sweet spot, 4 is questionable, 8 is brazenly pandering to people who have no clue.

The other thing is that the Samsung chip isn't even a genuine 8-core device. To be sure, there are a total of eight physical ARM cores present, but by design you're only intended to use four at a time. There are two clusters of four cores. One is a Cortex-A15 cluster (fast, high power, occupies lots of die area), the other is Cortex-A7 (slow, low power, small). This is a concept that ARM Holdings markets as "big.LITTLE". They don't have any core designs with a sufficiently wide dynamic range of power/performance operating points, so they're compensating by telling customers (like Samsung) that they should design in a redundant set of cores of a different design which can reach the desired power consumption targets. Firmware running below the OS decides which cluster should be active at any given time, and manages handoffs and powerdown of the inactive cluster. It's a very inelegant kludge, especially since the handoffs cause performance hits.

Qualcomm and Apple both have high performance homegrown ARM core designs which scale down to lower power states better than A15, though they're not quite as fast as A15 on the top end. Hence, both of them are offering dual-core parts, since as long as your individual cores are fast two, is pretty much enough for the vast majority of mobile software. Apple is particularly focused on maximizing performance to power ratio, since they focus exclusively on building small (no 5" screens), thin, and light phones, yet they still want to be close to the top in real world performance and also among the best in battery life.

Both of them could be shipping 4+ cores right now if they thought it was worth it. Once you've gone to two cores, adding more is fairly simple, since all the mechanisms for maintaining cache coherency between multiple cores have already been worked out. But they don't think it's worth it so they haven't done it.

Samsung, on the other hand, needs something to hang their hat on. Unlike Qualcomm they can't integrate radios into their SoCs (yet, but they're working on it), which is a huge disadvantage. And they don't (yet, but they're working on it) have their own custom ARM core design. So they're trying to differentiate their current products using the hand they've been dealt, which presently means using ARM's big.LITTLE concept to offer absurd core counts that aren't actually useful to end users, and a bunch of other questionable things.

qualcomm is right

[Xicor]

eight core processors are dumb. though not for the reason he gave. they are dumb because nothing supports 8 cores, so 99% of the time, the extra 2-6 cores are totally wasted. if the software would catch up to the hard ware, we might see more use in 8+ cores

Re:qualcomm is right

[PhxBlue]

And I suppose 640k is enough for anybody, too?

Re:qualcomm is right

[Samantha Wright]

The reason he gave was one step ahead of that: even if you get apps that can use all eight cores, it's going to be murder on battery life, and most of the cost will be wasted (because most apps won't be using all that core power still.)

Re:qualcomm is right

[MachineShedFred]

I would think that a highly multithreaded app combined with a highly parallel CPU would actually be more power efficient, as you're doing the same work in less clocks.

Granted, all tasks cannot be highly multithreaded, but that particular street goes both ways.

Re:qualcomm is right

[Billly Gates]

You're just missing vision. Imagine Ubuntu Phone on an 8 core processor, you could have it run virtual machines and seamlessly switch between Android, Windows Phone, BlackBerry, IOS... who doesn't want that?

Plus you'd still have enough oomph to run a torrent server, a tor node or just use your phone to mine some bitcoins.

And your phone will be out of battery life by the time you unplug it and show up to work

Re:qualcomm is right

[a1cypher]

Parallelization does introduce it's own overhead. Some problems can be made to run parallel very easily without much effort. For example, lets say you have an unordered database of names and you want to count how many letter "A"s are in each name. You can very easily divide the database into eight equal parts and send it off to eight cores for processing and they will happily churn away until you have your answer with almost no additional overhead.

However, different problems cant be as easily parallelized. For example, lets say you take the same database of names and you want to sort it alphabetically. You can send each chunk of the database off to be sorted on each core, but now you have 8 pieces of the database that are all sorted and need to be merged back into the original list. This extra work of merging and communicating becomes the overhead.

This is a very simple example, but for many problems the speed gained by parallelization is reduced for every new thread. So you might get an almost 50% speedup by adding a second core, but the third core will give you maybe only 20% speedup, and the fourth 15%, etc...

And as mentioned by others, parallelization is almost always done to improve performance, not efficiency. It would be more power efficient for the one core to do the job if you are measuring efficiency by something like cycles per watt. This doesnt make much sense in a mobile device whose paramount concern is to run a long time on a battery.

Not that I disagree...

[Opportunist]

...but every time some company says something is dumb, this usually means one of three things:

1) Our competitor has too many patents so we can't make it
2) We can't reach the quality/price of our competitor or
3) Not the product is too dumb, we're just too dumb to produce it.

VM

[Taibhsear]

And my virtual machines say, "Shut your pie hole, Chandrasekher."

Similar quote from Seymour Cray

[Crash McBang]

If you were plowing a field, which would you rather use? Two strong oxen or 1024 chickens?

Re:I'll say it

[tlhIngan]

Anyway, I think ol Qualcomm is lacking a certain basic understanding of what multicore architecture brings to the table. Er, phone. Desktop. Tablet. Whatever.

But that's ok. Manufacturers that remain mired in the past fall to their competitors and so self-select themselves out of the game.

Except Qualcomm has a point.

An 8 core SoC has 4 powerful A15-ish cores, and 4 power efficient A7-ish cores. Now, ARM's big.LITTLE allows for OS awareness of all 8 cores and their asymmetry, or you can treat it as a 4-core system and perform a direct switch.

The reason for this is the A15 is a power hog. It's fast, but it turns energy into heat very quickly. The A7 is slower, but turns less energy into heat. When you're gaming, you want the big beefy cores to give you maximum FPS goodness or whatever, then when you're back to listening ot MP3s, switch it for the power sippers.

Now, Qualcomm has skin in the game in that their 4 core Kraits are able to do DVFS on each individual core (so each core runs as fast as it needs to be, and no faster), which means it doesn't need a secondary batch of slower processors because it can run the main ones slower and more power efficiently..

Of course, what 8-core purveyors DON'T mention is you cannot run all 4 A15 cores for more than a few minutes at a time - you'll destroy the SoC because it overheats. That's how bad the A15s are. If you can use 2 A15s and keep the other 2 idle, for the most pare, you can do this forever. But put some load in and you'll need to throttle the A15s - 100-100-50-50% at first, and if temperatures still aren't cooling, start throttling the slower ones even more, turning them off if need be.

And in phones there's no space for the heatsink and fan, and often there's a PoP memory on top, so you can't even stick a heatsink on if you wanted.

Thermal management is extremely important on these octacores. especially as the system can't be cooled traditionally.

Until Qualcomm makes a server chip, they do have a point - what's the point of quad or octacore if you're not able to keep them running at full load because the hardware is limiting the speed?

Of course, anyone will know that benchmarks only run for a few minutes at a time. Aggressive core management also helps (switching to A7s as much as possible to keep the chip cooler).