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Breakthrough: The Secret to Making Processors 1,000 Times Faster

mashable.com

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Re: Breakthrough: The Secret to Making Processors 1,000 Times Faster

#91

Post by rbanffy »

sparky wrote: post #89
ori_b wrote: post #86

Earlier quoted context omitted.

We're talking about cache, where the addresses of blocks in cache do not have a 1:1 mapping with addresses in memory. Read the section on associativity: http://en.wikipedia.org/wiki/CPU_cache

You get to choose your associativity, you could build a direct-mapped 1GB L1 cache if you wanted. More fundamentally, a memory's access time grows with its capacity because the average and worst-case distances from a bitcell to the read/write port are longer.

If you pack enough memory in the same package and connect it to the CPU through a bus that's fast enough, on-chip memory that used to be used for caches can get promoted to main memory and off-chip RAM becomes a fast cache for your SSDs and a way to synchronize context between different chip stacks.

Put the GPU and VRAM on the stack and all you need is a couple HDMI ports going out of the chip.

Re: Breakthrough: The Secret to Making Processors 1,000 Times Faster

#92

Post by rbanffy »

sparky wrote: post #89
ori_b wrote: post #86

Earlier quoted context omitted.

We're talking about cache, where the addresses of blocks in cache do not have a 1:1 mapping with addresses in memory. Read the section on associativity: http://en.wikipedia.org/wiki/CPU_cache

You get to choose your associativity, you could build a direct-mapped 1GB L1 cache if you wanted. More fundamentally, a memory's access time grows with its capacity because the average and worst-case distances from a bitcell to the read/write port are longer.

If you pack enough memory in the same package and connect it to the CPU through a bus that's fast enough, on-chip memory that used to be used for caches can get promoted to main memory and off-chip RAM becomes a fast cache for your SSDs and a way to synchronize context between different chip stacks.

Put the GPU and VRAM on the stack and all you need is a couple HDMI ports going out of the chip.

Re: Breakthrough: The Secret to Making Processors 1,000 Times Faster

#93

Post by marshray »

starwed wrote: post #13

So this is a way of dissipating heat more efficiently, such that chips can be apparently be stacked on top of each other -- does that really help all that much for consumer (and especially mobile) stuff? Seems like you're still generating the same total amount of heat, that needs venting from the machine. And still consuming the same amount of power. I'm sure there's some value here, but it's not going to arise from…

I don't see how stacking chips would do anything but make the heat dissipation problem much much worse. There is no magical "heat dissipating adhesive", only substances that conduct heat better or worse.

A conventional chip is a thin planar heating element attached with maximal surface area to its heat sink and we have great trouble keeping them cool now.

Heat generated internally a cubic object is more difficult to remove because the volume that is generating heat grows faster in proportion to the surface area available for removing it. I.e., the heat generation grows with the cube of the unit length and the surface only with the square).

The worst shape of all is spherical which has the highest possible ratio of volume to surface area.

Even if they managed to put heat sinks in contact with all six sides of this stack of dies, they could (at best) only remove six conventional chips' worth of heat.

Unless they have a way of circulating liquid coolant through that volume, stacking chips like that is only practical if they're almost completely off.

Re: Breakthrough: The Secret to Making Processors 1,000 Times Faster

#94

Post by marshray »

spitfire wrote: post #87

Great. But the IO is still orders of magnitudes away from the processor. Faster CPU's are important in several areas, but for 99% of problems it's RAM and stable storage that are the bottleneck.

I think the they'd want to incorporate RAM into the stack as well. (not that I think the premise is sound)

Re: Breakthrough: The Secret to Making Processors 1,000 Times Faster

#95

Post by marshray »

burgerbrain wrote: post #26
shithead wrote: post #15

Reality check: this is total bullshit. A miracle glue will not solve power dissipation problems, not even if it were a perfect thermal conductor.

It's not a miracle, it's science. And if they can back it up, it doesn't matter if you find it inconceivable.

I didn't see any science in that video. I just saw total PR BS.

Re: Breakthrough: The Secret to Making Processors 1,000 Times Faster

#96

Post by keeperofdakeys »

rbanffy wrote: post #91
sparky wrote: post #89

Earlier quoted context omitted.

You get to choose your associativity, you could build a direct-mapped 1GB L1 cache if you wanted. More fundamentally, a memory's access time grows with its capacity because the average and worst-case distances from a bitcell to the read/write port are longer.

If you pack enough memory in the same package and connect it to the CPU through a bus that's fast enough, on-chip memory that used to be used for caches can get promoted to main memory and off-chip RAM becomes a fast cache for your SSDs and a way to synchronize context between different chip stacks. Put the GPU and VRAM on the stack and all you need is a couple HDMI ports going out of the chip.

Cache is already about as fast as you can get without significant compromises in size. L1 cache runs at speeds fast enough that increasing the size (and average seek time), or increasing the distance the signal has to travel, will decrease access times significantly. So it doesn't become about how 'fast' the bus is, or how much memory you can pack on.

Re: Breakthrough: The Secret to Making Processors 1,000 Times Faster

#97

Post by rbanffy »

keeperofdakeys wrote: post #96
rbanffy wrote: post #91

Earlier quoted context omitted.

If you pack enough memory in the same package and connect it to the CPU through a bus that's fast enough, on-chip memory that used to be used for caches can get promoted to main memory and off-chip RAM becomes a fast cache for your SSDs and a way to synchronize context between different chip stacks. Put the GPU and VRAM on the stack and all you need is a couple HDMI ports going out of the chip.

Cache is already about as fast as you can get without significant compromises in size. L1 cache runs at speeds fast enough that increasing the size (and average seek time), or increasing the distance the signal has to travel, will decrease access times significantly. So it doesn't become about how 'fast' the bus is, or how much memory you can pack on.

Putting a good chunk of memory between the processor and the external memory bus would allow interconnection through a much faster bus than the external one, reducing the penalty of a cache miss.

Re: Breakthrough: The Secret to Making Processors 1,000 Times Faster

#98

Post by sliverstorm »

rbanffy wrote: post #97
keeperofdakeys wrote: post #96

Earlier quoted context omitted.

Cache is already about as fast as you can get without significant compromises in size. L1 cache runs at speeds fast enough that increasing the size (and average seek time), or increasing the distance the signal has to travel, will decrease access times significantly. So it doesn't become about how 'fast' the bus is, or how much memory you can pack on.

Putting a good chunk of memory between the processor and the external memory bus would allow interconnection through a much faster bus than the external one, reducing the penalty of a cache miss.

The two of you are arguing about different things. You are arguing the point of increasing cache to reduce misses. The other guy is arguing that increasing cache size will degrade cache performance as a unit. These are distinct arguments.

Re: Breakthrough: The Secret to Making Processors 1,000 Times Faster

#99

Post by dcx »

sek wrote: post #40
zeteo wrote: post #29

This is a poorly written, sensationalistic article. Here's the original press release: http://www-03.ibm.com/press/us/en/pressrelease/35358.wss Basically, this is about IBM and 3M starting a new research project. Whether it would work, how long it would take, at what cost - these are all open questions.

There is a lot of sensationalist PR from IBM. The Cat Brain, the Smarter Planet thing, the AI processor and now a 1k times faster processor..... some arbitrary stuff an nothing concrete. I wonder what this PR strategy should accomplish and who is the target for this.

I noticed this too. My theory is it's brand image-building to differentiate their enterprise offerings from say, Accenture or Deloitte. Most of their revenue currently comes from enterprise software and hardware. To a 50-year-old C[EI]O who doesn't look too deeply into tech any more, I'm sure this feels like a nice throwback to their innovations in the past few decades.

Re: Breakthrough: The Secret to Making Processors 1,000 Times Faster

#100

Post by xyzzyz »

michaelchisari wrote: post #3

3D game programming in pure Python, anyone? :) If this is real (and since it's IBM and they're claiming production by 2013, I'm optimistic), this is going to be a huge game changer on so many levels.

This does not look like a big win for Python, since it's most likely to provide you with ludicrous amount of computing cores, and Python currently is a bad tool for concurrent computing.
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