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426 points benchmarkist | 10 comments | | HN request time: 0.637s | source | bottom
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zackangelo ◴[] No.42179476[source]
This is astonishingly fast. I’m struggling to get over 100 tok/s on my own Llama 3.1 70b implementation on an 8x H100 cluster.

I’m curious how they’re doing it. Obviously the standard bag of tricks (eg, speculative decoding, flash attention) won’t get you close. It seems like at a minimum you’d have to do multi-node inference and maybe some kind of sparse attention mechanism?

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danpalmer ◴[] No.42179501[source]
Cerebras makes CPUs with ~1 million cores, and they're inferring on that not on GPUs. It's an entirely different architecture which means no network involved. It's possible they're doing this significantly from CPU caches rather than HBM as well.

I recommend the TechTechPotato YouTube videos on Cerebras to understand more of their chip design.

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accrual ◴[] No.42179717[source]
I hope we can buy Cerebras cards one day. Imagine buying a ~$500 AI card for your desktop and having easy access to 70B+ models (the price is speculative/made up).
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danpalmer ◴[] No.42180050[source]
I believe pricing was mid 6 figures per machine. They're also like 8U and water cooled I believe. I doubt it would be possible to deploy one outside of a fairly top tier colo facility where they have the ability to support water cooling. Also imagine learning a new CUDA but that is designed for another completely different compute model.
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1. bboygravity ◴[] No.42180470[source]
That means it'll be close to affordable in 3 to 5 years if we follow the curve we've been on for the past decades.
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2. schoen ◴[] No.42180845[source]
How have power and cooling been doing with respect to chip improvements? Have power requirements per operation been coming down rapidly, as other features have improved?

My recollection from PC CPUs is that we've gotten many more operations per second, and many more operations per second per dollar, but that the power and corresponding cooling requirements for the CPUs have tended to go up as well. I don't really know what power per operation has looked like there. (I guess it's clearly improved, though, because it seems like the power consumption of a desktop PC has only increased by a single order of magnitude, while the computational capacity has increased by more than that.)

A reason that I wonder about this in this context is that people are saying that the power and cooling requirements for these devices are currently enormous (by individual or hobbyist standards, not by data center standards!). If we imagine a Moore's Law-style improvement where the hardware itself becomes 1/10 or 1/100 of its current price, would we expect the overall power consumption to be similarly reduced, or to remain closer to its current levels?

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3. dheera ◴[] No.42180967[source]
It will also mean 405B models will be uninteresting in 3 to 5 years if we follow the curve we've been on for the past decades.
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4. chaxor ◴[] No.42180977[source]
Mooers law in the consumer space seems to be pretty much asymptoting now, as indicated by Apple's amazing Macbooks with an astounding 8GB of RAM. Data center compute is arguable, as it tends to be catered to some niche, making it confusing (cerebras as an example vs GPU datacenters vs more standard HPC). Also Clusters and even GPUs don't really fit in to Mooers law as originally framed.
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5. saagarjha ◴[] No.42181319{3}[source]
Apple doesn’t sell those anymore.
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6. int_19h ◴[] No.42181405[source]
I don't think they'll be uninteresting. They won't be cutting-edge anymore, sure, but much of the more practical applications of AI that we see today don't run on today's cutting-edge models, either. We're always going to have a certain compute budget, and if a smaller model does the job fine, why wouldn't you use it, and use the rest for something else (or use all of it to run the smaller model faster).
7. dgfl ◴[] No.42181580[source]
Not really. These are wafer-scale chips, which (as far as I'm aware) were first introduced by Cerebras.

Cost reduction for cutting-edge products in the semiconductor industry has historically been driven by 1) reducing transistor size (by following the Dennard scaling laws), and 2) a variety of techniques (e.g. high-k dielectrics and strained silicon, or FinFETs and now GAAFETs) to improve transistor performance further. These techniques added more steps during manufacturing, but they were inexpensive enough that they allowed to reduce $/transistor still. In the last few years, we've had to pull off ever more expensive tricks which stopped the $/transistor progress. This is why the phrase "Moore's law is dead" has been circulating for a while.

In any case, higher performance transistors means that you can get the same functionality for less power and a smaller area, meaning that iso-functionality chips are cheaper to build in bulk. This is especially true for older nodes, e.g. look at the absurdly low price of most microcontrollers.

On the other hand, $/wafer is mostly a volume-related metric based on less scalable technology and more conventional manufacturing (relatively speaking). Cerebra's innovation was in making a wafer-scale chip possible, which is conventionally hard due to unavoidable manufacturing defects. But crucially, such a product (by definition) cannot scale like any other circuit produced so far.

It may for sure drop in price in the future, especially once it gets obsolete. But I don't expect it to ever reach consumer level prices.

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8. adrian_b ◴[] No.42182481[source]
Wafer-scale chips have been attempted for many decades, but none of the previous attempts before Cerebras has resulted in a successful commercial product.

The main reason why Cerebras has succeeded and the previous attempts have failed is not technical, but the existence of market demand.

Before ML/AI training and inference, there has been no application where wafer-scale chips could provide enough additional performance to make their high cost worthwhile.

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9. chaxor ◴[] No.42184690{4}[source]
Aw man, are they selling only 4GB ones now?

More seriously, even 16GB was essentially the 'norm' in consumer PCs about 15 years ago.

10. ryao ◴[] No.42190978{3}[source]
Cerebras has a patent on the technique used to etch across scribe lines. Is there any prior work that would invalidate that patent?

By the way, I am a software developer, so you will not see me challenging their patent. I am just curious.