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Cerebras Inference: AI at Instant Speed

cerebras.ai

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Re: Cerebras Inference: AI at Instant Speed

#51

70b runs on 4x CS-3 estimated at $2-3m each, let’s say total system cost $10m, drawing ~100kW power. They don’t mention batch size, so let’s start with batch size 1 and see where we get. At 100% utilisation for 3 years that’d be 42 billion tokens for a cost of $10m capital plus ~$0.5m power and cooling let’s say, or $250 per million tokens. They’re claiming they can sell their API access at $0.60/million. To break ev…

batch size by Q4 will be solid double digits (cerebras employee)

Re: Cerebras Inference: AI at Instant Speed

#52
post #35

Earlier quoted context omitted.

That's totally nuts. How do they deal with the silicon warping around disabled cores or dark silicon? How long of hard running does it take before the chip gets fatally damaged and needs to be replaced in their system? Word on the street is that h100s fail surprisingly often, this can't be better

Is this all mostly a heat spreader efficiency requirement?

I suppose the proper term would be heat spreader thermal resistance limit, dictated by the thermal stress sums or whatever the term would be.

Re: Cerebras Inference: AI at Instant Speed

#53

Earlier quoted context omitted.

That's totally nuts. How do they deal with the silicon warping around disabled cores or dark silicon? How long of hard running does it take before the chip gets fatally damaged and needs to be replaced in their system? Word on the street is that h100s fail surprisingly often, this can't be better

edit: I should have just checked their website instead of guessing. Apparently WSE has significant fabrication challenges, which makes what Cerebras has accomplished all the more impressive. But it is still surprising that no one else has attempted this in the HPC field. I had guessed that Cerebras had made some trade-offs in process in order to make it work at scale, but then they aren't actually building these devi…

It shouldn't be surprising. It's hard as fuck, and we don't know if it's worth it yet (there's something to be said for "if your compute dies you send your remote hands to swap out a high four figure component" and not "decommission a high-six-figure node"

Re: Cerebras Inference: AI at Instant Speed

#55
post #43
post #13

It would be understandable that they are focused currently on inference speed, but features like structured output and prompt caching make it possible to build more capable LLM applications. Does Cerebras support reliable structured output like the recent OpenAI 4o?

They are running stock Llama 3.x. If the underlying models support structured output, so will they. For example, I know the latest batch of Mistral models all have json output support.

Structured output is a token picker feature, not (just) a model feature.

Re: Cerebras Inference: AI at Instant Speed

#57

Can really fast inference (e.g. 1M tok/sec) make LLMs more intelligent? I am imagining you could run multiple agents and can choose and discard outputs using other LLMs simultaneously. Will the output look more like a real thought process? Or will it remain just same?

Not just that, but you could have a network of LLM's all talk and discuss a answer before answering at this sort of speed. Literally could have it generate internal thoughts and challenges to itself before responding via scripting.

Re: Cerebras Inference: AI at Instant Speed

#59

Earlier quoted context omitted.

edit: I should have just checked their website instead of guessing. Apparently WSE has significant fabrication challenges, which makes what Cerebras has accomplished all the more impressive. But it is still surprising that no one else has attempted this in the HPC field. I had guessed that Cerebras had made some trade-offs in process in order to make it work at scale, but then they aren't actually building these devi…

It shouldn't be surprising. It's hard as fuck, and we don't know if it's worth it yet (there's something to be said for "if your compute dies you send your remote hands to swap out a high four figure component" and not "decommission a high-six-figure node"

I hope I didn't make it sound like it was easy, at least I don't think I said that anywhere. It doesn't really matter how hard something is to do (short of it being trivially proven impossible), it matters whether there's a good enough chance that the payoff exceeds the cost.

And actually there have been attempts to do it, I mentioned in an earlier version of my comment that Gene Amdahl had attemped to make WSE work something like 20 years ago, without success - but also without the clear profitability story of AI to attract the same mountains of cash being thrown around today.

What's surprising is not that it is hard, or that it's hard as fuck, but that given the potentially stratospheric rewards for success there have not been more attempts in this direction.

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