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Comment by heavenlyblue | Hacker News Reader

Can you clear up whether you mean “there’s a paper that describes using neural nets” or “there’s an actual modern CPU that uses neural nets for branch brediction”?

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I originally meant "people were already doing this in the lab 19 years ago", but you are right that that does not mean CPUs "in the wild" actually do this. I originally learned about it from a blog post where someone uncapped chips to make photographs of the die and made an offhand comment about the branch prediction having neural nets.

I did some more searching and found an article at https://acad.ro/sectii2002/proceedings/doc2019-2/12-Vintan.p... which describes Samsung Galaxy S7 phones having these type of branch predictors as far back as 2016 and AMD CPUs having perceptron based branch predictors as far back as 2011. It was not officially known if Intel also uses neural networks in their chips, but the author of that paper "strongly believes" it does and I concur that it's unlikely they don't given that Samsung, Oracle, IBM, ARM and AMD all seem to use them.

AMD said back in 2016 to have a neural net predictor [1]. I found this slide following references in the Wikipedia article that rowanG077 linked below.

[1] https://cdn.arstechnica.net/wp-content/uploads/sites/3/2016/...

> Anticipate future decisions, pre-load instruction, chose best path through the CPU.

This slide is about speculative execution not necessarily about branch prediction.

Pre-loading instructions doesn't mean they're actually getting executed. It sounds like it's talking about branch prediction.

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