| You're both right. What the GP is saying is that all the details of how modern processors work are out there in books and academic papers, and that the material covered in graduate-level computer architecture courses is very relevant and helpful, and they include all (or nearly all) the techniques used in industry. From the GP's perspective, it doesn't matter at all if the course taught branch predictors on a MIPS processor, even though MIPS isn't really used anywhere anymore (well, that's wrong, they're used extensively in networking gear, but y'know, for the argument). They still go over the various techniques used, their consequences, etc., so the processor chosen as an example is unimportant. You're saying that all this information is unhelpful for you, because what you want is a detailed optimization guide for a particular CPU with its own particular implementation of branch prediction. And yeah, university courses don't cover that, but note that they're not "outdated" because it's not as if at some point what they taught was "current" in this respect. So yeah, in this sense you're right, academia does not directly tackle optimization for a given processor in teaching or research, and if it did it would be basically instantly outdated. Your best resource for doing that is the manufacturer's optimization guide, and those can be light on details, especially on exactly how the branch predictor works. But "how a processor works" is a different topic from "how this specific processor works", and the work being done in academia is not outdated compared to what the industry is doing. PS: Never believe the marketing in the press release, yeah? "Neural network" as used here is pure marketing bullshit. They're usually not directly lying, but you can bet that they're stretching the definition of what a "neural network" is and the role it plays. |
They also include various techniques not used anymore, without mentioning that’s the case. I did a search for “branch predictor static forward not taken site:.edu” and found many documents which discuss that particular BTFN technique. In modern CPUs the predictor works before fetch or decode.
> university courses don't cover that
Here’s a link to one: https://course.ece.cmu.edu/~ece740/f15/lib/exe/fetch.php?med... According to the first slide, the document was written in fall 2015. It has dedicated slides discussing particular implementations of branch predictors in Pentium Pro, Alpha 21264, Pentium M, and Pentium 4.
The processors being covered were released between 1995 and 2003. At the time that course was written, people were already programming Skylake and Excavator, and Zen 1 was just around the corner.
I’m not saying the professor failed to deliver. Quite the opposite, information about old CPUs is better than pure theory without any practically useful stuff. Still, I’m pretty sure they would be happy to included slides about contemporary CPUs, if only that information was public.