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51:50 · 27K views · Oct 26, 2021
Ian Cutress interviews Mike Clark, AMD's chief architect of Zen, about his career since the K5, how Zen began and how CPUs are designed. It also covers the future of AMD.
HN commenters point to it as a primary source from the architect of Zen, for example on how little the ISA matters compared to microarchitecture.
4 comments from Hacker News
Check out this interview with the actual architect of Zen, Mike Clark. this video Probably the most interesting nugget is that Zen2 was actually considered a tweak internally and not a full uarch revision, while Zen3 is actually the clean-sheet revision. But it's just a good summary of the general tone and tempo of CPU development I think.
Jim Keller is tied to basically every ground-breaking architecture of the last 30 years. Not that everything he's worked on has been a hit, but, if something ended up being a huge success there's a high probability Jim Keller has been skulking around somewhere. Conroe/Sandy Bridge are the only ones that come to mind that haven't been him. His greatest hits: DEC Alpha, AMD K7 (Thunderbird/Athlon), AMD K8 (Athlon 64), Apple A5, AMD Zen... probably others I'm forgetting. Like god damn can someone else in the industry have some ideas of their own please, lol /s And again not that other people aren't involved either, in particular Mike Clark was really the guy who executed Zen development, but Keller was there at least as an advisor for a lot of the early development. He's one of Zen's uncles, Clark is the father. this video I think it also says a lot that he completely fucking bailed from Intel after only being there a couple months... I think he saw they just weren't ready/willing to execute well and his time would be wasted there. He's the wandering silicon samurai who drops some golden nuggets of advice and wanders off into the sunset, not a babysitter while you purge middle-managers playing office politics.
Mike Clark, the architect of Zen says in [1] literally that ISA doesn’t matter and that it’s all about the microarchitecture. Quote: “Although I've worked on x86 obviously for 28 years, it's just an ISA, and you can build a low-power design or a high-performance out any ISA. I mean, ISA does matter, but it's not the main component - you can change the ISA if you need some special instructions to do stuff, but really the microarchitecture is in a lot of ways independent of the ISA. There are some interesting quirks in the different ISAs, but at the end of the day, it's really about microarchitecture.” In the end, ISA is such a small part that impacts the design of a modern high performance CPU that it is almost negligible. It is physically impacting only the decode unit, but the decode unit is only a few percent of die area. Feel free to listen to the whole interview to get a feeling. 1: this video
Actually, Mike Clark is the 'father of Zen': this video . When Jim came along, Zen design was mostly finished already. Another honorable mention would be Suzanne Plummer