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Kryo is not a from scratch design. It is most likely based on the A72. Qcom purchased an ARM architecture level license, which grants it access to the design o
by robert_foss 3y ago
Kryo is not a from scratch design.
It is most likely based on the A72. Qcom purchased an ARM architecture level license, which grants it access to the design of ARM CPUs and allows it to make changes and sell the resulting product. This is what Kryo most certainly is.
This is how Apple started doing ARM CPU designs as well.
- mst 3y agoAccording to the article, the original Kryo was a Qualcomm design but they're using the same branding for ARM CPU designs now. Plus original Kryo seems to be more than sufficiently different on pretty much every axis that if it -was- in part based on an ARM design I'm not sure how much of said design would be left. (people curious about this should probably read the whole thing though since this isn't exactly my area)
- clamchowder 3y ago(author here) It is not based on A72. Kryo doesn't have anything in common with A72 besides understanding the same instructions. I covered that in detail in the article. Kryo is wider and has a very different out of order engine than A72. Not mentioned was that it doesn't inherit a lot of A72's quirks. For example, A72 has peculiar decode restrictions. It can only handle one NOP per clock, and NOPs somehow consume out of order resources beyond just a ROB entry. Kryo has none of these weird characteristics.
- robert_foss 3y agoDo you think it is a from scratch design?
- clamchowder 3y agoMaybe it was built from Krait, but I'm not sure. I never tested Krait and don't have microbenchmark code written to deal with 32-bit arm