Re:Intel’s Netburst: Failure Is a Foundation for Success
by n7pdx on Sunday June 19, 2022 @12:43PM
(#31800936)
You are completely over-complicating things. P6 derivatives stuck with “traditional” Tomasulo algorithm for way too long. Everyone else moved to pointers for arch regs long before Intel did: MIPS 10k, DEC, AMD, Intel P4, etc, it isn’t really that big of a deal and is actually a simplification from the design aspect. There hasn’t been a total overhaul of CPU arch in decades.
For whatever reason, Intel called this mechanism “marbles”. There are a bunch of names in the industry for this: PRF, arch pointers, etc… its all the same thing.
By the way, moving to arch pointers is precisely what adds additional work on retirement: you need to do a walk or checkpoint restore to revert the arch state back to where it needs to be. With P6/Tomasulo, it is free. You got it backwards.
For whatever reason, Intel called this mechanism “marbles”. There are a bunch of names in the industry for this: PRF, arch pointers, etc… its all the same thing.
By the way, moving to arch pointers is precisely what adds additional work on retirement: you need to do a walk or checkpoint restore to revert the arch state back to where it needs to be. With P6/Tomasulo, it is free. You got it backwards.