I'm not sure if this has been asked yet, but I got curious after re-reading the slides as to whether Intel uses directory-based cache coherence. After some Googling I think I came to the conclusion that Intel uses some improved version of the MESI protocol called MESIF, but isn't documented explicitly anywhere (there's a post from 2007 about MESIF https://www.realworldtech.com/common-system-interface/5/). Directory-based cache coherence protocols seem superior to snooping-based protocols, so I was wondering why it isn't being used in recent CPUs?
EDIT: Never mind, obviously I haven't read the following slides. Surprised to see I can't google this information quite easily.
kayvonf
@cs149-zzY7C. Note that the coherence protocol (MSI, MESI, MESIF, MOESI, etC) is different from the implementation of that protocol (snooping vs. directories and combinations thereof).
I'm not sure if this has been asked yet, but I got curious after re-reading the slides as to whether Intel uses directory-based cache coherence. After some Googling I think I came to the conclusion that Intel uses some improved version of the MESI protocol called MESIF, but isn't documented explicitly anywhere (there's a post from 2007 about MESIF https://www.realworldtech.com/common-system-interface/5/). Directory-based cache coherence protocols seem superior to snooping-based protocols, so I was wondering why it isn't being used in recent CPUs?
EDIT: Never mind, obviously I haven't read the following slides. Surprised to see I can't google this information quite easily.
@cs149-zzY7C. Note that the coherence protocol (MSI, MESI, MESIF, MOESI, etC) is different from the implementation of that protocol (snooping vs. directories and combinations thereof).