Re: [Gems-users] Some Problems about the MOESI_directory cache coherence protocol

[Greg Byrd <gbyrd@xxxxxxxx>]

1. When I reading the MOESI_directory-cache.sm file, I noticed there are some words like "GetX", "GetS" and "PUT", and I am wondering what is the particular meaning of these words? 

"GETS" = "GET shared"?? "GETX" = "GET exclusived"?? I am not sure about it, especially what is the particular meaning of "PUT"?

Yes.  PUT is a writeback.

 

2. Because I am not very familiar with the MOESI_directory protocol, I want to know which kind of message will be sent to multiple destinations? I know the invalidate message maybe needed to send to multiple destinations. But I am not sure whether there are still other message types need to send to multiple destinations? 

Only invalidation messages need to be sent to multiple destinations.

 

3. Whether the invalidation message are always forwarded by the directory node? 

Invalidates messages are always sent by the directory, because it's the only entity that knows who all the sharers are.

...Greg