Advanced Computer Architecture Chapter 7.38
Directory Protocol
Messages
Message type Source Destination Msg Content
Read miss Local cache Home directory P,
A
Processor P reads data at address A; make P a read sharer and arrange to send data back
Write miss Local cache Home directory P, A
Processor P writes data at address A; make P the exclusive owner and arrange to send data back
Invalidate Home directory Remote caches A
Invalidate a shared copy at address A.
Fetch Home directory Remote cache A
Fetch the block at address A and send it to its home
directory
Fetch/Invalidate Home directory Remote cache A
Fetch the block at address A and send it to its home
directory; invalidate the block in the
cache
Data value reply Home directory Local cache Data
Return a data value from the home memory (read miss
response)
Data write-back Remote cache Home directory A,
Data
Write-back a data value for address A (invalidate
response)
