A Closer Look (Write) I
On a write access
fault at Px, the local directory controller checks if the block is
locally/remotely allocated; if remote it finds the home
•Controller
sends request to home node for blk
•Home
controller looks up directory entry of blk
–Dirty
bit OFF, the home has a clean copy
•Home
node sends data to Px w/presence vector
•Home controller clears directory, sets xth bit ON and sets dirty bit
ON
•Px controller sends invalidation request to all
nodes listed in the presence vector