Read miss to a block in modified state 1. Read Miss by p Requestor Requesting block A Processor p Shared Cache Private Cache emory Directory 4. Data block a reply message to p 2. Fetch Block A 3. Write-Back Block A Total of 4 messages Requested by p Requested by p Processor Q writes-back Block a to shared cache Block a is shared by p and Q It is owned by shared cache Processor Q Private Cache 2021/22 计算机体系结构Read Miss to a Block in Modified State 2021/2/2 计算机体系结构 12