O Write Miss to a Block with Sharers Requestor 1. Write Miss by p Requesting block A Processor p Shared Cache Private Cache Memory Directory 5. Data block a reply message to P 2. Invalidate A Directory sends invalidate messages to all sharers Processor Q Private Cache Directory receives acknowledge message for all invalidates and 3. Invalidate A clears their presence bits dooo3o Directory sends data reply Processor r message, and changes state of Private Cache block a to modified 2021/22 计算机体系结构Write Miss to a Block with Sharers 2021/2/2 计算机体系结构 15