In class, I didn't quite understand the answers to these, and I'm not positive I understand what the problem was on the prior slide (is it that 2 and 3 send lots of requests for the lock, presumably emulating busy-waiting, and also repeatedly invalidate the line owned by 1?). I felt rather lost during this example and was hoping that somebody might be able to help clarify these.
jinglim2
Observe that test-and-set involves writing, hence there will be significant amount of cache-coherence driven traffic between processor 2 and 3 who are taking turns to get the line.
In class, I didn't quite understand the answers to these, and I'm not positive I understand what the problem was on the prior slide (is it that 2 and 3 send lots of requests for the lock, presumably emulating busy-waiting, and also repeatedly invalidate the line owned by 1?). I felt rather lost during this example and was hoping that somebody might be able to help clarify these.
Observe that test-and-set involves writing, hence there will be significant amount of cache-coherence driven traffic between processor 2 and 3 who are taking turns to get the line.