Coherence: Every memory address has an ordering for every operation. The ordering should keep the ordering of the operations from a given processor since those operations already have a clearly defined order. A read operation should given back the last value given by a write operation. Therefore, nothing like the example on lecture 10, slide 5 should occur if we have coherence. These rules only apply for a given memory address. There is no rules on how operations in two separate memory addresses should occur relative to each other.
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LeeK
Question: In the diagram on the right, P0 reads 5 after P1 writes 25. Is this suppose to be an example of when write is not propagated in time for the read? What does this mean about coherency?
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kayvonf
@Leek. Slide typo. The last line should be: P0 read 25 (sorry)
Coherence: Every memory address has an ordering for every operation. The ordering should keep the ordering of the operations from a given processor since those operations already have a clearly defined order. A read operation should given back the last value given by a write operation. Therefore, nothing like the example on lecture 10, slide 5 should occur if we have coherence. These rules only apply for a given memory address. There is no rules on how operations in two separate memory addresses should occur relative to each other.
This comment was marked helpful 0 times.
Question: In the diagram on the right, P0 reads 5 after P1 writes 25. Is this suppose to be an example of when write is not propagated in time for the read? What does this mean about coherency?
This comment was marked helpful 0 times.
@Leek. Slide typo. The last line should be: P0 read 25 (sorry)
This comment was marked helpful 0 times.