The next few slides give an example of an update-based coherence protocol, but what is the actual definition?
cube
@sgbowen I think it's probably just any coherence protocol in which the caches actually ask other caches to update data instead of just invalidating it and having them refetch from memory.
mangocourage
What is the reason most designs today use invalidation-based protocols? Under what real-world situations/are there any specific examples of designers choosing to use update-based protocols?
kayvonf
@mangocourage: Upgrade-based protocols tend to generate significantly more interconnect traffic to implement the updates. See this slide later in the lecture as one example.
The next few slides give an example of an update-based coherence protocol, but what is the actual definition?
@sgbowen I think it's probably just any coherence protocol in which the caches actually ask other caches to update data instead of just invalidating it and having them refetch from memory.
What is the reason most designs today use invalidation-based protocols? Under what real-world situations/are there any specific examples of designers choosing to use update-based protocols?
@mangocourage: Upgrade-based protocols tend to generate significantly more interconnect traffic to implement the updates. See this slide later in the lecture as one example.