Design and Verification of Adaptive Cache Coherence Protocols ...

Producer
Storel(a,v)
Commit(a)
Consumer
writeback
Memory
cache
Reconcile(a)
Loadl(a)
Figure 3.3: Producer-Consumer Synchronization in CRF
Loadl and Storel Rules: A Loadl or Storel can be performed if the address is cached in the
sache.
CRF-Loadl Rule
Site(sache, ht,Loadl(a)ipmb, mpb, proc) if Cell(a,v,-) 2 sache
! Site(sache, pmb, mpbjht,vi, proc)
CRF-Storel Rule
Site(Cell(a,-,-) j sache, ht,Storel(a,v)ipmb, mpb, proc)
! Site(Cell(a,v,Dirty) j sache, pmb, mpbjht,Acki, proc)
Although the store rule above requires that the address be cached before the Storel can
be performed, it makes no semantic di erence to allow the Storel to be performed even if the
address is not cached. This is because, if the address is not cached, the sache can rst obtain a
Clean copy from the memory (by applying the cache rule given below), and then perform the
Storel access. This can be represented by a straightforward derived rule.
Commit and Reconcile Rules: A Commit can be completed if the address is uncached or
cached in the Clean state. A Reconcile can be completed if the address is uncached or cached
in the Dirty state.
CRF-Commit Rule
Site(sache, ht,Commit(a)ipmb, mpb, proc) if Cell(a,-,Dirty) =2 sache
! Site(sache, pmb, mpbjht,Acki, proc)
CRF-Reconcile Rule
Site(sache, ht,Reconcile(a)ipmb, mpb, proc) if Cell(a,-,Clean) =2 sache
! Site(sache, pmb, mpbjht,Acki, proc)
On a Commit operation, if the address is cached and the cell's state is Dirty, the data
must be rst written back to the memory (by applying the writeback rulegiven below). On a
Reconcile operation, if the address is cached and the cell's state is Clean, the cell must be rst
purged from the sache (by applying the purge rule given below).
We can use Commit and Reconcile instructions to implement producer-consumer synchro-
nization. The memory behaves as the rendezvous between the producer and the consumer: the
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