Critique of MSI
Bad: 2 bus ops to
load
and update a value
even
without any
sharing
•Add an
Exclusive State, opposite of Shared
PrWr/BusRdx
BusRd/Reply
PrRd/-
BusRd/-
BusRdx/--
PrRd/BusRd
PrWr/BusRdx
PrRd/--
PrWr/--
M
S
I
BusRdx/Reply
Proc
Data
Action P0 Pi Bus From
P0:r a S - BRd
Mem
P0:w a M - BRdx