Evaluating Replacement Policies
Effective Access.Time = (1-p)*Tm + p*Td
Tm = time to access main memory
Td = time to fault
Execution time = (roughly) #memory refs * E.A.T.
# of physical page frames
execution
time
Random
LRU
Opt
Down in this range,
it doesn’t matter so
much what you do.
In here, you can
expect to have some
effect.
Up here,
forget it.
Few frames
Lots of frames
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