15 January 2007
Lampson: Lazy and Speculative Execution
26
Speculative: Caching
nKeep
some data
oin the hope that you will use it again,
oor you will use other data near it
nThe
bet: Data is reused
nTypically
cost is fairly small
oBut people depend on winning
obecause cost of miss is 100x – 1000x
nBet
yields a big win in latency and bandwith
o>100x in latency today
oSave expensive memory/disk bandwidth