15 January 2007
Lampson: Lazy and Speculative Execution
10
Performance
and Scheduling
nTwo
factors
oBet on the outcome of the conditional
oMore concurrency (pays if you have extra
resources)
nBandwidth
(total cost of doing work)
oLess work to do if you win the lazy bet
oMore concurrency when lazy, or if you win the speculative
bet
▬Good
if you have idle resources, which is increasingly likely
nLatency
oFaster results from A when lazy: L; !A Þ !A; L
oFaster results from S with concurrency: A; S Þ S || A