15 January 2007
Lampson: Lazy and Speculative Execution
25
Speculative: Exponential backoff
nSchedule
a resource without central control
oEthernet
oWiFi (descended from Aloha packet radio, 1969)
oSpin locks
nThe
idea
oTry to access resource
oDetect collision, wait randomly and retry
oBack off exponentially, adapting to load
nThe
bet: No collision
nGood
performance needs collision < hold time