TBPM’s supplement on device drivers
Four problems:
- Requesters are generated by multiple tasks. TBPM uses the knowledge from OS kernel to separate tasks
- Tasks are created, executed and terminated. (DD has know knowledge on multiple tasks and their termination)
- Tasks have different characteristics in device utilization.
- Task can generate requests while running. TBPM considers CPU time of tasks while deciding the power states
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Data structures:
- device-requester utilization matrix U (d, r) : utilization of device d by requester r;
- processor utilization vector P ( r ) : percentage of processor time used by requester.