Load Scheduling

2 Basic techniques for mapping virtual processor partitions to actual processor partitions are as follows.

• Round Robin - Map Virtual Processor i to Real Processor i mod n.
• Processor scheduling -

1.

Estimate cost Ci of joining the tuples of Ri and Si such that
Ciest = Riest + Siest + Ri Join Siest
where
Riest is the number of R tuples mapped to partition i
Siest is the number of S tuples mapped to partition i
and
Ri Join Si est is an estimate of the number of tuples in Ri Join Si .

2.

Sort in decreasing order of estimated cost.

3.

Using the LPT (Lowest Processor Time) Heuristic schedule (map) the virtual processors to the least loaded processor.