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Performance Estimates

Complexity analysis = theoretical performance estimation.

It assists us to choose the most appropriate algorithm.

We can also consider an experimental approach to performance:

  • determine the critical (frequent/expensive) operations in the system
  • estimate the likely number of occurrences on classes of data
  • combine the two to produce a cost estimate
E.g. a program reads 100 disk pages and performs 100,000 adds per page.

Cost  =  100(Cost(disk) + 105.Cost(add))  =  102(10-1s +105.10-6s)

Need to know relative costs of various operations.