CSC/ECE 506 Fall 2007/wiki1 1.3.3 1.3.4 chase2007
Introduction to Parallel Computer Architecture ->Fundamental Design Issues -> Performance (section 1.3.4)
What is Computer Performmace?
Computer performance is a measure of the out put of a computer with with respect to time and resources used.
Performance metrics
Following are the important metrics used to measure a computer's performance:
1.Latency: The time taken to perform an operation 2.Bandwidth:The rate at which the operations are performed 3.Cost: The impact these operations have on the execution time of the program
All the above metrics can be used to define a uniprocessor systems where a single CPU operates.
However, in the context of parallel computers, it becomes difficult to express the performance in above atated metrics. The reason for this is the communication between the processors that occurs mostly in the form of data transfers between the processors. So, to completely define the performace of a parallel computer, the following metrics are also considered.
1.Data Transfer Time:
It is the time taken for initiation of a data transfer and the time required for actual data transfer.So the Data Transfer Time can be given as:
Transfer Time (n) = <math>T_0+\frac{n}{B}</math>
2.Overhead and Occupancy 3.Communication Cost