Software Engineering

11.3 
Performance allocation
It is imperative that the software performance requirements be allocated among the 
elements of the functional architecture. This allocation must address the duration 
of each software function, and the accuracy and precision associated with math-
ematical calculations. The software functional performance should only address the 
execution time associated with carrying out software tasks. The performance asso-
ciated with user input and output and interfacing with external systems and other 
software products should be included in the determination of the performance of 
the operational or business process.
Software performance 
is
 dependent on the execution of the computing technol-
ogy and the availability of adequate hardware resources. Performance bottlenecks 
may arise when access to shared resources becomes contentious and delay func-
tional execution or extend the time for a function to be performed.
A bottleneck is a phenomenon where the performance or capacity of an entire 
system is limited by a single or limited number of components or resources. 
The term bottleneck is taken from the “assets are water” metaphor. As water is 
poured out of a bottle, the rate of outflow is limited by the width of the con-
duit of exit—that is, bottleneck. By increasing the width of the bottleneck one can 
increase the rate at which the water flows out of the neck at different frequencies. 
Such limiting components of a system are sometimes referred to as bottleneck 
points.
2
Therefore, software performance requirements must be allocated among the ele-
ments of the functional architecture. This involves addressing software execution 
or timing, as well as resource utilization to avoid resource-imposed performance 
degradation.
2 
See 
http://en.wikipedia.org/wiki/Bottleneck

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