usl (version 3.0.3)

limit.scalability,USL-method: Scalability limit of a USL model

Description

Calculate the scalability limit for a specific model.

Usage

# S4 method for USL
limit.scalability(object, alpha, beta, gamma)

Value

A numeric value for the system capacity limit (e.g. throughput).

Arguments

object

A USL object.

alpha

Optional parameter to be used for evaluation instead of the parameter computed for the model.

beta

Optional parameter to be used for evaluation instead of the parameter computed for the model.

gamma

Optional parameter to be used for evaluation instead of the parameter computed for the model.

Details

The scalability limit is defined as:

$$Xroof = \frac{\gamma}{\alpha}$$

This is the upper bound (Amdahl asymptote) of system capacity.

The parameters alpha, beta and gamma are useful to do a what-if analysis. Setting these parameters override the model parameters and show how the system would behave with a different contention or coherency delay parameter.

The scalability limit is undefined if alpha is zero.

This function accepts an argument for beta although the value is not required to perform the calculation. This is on purpose to provide a coherent interface.

See Also

usl, peak.scalability,USL-method optimal.scalability,USL-method

Examples

require(usl)

data(specsdm91)

limit.scalability(usl(throughput ~ load, specsdm91))
## The throughput limit is about 3245