Reference Formulae

Knowledge Base & Community Wiki

Reference Formulae

in

Here’s a list of some of the most commonly used Fundamental Formulae from a Performance modelling standpoint.

 

  • X = C / T ………[ X = Throughput, C = Number of Completions, T = Total Elapsed Time]

 

  • Di = Vi * Si ……… [D = Service Demand, V = Visit Count, S = Service Time]

 

  • Uavg = X * Savg ……… [ Uavg = Utilization, X = Throughput, Savg = Service Time]

 

  • Xmax < or = 1 / Smax ……… [ Xmax = Max Throughput, Smax = Max Service Time]

 

  • Savg = B / C ……… [ Savg = Service Time, C = Completions]

 

  • Ravg = Qt + Savg ……… [ R = Response Time, Q = Queuing Time, Savg = Service Time]

 

  • Qavg = X * Qt ……… [ Q = Queue Length, Qt = Queuing Time, X = Throughput]

 

  • N = (R+Z) * X : Little’s Law ……… [ N = Number in System, R = Response Time, X = Throughput, Z = Think Time]

 

Little’s Law provides a set of equations to understand the relationship between User Concurrency in a System, the Response time (Response = Wait time or Queue Time + Service Time) and the Transactional throughput.

Little’s Law was given to us by Prof. John Little (http://en.wikipedia.org/wiki/Little%27s_law).

Modelling Solution: VisualizeIT offers access to a bunch of Analytical Models, Statistical Models and Simcropped-visualize_it_logo__transparent_090415.pngulation Models. Access to all the Analytical (Mathematical) models is free. We recommend you try out the Analytical models at VisualizeIT which are free to use and drop us a note with your suggestions, input and comments. You can access the VisualizeIT website here and the VisualizeIT modelling solution here –VisualizeIT.

 

This entry was posted in   .
Bookmark the   permalink.

Admin has written 0 articles

VisualizeIT Administrator & Community Moderator