Analytical Performance Modeling

<h2 id="the-model">The Model</h2>
<p>The model is fed with measurements of transaction resource demands (<a href="/facts/CPU/Jxp1bqMV">CPU</a>, disk I/O, <a href="/facts/LAN/edUDxJ6J">LAN</a>, <a href="/facts/Wide_area_network/mAkW4gr3">WAN</a>), weighted by the transaction-mix (business transactions per unit of time). The weighted transaction resource demands are added-up to obtain the resource demands and divided by the resource capacity to obtain the resource loads. Changes in response time can also be predicted by the model. For example, in a simple case with a single resource, the response time formula: R=S/(1-U) where R=response_time, S=service_time, U=utilization, will calculate the response time as the utilization of that resource varies between 0=0% busy to 1=100% busy.<a class="footnote-ref" id="fnref:2" href="#fn:2"><sup>2</sup></a> This formula is a good approximation of the more complex math of <a href="/facts/Queueing_theory/8NDl56EM">queueing theory</a> and requires adjustment when dealing with multiple resources.
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<h2 id="see-also">See also</h2>
<ul><li><a href="/facts/Roofline_model/FpbA3SWV">Roofline model</a></li></ul>

<h2 id="references">References</h2>

<ol>
<li id="fn:1"><p>Wescott, Bob (2013). The Every Computer Performance Book, Chapter 7: Modeling. CreateSpace. ISBN 978-1482657753. <a href="978-1482657753" target="_blank">978-1482657753</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li>
<li id="fn:2"><p>Wescott, Bob (2013). The Every Computer Performance Book, Chapter 3: Useful laws. CreateSpace. ISBN 978-1482657753. <a href="978-1482657753" target="_blank">978-1482657753</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li>
</ol>

Analytical Performance Modeling open-in-new

Analytical Performance Modeling