Utilization is virtually useless as a metric
Adrian N. Cockcroft · Int. CMG Conference · 2006
We have all been conditioned over the years to use utilization or %busy as the primary metric for capacity planning. Unfortunately, with increasing use of CPU virtualization and sophisticated CPU optimization techniques such as hyper-threading and power management the measurements we get from the systems are “virtually useless”. This paper will explain many of the ways in which the data we depend upon is distorted, and proposes that we turn to direct measurement of the fundamental alternatives, and express capacity in terms of headroom, in units of throughput within a response time limit.