CPU Utilization while Scaling Resources in the Cloud

Abstract—CPU utilization in a virtual machine instance directly impacts the overall cost for the cloud service provider since it generates costs for power consumption and cooling. We are interested to determine the total CPU utilization behavior while scaling the number of CPU cores using the same server load. The experiments are based on two simple web services to utilize the virtual machine instance varying the number of concurrent messages and their size. The goal is to check if the total CPU utilization while scaling will be sublinear (smaller than the number of cores), and if it is greater than the CPU utilization when executed without scaling (using only one CPU core) due to task scheduling, coherence, etc. The experiments prove only that the total CPU utilization will be sublinear. We observe a region (workload with smaller number of concurrent messages) where the total CPU utilization decreases while scaling, compared to the case without scaling. We also determine the correlation between the CPU utilization with message size and the number of concurrent messages