Cloud management tasks such as performance diagnosis, workload placement, and power management depend critically on estimating the utilization of an application. But, it is challenging to measure actual utilization for polled IO network functions (NFs) without code instrumentation. We ask if CPU events (e.g., data cache misses) measured using hardware performance counters are good at estimating utilization for polled-IO NFs. We find a strong correlation between several CPU events and NF utilization for three representative types of network functions. Inspired by this finding, we explore the possibility of computing a universal estimation function that maps selected CPU events to NF utilization estimates for a wide-range of NFs, traffic profiles and traffic loads. Our NF-specific estimators and universal estimators achieve absolute estimation errors below 6% and 10% respectively.
