System Monitoring with lo2s: Power and Runtime Impact of C-State Transitions

In this paper, we present improvements to the low-overhead performance monitoring tool lo2s. We combine a detailed recording of system events with information from a high-resolution power measurement, to record the scheduling of applications and C-state transitions. These sub-millisecond transitions are difficult to observe with traditional approaches. Our methodology provides us with insights into the behavior of the system before, during, and after C-state transitions of processors cores.