Hardware Performance Counter (HWPC) Sensor is a tool that monitors the Intel CPU performance counter and the power consumption of the CPU. It uses the RAPL (Running Average Power Limit) technology to monitor CPU power consumption, which is only available on Intel Sandy Bridge architecture or higher. The sensor uses the perf API of the Linux kernel and needs root access to be used. It cannot be used in a virtual machine and must access the real CPU register to read performance counter values.