Currently the CPU subsystem of Collectl can get the CPU loading but no CPU power state. My idea is that tracing turbostat then developing a collectl module to get the CPU power state. It can be used to monitor C-state or frequency.
Reference: Collectl's HelloWorld module, turbostat
On February 12th, 2015, the DMTF released version 3.0.0 of the System Management BIOS Reference Specification. This update isn't just adding enumerated values to existing structures, as previous updates did. It is also introducing a new entry point format which allows for larger tables and structures. Support for this needs to be added to dmidecode.
Additionally, reading the entry point and the table from /dev/mem is no longer possible on all systems, so some work is in progress to offer an alternative interface through sysfs. It would be great to finalize this and release a new version of dmidecode that would support both SMBIOS version 3.0 and this new kernel interface.