Power Management and Performance in Enteprise Linux (EL7)
...that service conflicts with cpupower. As far as I can tell cpupower gets completely ignored by systemd once tuned is enabled. So you can either disable tuned and use cuppower or forget about cpupower and stick with tuned.
Full documentation on the 'tuned' utility can be found in the Fedora Power Management Guide. The 'tuned' utility takes advantage of udev's dynamic device management capabilities to statically assign power/performance values through sysctl and sysfs settings to a various devices; including CPU, networking devices, disks, USB, audio, video, vm.
While the utility supports dynamic tuning as well, we won't concern ourselves with that feature here as it is disabled by default in EL7. Furthermore, according to the project's web page, dynamic tuning is experimental and limited in scope.
There are various profiles optimized for powersave, performance and virtual hosts/guests. You can view all available profiles with the following command:
# tuned-adm listThe profiles are held in the /usr/lib/tuned/ directory. The default profile is 'balanced'; if you want to switch to the e.g. powersave profile use:
# tuned-adm profile powersaveThis setting is persistent across reboots. One can also create custom profiles that can either include and/or override settings from system profiles. Your custom profiles can be put into the /etc/tuned/ directory, and they have higher priority in case of conflict.
A caveat worth mentioning, as explained in Fedora's Power Management Docs:
The powersave profile may not always be the most efficient. Consider there is a defined amount of work that needs to be done, for example a video file that needs to be transcoded. Your machine can consume less energy if the transcoding is done on the full power, because the task will be finished quickly, the machine will start to idle and can automatically step-down to very efficient power save modes. On the other hand if you transcode the file with a throttled machine, the machine will consume less power during the transcoding, but the process will take longer and the overall consumed energy can be higher. That is why the balanced profile can be generally a better option.