Cpuidle from user space

In this paper we present a user space cpuidle governor. In addition to providing a user space interface to pick idle states for individual cores in a multicore system, the governor also ensures that each core stays in the specified idle state forever. In other words, the cores do not wake up from a specified idle state unless specified by the user. This gives a user complete control over a core’s idle states without worrying about any kind of wake-ups. A user space governor can be very useful in scenarios where every workload is run with a customized cpuidle power saving algorithm. Coding different algorithms and dynamically switching between them is fairly simpler in user space when compared to kernel space. From our evaluation results, we have concluded that this technique does not hurt power consumption savings or performance benefits in any way.