Applications built into a phone might have default settings controlling their power consumption based on how people are likely to use them, but it would be hard to set those parameters for newly downloaded software, Levis said. Those applications could be assigned to run in a highly constrained mode at first, which would ensure that unfamiliar software couldn't quickly drain the battery. Then, if users found the new application ran too slowly, they could push a "more power" button to boost the power allocated to it, he said.

Cinder uses a variety of mechanisms to achieve this level of power control. The main piece is what Levis called the "power lock," a simple mechanism to control all kinds of workloads. It takes the place of what may be dozens of different policies in a typical system today, he said. The OS also uses asynchronous I/O, a feature used in high-performance servers today. Asynchronous I/O cuts down on delays from communication between applications and the operating system and lets the OS schedule workloads. Whereas asynchronous I/O is used in servers for performance reasons, Cinder would use it to minimize power consumption, Levis said.