Idle CPU power management: cpuidle

CNXSoft: This is a guest post by Daniel Thompson, Principal Software Engineer at RISCstar Solutions, about Linux CPU power management for embedded systems, specifically covering cpuidle in depth. Twenty years ago, it was easy for an operating system kernel to go idle: when there were no tasks to run, “the idle loop” would be scheduled. Early idle loops were basically empty infinite loops that did nothing while waiting for the next interrupt to happen. This saved power simply by avoiding running instructions that needed power-hungry components such as the cache or FPU! Over time, changing technology has allowed multiple additional hardware mechanisms to reduce power to be introduced. With these new options available today, the idle loop is responsible for choosing and deploying the “best” way to go idle. As a brief reminder, entering and returning from an idle state has a cost, and that cost can be measured both [...] The post Idle CPU power management: cpuidle appeared first on CNX Software - Embedded Systems News.